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|Trouble Code: P0401 (4.2L V6 VIN 2 Auto) |Print this code data[pic] |
|Insufficient EGR Flow Detected | |
Number of Trips to Set Code: 2
OBD II Monitor Type: CCM Details
Indicators: MIL Details
Trouble Code Conditions:
Engine started, engine running in closed loop under steady cruise conditions, and the PCM detected the DPFE sensor input indicated insufficient EGR gas flow. Run the KOER Self-Test, and if DTC P1408 is present, the fault is currently present.
Possible Causes:
• DPFE sensor signal circuit is shorted to ground
• DPFE sensor VREF circuit is open between sensor and PCM
• DPFE sensor downstream hose off or plugged
• DPFE sensor hoses both off, loose or damaged
• DPFE sensor hoses connected wrong (reversed)
• EGR orifice tube is damaged or restricted
HE70 DTC P0401: RUN KOER SELF-TEST
DIAGNOSTIC TROUBLE CODE (DTC) P0401 INDICATES THAT CONTINUOUS MEMORY SELF-TEST HAS DETECTED INSUFFICIENT EGR FLOW.POSSIBLE CAUSES:
• Fault in vacuum supply to EGR vacuum regulator solenoid.
• EGR valve stuck closed or iced.
• EGR valve diaphragm leaks.
• EGR valve or flow path restricted.
• EGR vacuum hose off, plugged or leaks.
• VPWR circuit open to EGR Vacuum Regulator solenoid.
• EVR circuit to PCM open.
• EVR circuit to PCM shorted to PWR.
• Differential Pressure Feedback EGR (D.P.F. EGR) sensor pressure hoses both connected improperly.
• D.P.F. EGR sensor pressure hoses reversed.
• D.P.F. EGR sensor VREF circuit open.
• Downstream pressure hose off.
• Downstream pressure hose plugged.
• Damaged orifice tube assembly.
• Damaged EGR Vacuum Regulator solenoid.
• Damaged D.P.F. EGR sensor.
• Damaged PCM.
• Run KOER Self-Test.
Is KOER DTC P1408 output?
|Yes |No |
|The KOER Self-Test has detected an EGR fault |REMOVE and INSPECT the EGR Valve and intake manifold EGR port for restriction. If|
|that is currently present. GO to HE71. |OK, the fault that produced DTC P0401 is intermittent. GO to HE90 |
HE71 DTC P1408: RETRIEVE CONTINUOUS MEMORY DTCS
DIAGNOSTIC TROUBLE CODE (DTC) P1408 INDICATES THAT KEY ON ENGINE RUNNING (KOER) SELF-TEST HAS DETECTED EGR FLOW OUT OF RANGE.POSSIBLE CAUSES:
• Fault in vacuum supply to EGR Vacuum Regulator solenoid.
• EGR valve stuck closed or iced.
• EGR valve diaphragm leaks.
• EGR valve or flow path restricted.
• EGR vacuum hose off, plugged or leaks.
• VPWR circuit open to EGR vacuum regulator solenoid.
• EVR circuit to PCM open.
• EVR circuit to PCM shorted to PWR.
• Differential Pressure Feedback EGR (D.P.F. EGR) sensor pressure hoses both improperly connected.
• D.P.F. EGR sensor pressure hoses reversed.
• D.P.F. EGR sensor VREF circuit open.
• Improper downstream pressure hose connection.
• Downstream pressure hose plugged.
• Damaged orifice tube assembly.
• Damaged EGR Vacuum Regulator solenoid.
• Damaged D.P.F. EGR sensor.
• Damaged PCM.
Note: If any DTC other than DTC P1406 is output, record DTC and refer to Diagnostic Trouble Code Charts in Section 4A after completing this Pinpoint Test.
• Retrieve all Continuous Memory DTCs.
Is DTC P1406 output?
|Yes |No |
|GO to HE60. |GO to HE72. |
HE72 RUN KOER SELF-TEST WHILE MONITORING EGR VACUUM
• KEY OFF.
• Disconnect vacuum hose at EGR valve and connect hose to a vacuum gauge.
Note: Since the EGR vacuum hose is disconnected, ignore DTCs during this KOER Self-Test.
• Run Key On Engine Running (KOER) Self-Test while monitoring gauge. Approximately 30 seconds into test, EGR flow will be requested for a few seconds. The vacuum at this time should increase above 5.4 kPa (1.6 in-Hg) to open the valve.
Does the vacuum increase to 10 kPa (3.0 in-Hg) or greater at any time during KOER Self-Test?
|Yes |No |
|The vacuum indicated is sufficient to open the EGR valve. Fault is unlikely |The vacuum indicated is insufficient to open the |
|to be in EGR vacuum control system. GO to HE73. |EGR valve. GO to HE80. |
HE73 INSPECT D.P.F. EGR SENSOR PRESSURE HOSES
• KEY OFF.
• Visually inspect both pressure hoses for reversed connection at D.P.F. EGR sensor or at orifice tube assembly.
• Inspect both hoses for improper routing. Hoses should not be pinched or have dips where water could settle or freeze.
• Inspect both hoses for leaks and blockage.
• Inspect D.P.F. EGR sensor and orifice tube assembly for blockage or damage at the pick up tubes.
Is there a fault detected?
|[pic] |
| |
|Yes |No |
|SERVICE pressure hoses as necessary. RECONNECT all components. COMPLETE PCM Reset to clear DTCs. RERUN Quick |GO to HE74. |
|Test. | |
HE74 CHECK D.P.F. EGR SENSOR OUTPUT BY APPLYING VACUUM WITH HAND PUMP
• KEY OFF.
• Disconnect pressure hoses at D.P.F. EGR sensor.
• Connect a hand vacuum pump to the downstream connection at sensor (intake manifold side of sensor or the smaller diameter pickup tube.)
• Key on, engine off.
• Access DPFEGR PID with a Scan Tool and note PID value.
• Apply 27-30 kPa (8-9 in-Hg) vacuum to the D.P.F. EGR sensor and hold for a few seconds.
• Quickly release vacuum.
• The DPFEGR PID voltage must be between 0.2 and 1.3 volt with the key on and no vacuum applied.
• The DPFEGR PID voltage must increase to greater than 4.0 volts with the vacuum applied.
• The DPFEGR PID must drop to less than 1.5 volts in less than 3 seconds when vacuum is released.
Does the DPFEGR PID voltage indicate a fault in the D.P.F. EGR sensor?
|Yes |No |
|GO to HE75. |RECONNECT pressure hoses. GO to HE76. |
HE75 MEASURE VREF VOLTAGE AT D.P.F. EGR SENSOR VEHICLE HARNESS CONNECTOR
• DISCONNECT D.P.F. EGR SENSOR.
• Key on, engine off.
• Measure voltage between the sensor VREF circuit and SIG RTN circuit at the D.P.F. EGR sensor vehicle harness connector.
Is VREF voltage between 4.0 and 6.0 volts?
|Yes |No |
|REPLACE damaged D.P.F. EGR sensor. RECONNECT all components. COMPLETE PCM Reset to clear|VREF voltage is out of range. GO to |
|DTCs. RERUN Quick Test. |Pinpoint Test Step C1. |
HE76 CHECK EGR VALVE FUNCTION BY APPLYING VACUUM WITH HAND PUMP
• KEY OFF.
• Disconnect vacuum hose at EGR valve and plug hose.
• Connect a hand vacuum pump to EGR valve.
• Start engine and bring to idle.
• Access DPFEGR and RPM PIDs with a Scan Tool.
• Slowly apply 27-34 kPa (8-10 in-Hg) of vacuum to the EGR valve and hold it for 10 seconds. If engine wants to stall, increase rpm with throttle to maintain a minimum of 1000 rpm.
• Look for the following:
• EGR valve starts opening at about 5.4 kPa (1.6 in-Hg) vacuum indicated by increasing DPFEGR PID voltage.
• DPFEGR PID voltage increasing until EGR valve is fully open. DPFEGR PID must read 2.5 volts minimum with full vacuum applied.
• DPFEGR PID voltage steady when vacuum is held. If voltage drops within a few seconds, the EGR valve or vacuum source can be leaking.
Does the DPFEGR PID voltage indicate that the EGR valve is operating as described in this test?
|Yes |No |
|RECONNECT all components. GO |REMOVE and INSPECT the EGR valve for signs of contamination, unusual wear, carbon deposits, |
|to HE85. |binding, leaking diaphragm and other damage. If EGR valve is OK, look for an obstructed EGR port in|
| |the intake manifold or plugged orifice tube assembly. SERVICE as necessary (use Rotunda EGR Valve |
| |Cleaner 021-00056 or equivalent, if needed). RECONNECT all components. COMPLETE PCM Reset to clear |
| |DTCs. RERUN Quick Test. |
HE80 CHECK VACUUM SOURCE AND VACUUM HOSES TO AND FROM EGR VACUUM REGULATOR SOLENOID
• KEY OFF.
• Disconnect vacuum hoses at EGR Vacuum Regulator solenoid.
• Connect EGR Vacuum Regulator solenoid vacuum source hose to a vacuum gauge.
• With engine warm and at idle, take vacuum gauge reading.
• Inspect vacuum lines between vacuum source and EGR Vacuum Regulator solenoid and between EGR Vacuum Regulator solenoid and EGR valve for leaks, kinks, disconnects, blockage, routing or any damage.
Is the vacuum gauge reading a minimum of 51 kPa (15 in-Hg) at idle and vacuum lines OK?
|Yes |No |
|RECONNECT all components. GO to HE81. |ISOLATE fault and SERVICE as necessary. RECONNECT all components. COMPLETE PCM Reset to |
| |clear DTCs. RERUN Quick Test. |
HE81 CHECK VPWR TO EGR VACUUM REGULATOR SOLENOID
• KEY OFF.
• EGR Vacuum Regulator solenoid disconnected.
• Key on, engine off.
• Measure voltage between VPWR circuit and chassis ground at the EGR Vacuum Regulator solenoid vehicle harness connector.
Is EGR Vacuum Regulator solenoid VPWR voltage greater than 10.5 volts?
|Yes |No |
|GO to HE82. |SERVICE open in EGR Vacuum Regulator solenoid VPWR circuit. RECONNECT all components. COMPLETE PCM Reset to clear |
| |DTCs. RERUN Quick Test. |
HE82 MEASURE RESISTANCE ACROSS EGR VACUUM REGULATOR SOLENOID
• KEY OFF.
• EGR Vacuum Regulator solenoid disconnected.
• Measure resistance across EGR Vacuum Regulator solenoid.
Is solenoid resistance between 26 and 40 ohms?
|Yes |No |
|GO to HE83. |REPLACE damaged EGR Vacuum Regulator solenoid. RECONNECT all components. COMPLETE PCM Reset to clear DTCs. RERUN |
| |Quick Test. |
HE83 CHECK EVR CIRCUIT FOR SHORT TO PWR
• KEY OFF.
• EGR Vacuum Regulator solenoid disconnected.
• Disconnect PCM. Inspect for damaged or pushed out pins, corrosion, loose wires. Service as necessary.
• Install breakout box, leave PCM disconnected.
• Key on, engine off.
• Measure voltage between Test Pin 47 (EVR) and chassis ground.
Is voltage greater than 1.0 volt?
|Yes |No |
|SERVICE EVR circuit for short to PWR. RECONNECT all components. COMPLETE PCM Reset to clear DTCs. RERUN Quick |GO to HE84. |
|Test. | |
HE84 CHECK EVR CIRCUIT FOR OPEN IN HARNESS
• KEY OFF.
• EGR Vacuum Regulator solenoid disconnected.
• Breakout box installed, PCM disconnected.
• Measure resistance between Test Pin 47 (EVR) and EVR circuit at the EGR Vacuum Regulator solenoid vehicle harness connector.
Is resistance less than 5.0 ohms?
|Yes |No |
|RECONNECT EGR Vacuum Regulator solenoid. GO to |SERVICE open in EVR circuit. RECONNECT all components. COMPLETE PCM Reset to |
|HE85. |clear DTCs. RERUN Quick Test. |
HE85 CHECK EGR VACUUM REGULATOR SOLENOID VACUUM OUTPUT CAPABILITY BY GROUNDING EVR CIRCUIT
• KEY OFF.
• Breakout box installed, PCM connected.
• EGR Vacuum Regulator solenoid connected.
• Disconnect vacuum hose at the EGR valve and connect to a vacuum gauge.
• Key on, engine running.
• With engine at idle, jumper Test Pin 47 (EVR) to chassis ground.
Is vacuum gauge reading 13.5 kPa (4.0 in-Hg) or greater?
|Yes |No |
|REPLACE damaged PCM. RECONNECT all components. |REPLACE damaged EGR Vacuum Regulator solenoid. RECONNECT all components. |
|RERUN Quick Test. |COMPLETE PCM Reset to clear DTCs. RERUN Quick Test. |
HE90 INSPECT EGR SYSTEM FOR AN INTERMITTENT FAILURE
• KEY OFF.
• Visually inspect the EGR system for signs of intermittent failure.
Is a fault found?
|Yes |No |
|SERVICE fault as necessary. RECONNECT all components. COMPLETE PCM Reset to clear DTCs. RERUN Quick Test. |GO to HE91. |
HE91 CHECK EGR VALVE FUNCTION BY APPLYING VACUUM WITH HAND PUMP
• KEY OFF.
• Disconnect vacuum hose at EGR valve and plug hose.
• Connect a hand vacuum pump to EGR valve.
• Start engine and bring to idle.
• Access DPFEGR and RPM PIDs with a Scan Tool.
• Slowly apply 17-34 kPa (5-10 in-Hg) of vacuum to the EGR valve and hold it for 10 seconds. If engine wants to stall, increase rpm with throttle to maintain a minimum of 800 rpm.
• Look for the following:
• EGR valve starts opening at about 5.4 kPa (1.6 in-Hg) vacuum indicated by increasing DPFEGR PID voltage.
• DPFEGR PID voltage increasing until EGR valve is fully open. DPFEGR PID should read 2.5 volts minimum with full vacuum applied.
• DPFEGR PID voltage steady when vacuum is held. If voltage drops within a few seconds, the EGR valve or vacuum source could be leaking.
Does the DPFEGR PID voltage indicate that the EGR valve is operating as described in this test?
|Yes |No |
|GO to HE92. |REMOVE and INSPECT the EGR valve for signs of contamination, unusual wear, carbon deposits, binding, leaking |
| |diaphragm and other damage. If EGR valve is OK, look for an obstructed EGR port in the intake manifold. SERVICE as |
| |necessary (use Rotunda EGR Valve Cleaner 021-00056 or equivalent, if needed). RECONNECT all components. COMPLETE PCM|
| |Reset to clear DTCs. RERUN Quick Test. |
HE92 INSPECT EGR VACUUM SIGNAL SUPPLY FOR INTERMITTENT FAILURE
• KEY OFF.
• Disconnect PCM. Inspect for damaged or pushed out pins, corrosion and loose wires. Service as necessary.
• Install breakout box and connect PCM to breakout box.
• Disconnect hose at EGR valve and connect to a vacuum gauge.
• Key on, engine running.
• Jumper Test Pin 47 (EVR) to chassis ground to activate the EVR to full ON. At idle, the vacuum gauge should read above 13.5 kPa (4.0 in-Hg).
• Observe vacuum gauge for an indication of a fault while performing the following:
• Lightly tap on the EGR Vacuum Regulator solenoid and wiggle the EGR Vacuum Regulator solenoid connector, vacuum lines and vehicle harness between the solenoid and PCM. A fault is indicated by a sudden drop in vacuum reading.
Is a fault indicated?
|Yes |No |
|ISOLATE fault and SERVICE as necessary. RECONNECT|Unable to duplicate or identify fault at this time. (In cold climates, the EGR |
|all components. COMPLETE PCM Reset to clear DTCs.|valve may temporarily freeze shut and thaw when the engine warms up causing the|
|RERUN Quick Test. |intermittent DTC.) GO to Pinpoint Test Step Z1 with the following data: DPFEGR |
| |and EGRVR PIDs and list of Possible causes. |
HE100 EGR DIAGNOSIS BY SYMPTOM: CHECK FOR EGR FLOW WITH EGR VACUUM HOSE DISCONNECTED AND PLUGGED
NOTE: PERFORM KOER SELF-TEST AND SERVICE ANY DTCS BEFORE PROCEEDING WITH THIS TEST.THE SYMPTOM CHARTS HAVE INDICATED POSSIBLE EGR FLOW AT IDLE WITH NO EGR DIAGNOSTIC TROUBLE CODES OUTPUT.POSSIBLE CAUSES:
• EGR valve not fully seating.
• EGR vacuum regulator solenoid vent restricted.
• Damaged EGR Vacuum Regulator solenoid.
• Disconnect vacuum hose at EGR valve and plug hose.
• Key on, engine off.
• Access DPFEGR PID with a Scan Tool and note voltage.
• Typical D.P.F. EGR sensor voltage with no EGR flow is between 0.2 and 1.3 volt.
• Start engine and bring to idle.
• With engine at idle, look at the DPFEGR PID voltage and compare to the engine off reading. An increase in the voltage at idle indicates that the differential pressure feedback EGR sensor is sensing EGR flow.
Is the DPFEGR PID voltage greater at idle by a minimum of 0.15 volt than with the engine off?
|Yes |No |
|The DPFEGR PID voltage is indicating EGR flow at idle. Since the EGR |This indicates a fault in the EGR valve vacuum supply. |
|vacuum hose is disconnected and plugged, the fault is most likely in the|INSPECT the EGR Vacuum Regulator solenoid vent and vent |
|EGR valve. REMOVE and INSPECT the EGR valve for signs of contamination, |filter for restrictions. SERVICE as necessary. If OK, |
|unusual wear, carbon deposits, binding and other damage. SERVICE as |REPLACE EGR Vacuum Regulator solenoid. VERIFY a symptom |
|necessary (use Rotunda EGR Valve Cleaner 021-00056 or equivalent, if |no longer exists. |
|needed). RECONNECT all components. VERIFY a symptom no longer exists. | |
HE110 DTC P1409: MEASURE RESISTANCE ACROSS EGR VACUUM REGULATOR SOLENOID
DIAGNOSTIC TROUBLE CODE (DTC) P1409 INDICATES THAT SELF-TEST HAS DETECTED AN ELECTRICAL FAULT IN THE EVR CIRCUIT.POSSIBLE CAUSES:
• Open EVR circuit.
• Open VPWR circuit to EGR Vacuum Regulator solenoid.
• EVR circuit shorted to VPWR.
• EVR circuit shorted to GND.
• Damaged EGR Vacuum Regulator solenoid.
• Damaged PCM.
• Key off.
• Disconnect EGR Vacuum Regulator solenoid.
• Measure EGR Vacuum Regulator solenoid resistance.
Is solenoid resistance between 26 and 40 ohms?
|Yes |No |
|The EGR Vacuum Regulator solenoid resistance is |REPLACE EGR Vacuum Regulator solenoid. RECONNECT all components. COMPLETE PCM|
|within specification. GO to HE111. |Reset to clear DTCs. RERUN Quick Test. |
HE111 CHECK VPWR CIRCUIT VOLTAGE AT EGR VACUUM REGULATOR SOLENOID
• KEY ON, ENGINE OFF.
• EGR Vacuum Regulator solenoid disconnected.
• Measure voltage between VPWR circuit at the EGR Vacuum Regulator solenoid vehicle harness connector and chassis GND.
Is voltage greater than 10.5 volts?
|Yes |No |
|GO to HE112. |SERVICE open in VPWR circuit to EGR Vacuum Regulator solenoid. RECONNECT all components. COMPLETE PCM Reset to |
| |clear DTCs. RERUN Quick Test. |
HE112 CHECK EVR CIRCUIT RESISTANCE
• KEY OFF.
• EGR Vacuum Regulator solenoid disconnected.
• Disconnect PCM. Inspect for damaged or pushed out pins, corrosion, loose wires. Service as necessary.
• Install breakout box and leave PCM disconnected.
• Measure resistance between Test Pin 47 (EVR) and EVR circuit at the EGR Vacuum Regulator solenoid vehicle harness connector.
Is resistance less than 5.0 ohms?
|Yes |No |
|GO to HE113. |SERVICE open in EVR circuit. RECONNECT all components. RERUN Quick Test. |
HE113 CHECK EVR CIRCUIT FOR SHORTS TO POWER OR GROUND
• KEY OFF.
• EGR Vacuum Regulator solenoid disconnected.
• Breakout box installed, leave PCM disconnected.
• Measure resistance between Test Pin 47 (EVR) and Test Pins 71 and 97 (VPWR) at the breakout box.
• Measure resistance between Test Pin 47 (EVR) and Test Pins 24 and 103 (PWR GND) at the breakout box.
Is each resistance greater than 10,000 ohms?
|Yes |No |
|REPLACE damaged PCM. RECONNECT all components. RERUN |SERVICE EVR circuit for short to VPWR or PWR GND. RECONNECT all |
|Quick Test. |components. RERUN Quick Test. |
HE120 CONTINUOUS MEMORY DTC P1409: WIGGLE EGR VACUUM REGULATOR SOLENOID WHILE MONITORING VPWR
CONTINUOUS MEMORY DTC P1409 INDICATES THAT CONTINUOUS MEMORY SELF-TEST HAS DETECTED AN ELECTRICAL MALFUNCTION IN THE EGR VACUUM REGULATOR SOLENOID SOMETIME DURING VEHICLE OPERATION.NOTE: IF DTC P1409 WAS OUTPUT IN KEY ON ENGINE OFF (KOEO) OR KEY ON ENGINE RUNNING (KOER) SELF-TEST, GO TO HE110 TO DIAGNOSE PRESENT FAULT.POSSIBLE CAUSES:
• Open EVR circuit.
• Open VPWR circuit to EGR Vacuum Regulator solenoid.
• EVR circuit shorted to VPWR.
• EVR circuit shorted to GND.
• Damaged EGR Vacuum Regulator solenoid.
• Damaged PCM.
• Disconnect PCM. Inspect for damaged or pushed out pins, corrosion, loose wires.
• Install breakout box, leave PCM disconnected.
• Measure voltage between Test Pin 47 (EVR) and Test Pins 24 (PWR GND) at the breakout box.
• Key on.
• Voltage must read greater than 10.5 volts. For an indication of a fault, look for this voltage to drop while performing the following:
• Lightly tap on the EGR Vacuum Regulator solenoid.
• Wiggle the EGR Vacuum Regulator solenoid connector.
• Grasp the EGR Vacuum Regulator solenoid vehicle harness connector and wiggle wires between solenoid and PCM.
Is a fault indicated?
|Yes |No |
|ISOLATE fault and SERVICE as necessary. RECONNECT all |Unable to duplicate or identify fault at this time. GO to Pinpoint Test |
|components. RERUN Quick Test. |Step Z1 with the following data: DPFEGR and EGRVR PIDs and list of |
| |possible causes. |
HJ30 DTC P0401: CHECK VACUUM SUPPLY TO EGR VACUUM REGULATOR SOLENOID
DIAGNOSTIC TROUBLE CODE (DTC) P0401 INDICATES THAT SELF-TEST HAS DETECTED INSUFFICIENT EGR FLOW.POSSIBLE CAUSES:
• Disconnected or damaged vacuum hoses.
• Damaged EGR valve.
• Damaged EGR Valve Position sensor.
• Damaged EGR Vacuum Regulator solenoid.
• Key off.
• Disconnect vacuum supply hose to EGR Vacuum Regulator solenoid at the solenoid.
• Connect the vacuum supply hose to a vacuum gauge.
• Start engine and check the vacuum at idle.
Is the supply vacuum greater than 34 kPa (10 in-Hg)?
|Yes |No |
|REMOVE vacuum gauge and RECONNECT hose. GO |SERVICE vacuum supply to EGR Vacuum Regulator solenoid. INSPECT vacuum hoses, |
|to HJ31. |connections, and vacuum reservoirs leading to intake manifold as necessary. |
HJ31 CHECK VACUUM HOSE TO EGR VALVE
• KEY OFF.
• Carefully check vacuum hose between EGR valve and EGR Vacuum Regulator solenoid for obstructions, cracks, loose connection, blockage, kinks, leaks, icing.
Is vacuum hose OK?
|Yes |No |
|GO to HJ32. |SERVICE or REPLACE vacuum hose as necessary. RECONNECT all components. COMPLETE PCM Reset to clear DTCs. RERUN |
| |Quick Test. |
HJ32 CHECK EGR VALVE FUNCTION
• KEY OFF.
• Remove and plug the vacuum hose connected to EGR valve.
• Disconnect the Idle Air Control (IAC) valve assembly.
• Key on, engine running.
• Access RPM PID with a Scan Tool or install a tachometer, Rotunda 059-00010 or equivalent.
• With engine at idle, slowly apply 17-34 kPa (5-10 in-Hg) vacuum to the EGR valve with a hand vacuum pump while observing rpm.
Does the idle speed drop more than 100 rpm with full vacuum applied and return to normal (+/- 25 rpm) after the vacuum is removed?
|Yes |No |
|RECONNECT IAC valve assembly. GO to |SERVICE or REPLACE DAMAGED EGR valve. RECONNECT all components. COMPLETE PCM Reset to |
|HJ33. |clear DTCs. RERUN Quick Test. |
HJ33 CHECK EGRVP PID WHILE EXERCISING EGR VALVE
• KEY ON, ENGINE OFF.
• Access EGRVP PID with a Scan Tool.
• Slowly apply 17-34 kPa (5-10 in-Hg) vacuum to the EGR valve with a hand vacuum pump while observing PID voltage.
Note: The EGR Valve Position sensor voltage with the EGR valve closed is between 0.24 and 0.67 volts.
Does the PID voltage indicate 3.0 volts or greater with full vacuum applied?
|Yes |No |
|GO to HJ34. |REPLACE damaged EGR Valve Position sensor. RECONNECT all components. COMPLETE PCM Reset to clear DTCs. RERUN Quick|
| |Test. |
HJ34 CHECK EGR VACUUM REGULATOR SOLENOID FUNCTION
• KEY OFF.
• Connect the EGR valve vacuum hose to a vacuum gauge.
• Disconnect PCM. Inspect for damaged or pushed out pins, corrosion and loose wires. Service as necessary.
• Install breakout box, reconnect PCM.
• Key on, engine running.
• Jumper Test Pin 47 (EVR) to Test Pin 51 or 103 (PWR GND) at the breakout box.
Does the vacuum gauge indicate a vacuum of 17 kPa (5.0 in-Hg) minimum at the EGR valve?
|Yes |No |
|GO to HJ35. |REPLACE damaged EGR Vacuum Regulator solenoid. RECONNECT all components. RERUN Quick Test. |
HJ35 CHECK FOR INTERMITTENT EGR VACUUM REGULATOR SOLENOID AND CIRCUIT
• KEY ON, ENGINE RUNNING.
• Jumper connected from Step HJ34.
• Vacuum should read greater than 17 kPa (5.0 in-Hg).
• Observe the EGR valve vacuum to drop as an indication of a fault while performing the following:
• Lightly tap on EGR Vacuum Regulator solenoid.
• Wiggle the solenoid connector and vacuum lines.
• Grasp the solenoid vehicle harness and wiggle wires between solenoid and PCM.
Is a fault indicated?
|Yes |No |
|ISOLATE fault and SERVICE as necessary. RECONNECT all |Unable to duplicate or identify fault at this time. GO to Pinpoint Test |
|components. RERUN Quick Test. |Step Z1 with the following data: EGRVP and EGRVR PIDs and list of |
| |Possible causes. |
HJ40 DTC P0402: OUTPUT ALL DIAGNOSTIC TROUBLE CODES (DTC)
DIAGNOSTIC TROUBLE CODE (DTC) P0402 INDICATES THAT SELF-TEST HAS DETECTED EGR FLOW.POSSIBLE CAUSES:
• Non-seated EGR valve.
• Damaged EGR valve.
• Damaged EGR Valve Position sensor.
• Plugged or pinched EGR valve vacuum hose.
• Plugged or iced EGR Vacuum Regulator solenoid vent.
• EVR circuit shorted to GND.
• Damaged EGR Vacuum Regulator solenoid.
• Damaged PCM.
• Output all Diagnostic Trouble Codes (DTCs).
Is DTC P1409 present?
|Yes |No |
|GO to HJ20. |GO to HJ41. |
HJ41 CHECK EGRVP PID VOLTAGE WITH ENGINE OFF
• KEY ON, ENGINE OFF.
• Access EGRVP PID with a Scan Tool.
Note: The EGR Valve Position sensor voltage with the EGR valve closed is between 0.24 and 0.67 volt.
Does the PID indicate a voltage greater than 0.67 volt?
|Yes |No |
|The EGRVP PID is indicating a voltage greater than the acceptable closed EGR valve voltage. GO to HJ42. |GO to HJ44. |
HJ42 CHECK EGRVP PID VOLTAGE WITH EGR VACUUM HOSE DISCONNECTED
• KEY ON, ENGINE OFF.
• Access EGRVP PID with a Scan Tool.
• Disconnect vacuum hose at EGR valve to allow trapped vacuum to vent (if any).
Does the PID voltage drop to an acceptable level between 0.24 and 0.67 volt?
|Yes |No |
|INSPECT EGR Vacuum Regulator solenoid hoses for a pinched, plugged or damaged hose. If OK, REPLACE EGR Vacuum |GO to HJ43. |
|Regulator solenoid. RECONNECT all components. COMPLETE PCM Reset to clear DTCs. RERUN Quick Test. | |
HJ43 EXERCISE EGR VALVE WITH ENGINE RUNNING
• KEY OFF.
• EGR valve vacuum hose disconnected.
• Connect a hand vacuum pump at the EGR valve.
• Start engine.
• Access EGRVP PID with a Scan Tool.
• Exercise EGR valve by applying 17-34 kPa (5-10 in-Hg) vacuum to the EGR valve and releasing it. Repeat this several times, and in between each time, tap on EGR valve lightly with a small solid object (screwdriver handle) in an attempt to dislodge contamination from valve (if any).
Does the EGRVP PID voltage drop to an acceptable level between 0.24 and 0.67 volts after several attempts at dislodging foreign material?
|Yes |No |
|DTC P0402 was the result of EGR valve binding or |REMOVE EGR valve and EGR Valve Position sensor and INSPECT closely for |
|foreign contamination. SERVICE as necessary. RECONNECT |damage. If none is evident, REPLACE EGR valve. RECONNECT all components. |
|all components. COMPLETE PCM Reset to clear DTCs. RERUN|COMPLETE PCM Reset to clear DTCs. RERUN Quick Test. If DTC is still |
|Quick Test. |present, REPLACE EGR Valve Position sensor. |
HJ44 CHECK EGRVP PID VOLTAGE WITH ENGINE RUNNING
• KEY ON, ENGINE RUNNING.
• Access EGRVP PID with a Scan Tool.
Note: The EGR Valve Position sensor voltage with the EGR valve closed is between 0.24 and 0.67 volt.
Does the EGRVP PID indicate a voltage greater than 0.67 volt with the engine running at idle?
|Yes |No |
|This indicates that the fault is in the vacuum control side of the EGR |The fault that produced DTC P0402 is intermittent. GO to|
|system. GO to HJ45. |HJ46. |
HJ45 CHECK EGR VACUUM REGULATOR SOLENOID
• KEY OFF.
• Remove the EGR Vacuum Regulator solenoid vent cap and inspect the vent for plugging.
• Verify that the EGR Vacuum Regulator solenoid hoses are installed and routed properly.
Are the solenoid vacuum hoses and vent OK?
|Yes |No |
|REPLACE the EGR Vacuum Regulator solenoid. RECONNECT all components. COMPLETE|SERVICE as necessary. COMPLETE PCM Reset to clear |
|PCM Reset to clear DTCs. RERUN Quick Test. |DTCs. RERUN Quick Test. |
HJ46 CHECK EGR SYSTEM FOR INTERMITTENT FAULT
• KEY OFF.
• Disconnect EGR valve vacuum hose.
• Connect a hand vacuum pump at the EGR valve.
• Start engine.
• Access EGRVP PID with a Scan Tool.
• Exercise EGR valve by applying 17-34 kPa (5-10 in-Hg) vacuum to the EGR valve and releasing it. Repeat this several times. On a functioning system, the EGRVP PID voltage will be between 0.24 and 0.67 volt each time the vacuum is released. As an indication of a fault, look for the voltage to hang up above 0.67 volt after vacuum is released.
Does the EGRVP PID voltage drop to an acceptable level, between 0.24 and 0.67 volt each time the vacuum is released?
|Yes |No |
|RECONNECT EGR valve vacuum hose. GO to |ISOLATE fault and SERVICE as necessary. RECONNECT all components. COMPLETE PCM Reset |
|HJ47. |to clear DTCs. RERUN Quick Test. |
HJ47 CHECK FOR INTERMITTENT EGR VALVE POSITION SENSOR AND EGR VACUUM REGULATOR SOLENOID
• KEY ON, ENGINE RUNNING.
• Access EGRVP PID with a Scan Tool. The PID voltage must read between 0.24 and 0.67 volt with engine at idle.
• Observe the EGRVP PID voltage to read greater than 0.67 volt as an indication of a fault while performing the following:
• Lightly tap on the EGR Valve Position sensor and connector.
• Grasp the EGR Valve Position sensor vehicle harness and wiggle wires between the sensor and PCM.
• Lightly tap on the EGR Vacuum Regulator solenoid vehicle harness connector.
• Grasp the EGR Vacuum Regulator solenoid vehicle harness and wiggle wires between the solenoid and PCM.
Is a fault indicated?
|Yes |No |
|ISOLATE fault and SERVICE as necessary. RECONNECT all |Unable to duplicate or identify fault at this time. GO to |
|components. COMPLETE PCM Reset to clear DTCs. RERUN Quick Test. |Pinpoint Test Step Z1 with the following data: EGRVP and EGRVR |
| |PIDs and list of Possible causes. |
Exhaust Gas Recirculation (EGR) System Monitor — Differential Pressure Feedback EGR
|1997 PCED On Board Diagnostics II A |SECTION 1A: Description and Operation |
Exhaust Gas Recirculation (EGR) System Monitor— Differential Pressure Feedback EGR
THE DIFFERENTIAL PRESSURE FEEDBACK EGR SYSTEM MONITOR IS AN ON-BOARD STRATEGY DESIGNED TO TEST THE INTEGRITY AND FLOW CHARACTERISTICS OF THE EGR SYSTEM. THE MONITOR IS ACTIVATED DURING EGR SYSTEM OPERATION AND AFTER CERTAIN BASE ENGINE CONDITIONS ARE SATISFIED. INPUT FROM THE ECT, IAT, TP AND CKP SENSORS IS REQUIRED TO ACTIVATE THE EGR SYSTEM MONITOR. ONCE ACTIVATED, THE EGR SYSTEM MONITOR WILL PERFORM EACH OF THE TESTS DESCRIBED BELOW DURING THE ENGINE MODES AND CONDITIONS INDICATED. SOME OF THE EGR SYSTEM MONITOR TESTS ARE ALSO PERFORMED DURING ON DEMAND SELF-TEST.
1. The Differential Pressure Feedback EGR sensor and circuit are continuously tested for opens and shorts. The monitor looks for the Differential Pressure Feedback EGR circuit voltage to exceed the maximum or minimum allowable limits. The DTCs associated with this test are DTCs P1400 and P1401.
2. The EGR Vacuum Regulator solenoid is continuously tested for opens and shorts. The monitor looks for an EGR Vacuum Regulator circuit voltage that is inconsistent with the EGR Vacuum Regulator circuit commanded output state. The DTC associated with this test is DTC P1409.
3. The test for a stuck open EGR valve or EGR flow at idle is continuously performed whenever at idle (TP sensor indicating closed throttle). The monitor compares the Differential Pressure Feedback EGR circuit voltage at idle to the Differential Pressure Feedback EGR circuit voltage stored during key on engine off to determine if EGR flow is present at idle. The DTC associated with this test is DTC P0402.
4. The Differential Pressure Feedback EGR sensor upstream hose is tested once per drive cycle for disconnect and plugging. The test is performed with EGR valve closed and during a period of acceleration. The PCM will momentarily command the EGR valve closed. The monitor looks for the Differential Pressure Feedback EGR sensor voltage to be inconsistent for a no flow voltage. A voltage increase or decrease during acceleration while the EGR valve is closed may indicate a fault with the signal hose during this test. The DTC associated with this test is DTC P1405.
5. The EGR flow rate test is performed during a steady state when engine speed and load are moderate and EGR Vacuum Regulator duty cycle is high. The monitor compares the actual Differential Pressure Feedback EGR circuit voltage to a desired EGR flow voltage for that state to determine if EGR flow rate is acceptable or insufficient. This is a system type test and may trigger a DTC for any fault causing the EGR system to fail. The DTC associated with this test is DTC P0401.
6. DTC P1408 is similar to P0401 but performed during KOER Self-Test conditions.
7. The MIL is activated after one of the above tests fail on two consecutive drive cycles.
|[pic] |
|Figure 15: EGR System Monitor - Differential Pressure Feedback EGR |
|Click to Enlarge |
|Trouble Code: P1151 (4.2L V6 VIN 2 Auto) |Print this code data[pic] |
|Lack of HO2S-21 Switching, HO2S Signal Low Input | |
Number of Trips to Set Code: 2
OBD II Monitor Type: CCM Details
Indicators: MIL Details
Trouble Code Conditions:
DTC P0300-P0310 not set, engine started, engine running in closed loop, and the PCM detected the HO2S-21 was not switching (i.e., the HO2S-21 indicated a lean A/F mixture).
Possible Causes:
• Air intake system leaking, vacuum hoses leaking or damaged
• Air leaks located after the MAF sensor mounting location or in the PCV system
• Base engine mechanical fault (i.e., compression, valve timing)
• HO2S circuits wet or oily, corroded, or poor terminal contact
• HO2S signal circuit open, shorted to ground, shorted to power, or the sensor has failed
• Low fuel pressure or vehicle driven until it was out of fuel
Are DTCs P1131 or P1151 present?
|Yes |No |
|REMOVE jumper. GO to |REMOVE jumper. RECONNECT HO2S. DISCONNECT PCM. INSPECT both ends of connector for damaged or pushed out |
|HA75. |pins, moisture, corrosion, loose pins. SERVICE as necessary. If OK, REPLACE PCM. RERUN KOER Self-Test. |
HA75 HO2S CHECK
• KEY OFF.
• Suspect HO2S disconnected.
• Connect digital multimeter to HO2S Signal circuit and HO2S SIG RTN at the HO2S sensor connector.
• Disconnect vacuum hose from vacuum tree.
• Start engine and run at 2000 rpm.
Does the voltage reading indicate less than 0.4 volt within 30 seconds?
|Yes |No |
|RECONNECT vacuum hose and HO2S. GO to HA76. |REPLACE HO2S. RECONNECT vacuum hose. RERUN Quick Test. |
HA76 MONITOR HO2S (PID) FOR NORMAL SWITCHING
• KEY ON, ENGINE RUNNING.
• Engine at operating temperature.
Note: HO2S displayed as O2S on Scan Tool.
• Access HO2S PID for suspect HO2S using Scan Tool.
• Access HO2S PID while wiggling, bending, and shaking small sections of the Electronic Engine Control harness from the PCM to the HO2S.
Did the HO2S voltage stay high (greater than 0.45 volt) or low (less than 0.45 volt)?
|Yes |No |
|ISOLATE cause of lack of HO2S switches and service. COMPLETE PCM Reset to clear DTCs. RERUN Quick Test. |GO to HA77. |
HA77 TEST DRIVE WHILE MONITORING HO2S PID FOR NORMAL SWITCHING
NOTE: THIS TEST STEP REQUIRES AN OBSERVER TO MONITOR PID FOR PROPER OPERATION.
• Scan Tool still attached.
• Access HO2S PID.
• While observer views PID, test drive vehicle under different road conditions in an attempt to simulate the original fault.
Does HO2S appear to switch properly?
|Yes |No |
|UNABLE to duplicate fault. COMPLETE PCM Reset to clear DTCs. Testing |REPLACE HO2S. COMPLETE PCM Reset to clear DTCs. RERUN Quick|
|complete at this time. |Test. |
HA80 DTCS P1137, P1138, P1157 AND/OR P1158 LACK OF DOWNSTREAM HO2S SWITCHING
KEY ON, ENGINE RUNNING (KOER) DIAGNOSTIC TROUBLE CODES (DTCS) P1137, P1138, P1157 AND P1158 CAN ONLY BE RETRIEVED DURING KOER SELF-TEST WHEN THE FUEL CONTROL IS RAMPED RICH AND LEAN AND MONITORED FOR A VOLTAGE CHANGE ON THE DOWNSTREAM HO2S.POSSIBLE CAUSES:
• Wiring Concerns
• Pinched, shorted, and corroded wiring and pins
• Other Concerns
• Exhaust leaks
• Inoperative PCM
• Contaminated or damaged sensor
Are any of the above concerns present?
|Yes |No |
|SERVICE as necessary. RERUN Quick Test. |GO to HA81. |
HA81 CHECK EXHAUST SYSTEM FOR LEAKS
NOTE: ANY EXHAUST LEAKS BETWEEN THE ENGINE AND THE END OF THE CATALYST CAN CAUSE THESE DTCS.
• Key off.
• Place vehicle on a hoist, transmission in PARK, emergency brake applied, raise vehicle.
• Inspect the following:
• Exhaust flanges for leaks.
• HO2S torque.
• Check for punctures and cracks in catalyst and pipes leading to them.
Are there any exhaust leaks?
|Yes |No |
|REPLACE or SERVICE as required. RERUN Quick Test. |GO to HA82. |
HA82 CHECK HO2S CIRCUIT
• KEY OFF.
• PCM connected to vehicle harness.
• Suspect HO2S connected to vehicle harness.
• Scan Tool connected.
• Key on, engine off.
Note: HO2S displayed as O2S on Scan Tool.
• Access the correct HO2S PID.
P1137, P1138HO2S-1235 and 91P1157, P1158HO2S-2261 and 91
Is the voltage greater than 1.60 volts?
|Yes |No |
|REPLACE HO2S. RERUN Quick Test. |GO to HA83. |
HA83 CHECK HO2S HARNESS CIRCUIT FOR SHORT TO VPWR AND GROUND
• KEY OFF.
• Disconnect Scan Tool from DLC.
• Breakout box installed, PCM disconnected. Inspect both ends of connector for damaged or pushed out pins, moisture, corrosion and loose pins. Service as necessary.
• HO2S disconnected.
• Measure the resistance between HO2S SIG Test Pin and SIG RTN Test Pin at the breakout box.
• Measure the resistance between HO2S SIG Test Pin and VPWR and VREF Test Pin at the breakout box.
• Measure the resistance between HO2S Signal Test Pin and PWR GND Test Pin at the breakout box.
• HO2S-12 SIG = Test Pin 35
• HO2S-22 SIG = Test Pin 61
• HO2S SIG RTN = Test Pin 91
• PWR GND = Test Pins 24 and 103
• VPWR = Test Pins 71 and 97
• VREF = Test Pin 90
Is resistance greater than 10,000 ohms?
|Yes |No |
|GO to HA84. |SERVICE short in harness. RERUN Quick Test. |
HA84 CHECK RESISTANCE OF HO2S AND HO2S GROUND CIRCUITS
• KEY OFF.
• Breakout box installed, PCM disconnected.
• Disconnect suspect HO2S from harness.
• Measure the resistance between HO2S Signal Test Pin at the breakout box and the HO2S vehicle harness connector. Record readings.
• Measure resistance between SIG RTN Test Pin at the breakout box and HO2S SIG RTN vehicle harness connector. Record readings.
• HO2S-12 SIG = Test Pin 35
• HO2S-22 SIG = Test Pin 61
• HO2S SIG RTN = Test Pin 91
Is the resistance reading less than 5.0 ohms?
|Yes |No |
|REPLACE PCM. REMOVE breakout box. RECONNECT all components. |SERVICE open circuit in harness. REMOVE breakout box. RECONNECT all |
|RERUN Quick Test. |components. RERUN Quick Test. |
HA90 KOER DTC P1127
KEY ON, ENGINE RUNNING (KOER) DIAGNOSTIC TROUBLE CODE (DTC) P1127 INDICATES THE HO2S HEATER(S) WERE NOT ON DURING KOER SELF-TEST AND TESTING OF THE HO2S DID NOT OCCUR. THE HO2S HEATERS ARE TURNED ON AND OFF WHEN CERTAIN TEMPERATURES ARE REACHED. THE HO2S HEATERS ARE ACTIVATED BASED ON EXHAUST TEMPERATURE MODELING, WHICH ALLOWS UPSTREAM HEATERS TO BE ENERGIZED INDEPENDENTLY OF THE DOWNSTREAM HEATERS.POSSIBLE CAUSES:
• Engine not operating long enough prior to performing KOER Self-Test.
• Exhaust system too cool.
• Key off.
• Scan Tool connected.
• Key on, engine off.
• Access HTR11, 12, 21, 22 and monitor PIDs.
Do all PIDs indicate ON?
|Yes |No |
|With engine still running, PERFORM KOER Self-Test. |OPERATE engine until all PIDs indicate ON. PERFORM KOER Self-Test. |
HA100 KOER DTC P1128 AND P1129
KEY ON, ENGINE RUNNING (KOER) DIAGNOSTIC TROUBLE CODES (DTCS) P1128 AND P1129 INDICATE THAT DURING KOER TESTING, EITHER THE UPSTREAM OR THE DOWNSTREAM OR BOTH HO2S SIGNALS ARE SWAPPED FROM BANK TO BANK.
• P1128 refers to the upstream HO2S.
• P1129 refers to the downstream HO2S.
Possible causes:
• Crossed HO2S harness connectors.
• Crossed wiring at HO2S harness connectors.
• Crossed HO2S wiring at PCM 104-pin harness connector.
• Key off.
• Visually inspect vehicle HO2S harness connector(s) for any crossed or stretched wires or wire harnesses not mounted properly.
Are there any indications of crossed connectors or wires?
|Yes |No |
|SERVICE as necessary. RERUN Quick Test. |GO to HA101. |
HA101 VERIFY PROPER HO2S SIGNAL PIN LOCATION
• KEY OFF.
• PCM disconnected, breakout box installed.
• Disconnect both of the suspect HO2S sensors from the vehicle harness connector.
• P1128 = HO2S 11/21 Upstream
• P1129 = HO2S 12/22 Downstream
• Use the DTC and the chart to measure the resistance between the breakout box and the HO2S harness vehicle connectors.
• HO2S-11-Test=Pin 60
• HO2S-21-Test=Pin 87
• HO2S-12-Test=Pin 35
• HO2S-22-Test=Pin 61
Is the resistance less than 5.0 ohms?
|Yes |No |
|HO2S SIG circuit is OK. REMOVE breakout box. |CONNECT HO2S connector to proper HO2S or RELOCATE HO2S signal pins in the PCM|
|RECONNECT PCM. RERUN Quick Test. |104-pin harness connector or HO2S harness connector. RERUN Quick Test. |
Note: Check for any other key on, engine running DTCs which can cause the Misfire DTC.
Are any additional key on, engine running DTCs displayed on the Scan Tool?
If DTCs P1131, P1137, P1151 or P1157 are present, GO to HD8.
HD8 CHECK RESISTANCE OF FUEL INJECTOR(S) AND HARNESS
• KEY OFF.
• Disconnect PCM. Inspect for damaged or pushed out pins, corrosion and loose wires. Service as necessary.
• Install breakout box, leave PCM disconnected.
• Measure resistance between suspect fuel injector test pin and Test Pin 71 or 97 at the breakout box. Refer to the list in HD1.
Is the resistance between 11.0-18.0 ohms?
|Yes |No |
|Fuel injector and harness resistance is OK. GO to HD9. |GO to Pinpoint Test Step H56 to diagnose fuel injectors. |
HD9 CHECK INJECTOR DRIVER SIGNAL
NOTE: THIS STEP REQUIRES A STANDARD 12 VOLT TEST LAMP. A PROPERLY OPERATING SYSTEM WILL SHOW A DIM GLOW ON THE TEST LAMP.
• Key off.
• Breakout box installed.
• Connect PCM to breakout box.
• Connect Test Lamp between Test Pin 71 or 97 and suspect injector test pin.
• Start engine.
Does test lamp have a dim glow while running engine?
|Yes |No |
|GO to HD10. |No light or bright light: REPLACE PCM. REMOVE breakout box. RERUN Quick Test. |
HD10 CHECK FUEL PRESSURE
WARNING: THE FUEL SYSTEM WILL REMAIN PRESSURIZED WHEN ENGINE IS NOT RUNNING. TO PREVENT INJURY OR FIRE, USE CAUTION WHILE WORKING ON THE FUEL SYSTEM.
• Key off.
• Install fuel pressure gauge.
• Start and run engine at idle. Record fuel pressure.
• Increase engine speed to 2500 rpm and maintain for one minute. Note and compare fuel pressure.
Is fuel pressure between 210-310 kPa (30-45 psi)?
|Yes |No |
|GO to HD11. |GO to Powertrain/Fuel System Group in the Service Manual. |
HD11 CHECK ABILITY OF FUEL SYSTEM TO HOLD FUEL PRESSURE
• START AND RUN ENGINE AT IDLE. NOTE FUEL PRESSURE.
• Increase engine speed to 2500 rpm and maintain for one minute.
• Look for fuel leaking at the fuel injector O-ring, fuel pressure regulator and the fuel lines to the fuel charging assembly. Service as necessary.
• Turn engine off.
• Key on, engine off.
Does fuel pressure remain at specification within 16.5 kPa (5 psi) for 60 seconds?
|Yes |No |
|GO to HD12. |GO to Powertrain/Engine or Fuel System Group in the Service Manual to determine which area within the Fuel |
| |Delivery System is at fault. |
HD12 CHECK FUEL INJECTOR FOR FLOW AND LEAKAGE
• REFER TO WARNING, CAUTION AND HANDLING AT THE BEGINNING OF PINPOINT TEST HC TO AVOID FUEL SPILLAGE AND INJURY.
• Verify that the flow rate for each fuel injector is within specification using Injector Flow Tester.
Is flow rate for each fuel injector within specification?
|Yes |No |
|Fuel delivery system is not likely to have caused the Misfire DTC. GO |REPLACE or CLEAN the inoperative fuel injector(s) as |
|to HD20 to diagnose the vacuum system. |required. RERUN Quick Test. |
HD20 CHECK VACUUM SYSTEM
NOTE: SOME VACUUM LEAKS CAN BE HEARD.
• Inspect all vacuum lines for damage, such as pinched lines, cracks, proper routing and assembly.
• Refer to the Electrical and Vacuum Troubleshooting Manual (EVTM) for vacuum service information and repair.
Is the vehicle vacuum system OK?
|Yes |No |
|GO to HD21. |SERVICE the vacuum system. REFER to the Electrical and Vacuum Troubleshooting Manual. RERUN Quick Test. |
HD21 CHECK EVAPORATIVE EMISSION SYSTEM
THE MISFIRE MONITOR CAN BE INFLUENCED BY EVAPORATIVE EMISSION SYSTEM. THE NEXT FOUR PINPOINT TEST STEPS WILL DIAGNOSE THE EVAPORATIVE EMISSION SYSTEM.
• Check the fuel vapor storage canister for fuel saturation.
Is there an excess amount of liquid fuel present in the fuel vapor storage canister?
|Yes |No |
|REPLACE fuel vapor storage canister. RERUN Quick Test. |GO to HD22. CHECK fuel tank vent system. |
HD22 PRESSURE TEST EVAPORATIVE EMISSION SYSTEM
• KEY OFF.
• Install Rotunda Evaporative Emission System Tester 134-00056 or equivalent at the EVAP SERVICE port, if equipped, or the fuel filler cap.
• Follow test instructions from the Tester Kit.
Is evaporative emission system holding pressure?
|Yes |No |
|GO to HD23. |SERVICE as necessary. RERUN Quick Test. |
HD23 CHECK VACUUM IN EVAPORATIVE EMISSION SYSTEM
• CHECK FOR BLOCKAGE/RESTRICTIONS OR CUT HOSES BETWEEN ENGINE VACUUM PORT AND FUEL VAPOR STORAGE CANISTER.
• Check for blockage in fuel tank vent system.
Is there a fault indicated?
|Yes |No |
|REPLACE damaged vacuum hoses, or REMOVE blockage/restrictions. RERUN Quick Test. |For vehicles with EVAP Canister Purge |
| |valve: |
| |GO to HD24. |
| |For vehicles with VMV: |
| |GO to HD26. |
HD24 CHECK EVAP CANISTER PURGE VALVE
THIS PINPOINT TEST STEP WILL VERIFY THE MECHANICAL INTEGRITY OF EVAP CANISTER PURGE VALVE. THE VALVE AND CIRCUIT HAVE BEEN CHECKED ELECTRICALLY AND REPORTED DURING KOEO SELF-TEST.
• Key off.
• Disconnect EVAP Canister Purge valve.
• CAUTION: Observe proper pin orientation.
• Connect 12 volt DC power source to valve.
• Connect positive power source to VPWR circuit and negative lead to EVAP Canister Purge circuit at the EVAP Canister Purge valve harness connector.
• Apply 53 kPa (16 in-Hg) of vacuum to the manifold side of the EVAP Canister Purge valve. Apply power source.
Does the valve open and pass air freely?
|Yes |No |
|Evaporative Emission system is functioning properly. GO to HD25 for Base |REPLACE EVAP Canister Purge valve. RERUN Quick Test.|
|Engine concerns. | |
HD25 CHECK FOR BASE ENGINE CONCERNS
THIS PINPOINT TEST STEP WILL DETERMINE IF THERE ARE ANY BASE ENGINE CONCERNS THAT MAY HAVE CAUSED THE MISFIRE DTC OR DRIVE CONCERN.PERFORM THE FOLLOWING TESTS IN ORDER TO EVALUATE BASE ENGINE INTEGRITY:
• Perform an Engine Compression test.
• Perform Dynamic Valve Train analysis.
• Check Positive Crankcase Ventilation System.
• Check possible leakage points.
• Refer to the Diagnosis and Testing procedures in the Powertrain/Engine Group of the Service Manual for all of the above procedures.
Is any service required?
|Yes |No |
|GO to Powertrain/Engine Group in the Service |The cause of the Misfire DTC is intermittent. To diagnose the Ignition System, |
|Manual, Diagnosis and Testing, to make repairs. |GO to the Intermittent Ignition procedure in Pinpoint Test Step Z50. FOLLOW |
|RERUN Quick Test. |Instructions for using the Rotunda Electronic Ignition System, also known as the|
| |Distributor/less Ignition System Tester (DIST) tool. |
HD26 CHECK FOR VMV HOUSING LEAKS
• KEY OFF.
• VMV electrially connected.
• Install a hand vacuum pump to the fuel vapor port to fuel vapor storage canister on the VMV vacuum at line.
• Apply 53 kPa (16 in-Hg) of vacuum with the vacuum pump.
Does the VMV hold vacuum at room temperature?
|Yes |No |
|GO to HD27. |REMOVE vacuum pump. REPLACE damaged VMV. RECONNECT all components. COMPLETE PCM Reset to clear DTCs. RERUN Quick |
| |Test. |
HD27 CHECK FOR FILTER CONTAMINATION OR DAMAGE ON VMV
• KEY OFF.
• Vacuum line from input vacuum port to intake manifold on the VMV (control vacuum solenoid part of valve) is removed.
• Install a hand held vacuum pump to the open input vacuum port on the VMV.
• Apply 48-52 kPa (10-15 in-Hg) of vacuum to the VMV.
Does the VMV hold vacuum or is the valve very slow to release vacuum to atmosphere?
|Yes |No |
|SERVICE VMV filter. If unable to clean filter or REMOVE blockage to filter, REPLACE |REMOVE vacuum pump. RECONNECT all |
|VMV. RECONNECT all components. COMPLETE PCM Reset to clear DTCs. RERUN Quick Test. |components. GO to HD25. |
HD30 CHECK FOR ADDITIONAL MISFIRE DTCS
DIAGNOSTIC TROUBLE CODE P0300 INDICATES MULTIPLE CYLINDERS ARE MISFIRING OR PCM CANNOT IDENTIFY WHICH CYLINDER IS MISFIRING.POSSIBLE CAUSES:
• Camshaft Position Sensor (CMP)
• Low fuel: less than 1/8 tank
• Stuck open EGR valve
Are any other misfire DTCs present?
|Yes |No |
|GO to HD1. |GO to HD31. |
HD31 CHECK FOR OTHER CONTINUOUS MEMORY DTCS
ARE OTHER CONTINUOUS MEMORY DTCS PRESENT?
|Yes |No |
|Go to Section 4A for Powertrain DTC Charts. PROCEED as required. |GO to HD32. |
HD32 CHECK/COMPARE PID VALUES
• KEY OFF.
• Connect Scan Tool.
• Accessories off (A/C, heater, radio, etc.).
• Start engine and warm to normal operating temperature.
• Access DPFEGR PID with the Scan Tool.
• Key on, engine off.
• Record PID value.
• Start engine, let idle.
• Compare key on, engine off and engine running PID values.
Was engine running DPFEGR PID value within 0.15 volt of key on, engine off value?
|Yes |No |
|DISCONNECT Scan Tool. GO to HD8. |GO to Pinpoint Test Step HE100. |
HD40 CHECK CMP SENSOR OUTPUT
DIAGNOSTIC TROUBLE CODE (DTC) P1309 INDICATES MISFIRE DETECTION MONITOR IS NOT ENABLED.
• Key off.
• Breakout box installed, PCM disconnected.
• Connect digital multimeter between Test Pin 85 (CMP) and Test Pins 51 or 103 (PWR GND) at the breakout box.
• Bump engine in short burst with the starter without starting engine for at least 10 engine revolutions.
Does digital multimeter reading switch between low (less than 2.0 volts DC) and high (greater than 8.0 volts DC)?
|Yes |No |
|Note: A Hall effect type CMP sensor that is installed out of synchronization will produce|REPLACE CMP sensor. REMOVE breakout |
|a DTC. VERIFY the correct installation by referring to the Powertrain/Engine Group in the|box. RECONNECT all components. RERUN |
|Service Manual. If the CMP is installed properly, REPLACE PCM. REMOVE breakout box. |Quick Test. |
|RECONNECT all components. RERUN Quick Test. | |
H40 DTCs P1131, P1151, P1132 AND P1152: UPSTREAM HO2S(S) NOT SWITCHING. DTCs P1130 AND P1150: FUEL SYSTEM NOT SWITCHING AT FUEL TRIM (RICH OR LEAN)
DIAGNOSTIC TROUBLE CODES (DTCS) P1131 BANK 1 (CYLINDER 1) AND P1151 BANK 2 INDICATE THE FUEL/AIR RATIO IS CORRECTING RICH FOR AN OVERLY LEAN CONDITION. THE HO2S VOLTAGE IS LESS THAN 0.45 VOLT. DTCS P1132 BANK 1 (CYLINDER 1) AND P1152 BANK 2 INDICATE THE FUEL/AIR RATIO IS CORRECTING LEAN FOR AN OVERLY RICH CONDITION. THE HO2S VOLTAGE IS GREATER THAN 0.45 VOLT.DTCS P1130 AND P1150 INDICATE THE FUEL CONTROL SYSTEM HAS REACHED MAXIMUM COMPENSATION FOR A LEAN OR RICH CONDITION AND THE HO2S IS NOT SWITCHING.DTC/HO2S REFERENCE LIST
• HO2S-11 = DTCs P1131, P1132 and P1130
• HO2S-21 = DTCs P1151, P1152 and P1150
Possible causes:Fuel system
• Excessive fuel pressure.
• Leaking fuel injector(s).
• Leaking fuel pressure regulator.
• Low fuel pressure or running out of fuel.
• Contaminated fuel injector(s)
Induction system
• Air leaks after the MAF.
• Vacuum leaks (vacuum lines and gaskets).
• Restricted air inlet.
• PCV system.
• Fuel purge system.
• Improperly seated engine oil dipstick.
EGR System
• Leaking gasket.
• Stuck open EGR valve.
• Leaking diaphragm.
Base engine
• Oil overfill.
• Cam timing.
• Cylinder compression.
• Exhaust leaks before or near the HO2Ss.
• Check intake air system for leaks, obstructions and damage.
• Check air cleaner element, air cleaner housing for blockage.
• Verify integrity of the PCV system.
• Check for vacuum leaks.
Are any of the above concerns present?
|Yes |No |
|SERVICE as necessary. COMPLETE PCM Reset to clear DTCs. RERUN Quick Test. |GO to H42. |
H41 DTCs P0172, P0174, P0171 AND P0175: FUEL SYSTEM AT THE CORRECTED FUEL TRIM
DIAGNOSTIC TROUBLE CODES (DTCS) P0171 BANK 1 (CYLINDER 1) AND DTC P0174 BANK 2 INDICATE THE FUEL/AIR RATIO IS TOO LEAN. THE FUEL TRIM SYSTEM IS AT THE RICH CORRECTION LIMIT.DTC P0172 BANK 1 AND DTC P0175 BANK 2 INDICATE THE FUEL/AIR RATIO IS TOO RICH. THE FUEL TRIM SYSTEM IS AT THE LEAN CORRECTION LIMIT.DTCS HO2S REFERENCE LIST:
• HO2S-11 = DTCs P0171 and P0172
• HO2S-21 = DTCs P0174 and P0175
Possible causes:Fuel system
• Excessive fuel pressure.
• Leaking fuel injector(s).
• Leaking fuel pressure regulator.
• Low fuel pressure or running out of fuel.
• Contaminated fuel injector(s).
• Vapor management valve (VMV) leaking.
Induction system
• Air leaks after the MAF.
• Vacuum leaks (vacuum lines and gaskets).
• Restricted air inlet.
• PCV system.
• Fuel purge system.
• Improperly seated engine oil dipstick.
EGR System
• leaking gasket.
• Stuck open EGR valve.
• Leaking diaphragm.
Base engine
• Oil overfill.
• Cam timing.
• Cylinder compression.
• Exhaust leaks before or near the HO2S(s).
• Check intake air system for leaks, obstructions and damage.
• Check air cleaner element, air cleaner housing for blockage.
• Verify integrity of the PCV system.
• Check for vacuum leaks.
Are any of the above concerns present?
|Yes |No |
|SERVICE as necessary. COMPLETE PCM Reset to clear DTCs. RERUN Quick Test. |GO to H42. |
H42 PERFORM KOER SELF-TEST
• KEY OFF.
• Scan Tool connected.
• Disconnect fuel vapor hose from intake manifold and plug fitting at intake manifold.
• Start engine and run at 2000 rpm for 5 minutes and return to idle.
• Perform Key On Engine Running (KOER) Self-Test.
Are any HO2S DTCs P1127, P1128 P1129, P1131, P1132, P1151 or P1152 present?
|Yes |No |
|If DTC(s) P1127, P1128, or P1129 are present, GO to Section 4A, |For Continuous DTCs Only P1130, P1150, P0171, P0174, |
|Powertrain Diagnostic Trouble Code (DTC) Charts and SERVICE those DTCs |P0172 and P0175: |
|first. If DTC(s) P0131 or P0151 are present in Continuous Memory, |GO to H52. |
|SERVICE DTC P0131 or P0151 in the order they are displayed. GO to H27. |If DTC(s) P1132 and/or P1152 are no longer present, |
|DTCs P1131, P1130, or P1151, P1150: |RECONNECT fuel vapor line. |
|GO to H43. |Escort/Tracer, Mustang, Thunderbird/Cougar and |
|DTCs P1132, P1130, or P1152, P1150: |Ranger/Aerostar with EVAP canister purge valve: |
|GO to H49. |GO to HW18. |
| |Contour/Mystique, Continental, 5.8L F-Series/E-Series and|
| |7.5L F-Series: |
| |GO to HW10. |
| |All other EVAP systems: |
| |GO to HX49. |
| |All others without reoccuring DTCs: |
| |The fault that produced the DTC is an intermittent. GO to|
| |Pinpoint Test Step Z1 with the following data: HO2S-11, |
| |21 PIDs and list of Possible causes. |
H43 HO2S CIRCUIT TEST (WITH LEAN DTCs)
• KEY OFF.
• Scan Tool connected.
• Disconnect the HO2S related to the DTC. Inspect for damaged or pushed out pins, water, corrosion, loose wires. Service as necessary.
• Key on, engine off.
• Access the correct HO2S PID.
Note: If a spark occurs, remove jumper and go to Pinpoint Test Step H47(check fuse in the heater circuit).
• Jumper the HO2S Signal circuit to the HO2S Heater VPWR circuit at the HO2S vehicle harness connector.
Is the reading 1.30 volts or greater?
|Yes |No |
|CHECK SIG RTN circuit. GO to H44. |An open or short to ground exists in the vehicle harness or PCM. GO to H46. |
H44 CHECK SIGNAL RETURN CIRCUIT FOR SHORTS AND OPENS
• KEY OFF.
• Install breakout box. PCM connected.
• Measure the resistance between the HO2S SIG RTN terminal at the HO2S vehicle harness connector and the battery ground terminal.
Is the resistance reading less than 5.0 ohms?
|Yes |No |
|REMOVE breakout box. GO to H52. |CHECK wiring. GO to H45. |
H45 CHECK HO2S SIGNAL RETURN CIRCUIT IN VEHICLE HARNESS
• BREAKOUT BOX INSTALLED. PCM DISCONNECTED.
• Measure the resistance between the HO2S SIG RTN terminal at the HO2S vehicle harness connector and the SIG RTN test pin at the breakout box.
Is the resistance reading less than 5.0 ohms?
|Yes |No |
|REMOVE breakout box. REPLACE PCM. RERUN Quick Test. |SERVICE open circuit. REMOVE breakout box. RERUN Quick Test. |
H46 CHECK RESISTANCE OF HO2S AND HO2S GROUND CIRCUITS
• KEY OFF.
• Disconnect PCM. Inspect both ends of connector for bent or pushed out pins, corrosion or other damage. Service as necessary.
• Install breakout box. Leave PCM disconnected.
• Disconnect suspect HO2S from harness. Inspect both ends of connector for damaged or pushed out pins, moisture, corrosion, loose pins. Service as required.
• Measure the resistance between HO2S Signal Test Pin at the breakout box and the HO2S vehicle harness connector. Use the Pin assignment below and record the reading:
• HO2S-11 SIG = Test Pin 60
• HO2S-21 SIG = Test Pin 87
• HO2S SIG RTN = Test Pin 91
Is the resistance reading less than 5.0 ohms?
|Yes |No |
|GO to H47. |SERVICE open circuit. REMOVE breakout box. RECONNECT PCM and HO2S. RERUN Quick Test. |
H47 CHECK HO2S CIRCUIT WIRING HARNESS FOR SHORT TO GROUND
• KEY OFF.
• Breakout box installed, PCM disconnected.
• HO2S disconnected.
• Measure resistance between the HO2S Signal Test Pin and Test Pins 24, 51, 77, 103 (PWR GND) and 91 (SIG RTN) at the breakout box.
Is each resistance greater than 10,000 ohms?
|Yes |No |
|GO to H48. |SERVICE short circuit. REMOVE breakout box. RECONNECT PCM and HO2S. RERUN Quick Test. |
H48 CHECK HO2S FOR SHORT TO GROUND
• KEY OFF.
• Breakout box installed, PCM disconnected.
• Reconnect HO2S.
• Measure resistance between PWR GND and SIG RTN Test Pins and HO2S Signal Test Pin at the breakout box:
• HO2S-11 SIG = Test Pin 60
• HO2S-21 SIG = Test Pin 87
• HO2S GND = Test Pin 24 and 103
• HO2S SIG RTN = Test Pin 91
Is resistance greater than 10,000 ohms?
|Yes |No |
|REMOVE breakout box. RECONNECT HO2S. REPLACE PCM. RERUN Quick |REPLACE HO2S. REMOVE breakout box. RECONNECT PCM. RERUN Quick |
|Test. |Test. |
H49 HO2S CIRCUIT CHECK (FOR RICH DTCS)
• KEY OFF.
• Disconnect the HO2S related to the DTC received. Inspect for damaged or pushed out pins, corrosion and loose wires. Service as necessary.
• Scan Tool connected.
• Key on.
• Access the HO2S PID(s).
Is the reading 0.2 volt or less?
|Yes |No |
|GO to H51. |A short to power exists. GO to H50. |
H50 CHECK FOR SHORTS TO VOLTAGE SOURCE IN THE HARNESS CIRCUIT
• KEY OFF.
• Disconnect Scan Tool from DLC.
• Suspect sensor disconnected.
• Disconnect PCM. Inspect for damaged or pushed out pins, corrosion and loose wires. Service as necessary.
• Install breakout box, leave PCM disconnected.
• Use the following list to measure the resistance between the appropriate test pins at the breakout box:
• DTC P1130, P1132=HO2S-11
• Test Pin 60 and Test Pins 71, 93 and 97.
• DTC P1150, P1152=HO2S-21
• Test Pin 87 and Test Pins 71, 94 and 97.
Is the resistance greater than 10,000 ohms?
|Yes |No |
|REMOVE breakout box. REPLACE PCM. RERUN Quick |REPLACE HO2S. SERVICE short to power. REMOVE breakout box. RECONNECT all |
|Test. |components. RERUN Quick Test. |
H51 CHECK FOR HO2S SIGNAL SHORTED TO HO2S HEATER CIRCUIT IN THE SENSOR
• KEY OFF.
• Suspect HO2S sensor connected.
• Scan Tool connected.
• Key on, engine off.
Note: HO2S displayed as O2S on Scan Tool.
• Access HO2S PID corresponding to DTCs received.
Is the HO2S voltage greater than 0.45 volt?
|Yes |No |
|REPLACE HO2S. RECONNECT all components. RERUN Quick Test. |RECONNECT all components. GO to H52. |
H52 CHECK FUEL PRESSURE
WARNING: THE FUEL SYSTEM IS PRESSURIZED WHEN THE ENGINE IS NOT RUNNING. TO PREVENT INJURY OR FIRE, USE CAUTION WHEN WORKING ON THE FUEL SYSTEM. BECOME FAMILIAR WITH THE WARNING CAUTION AND NOTE IN PINPOINT TEST HC BEFORE SERVICING.
• Key off.
• Install fuel pressure gauge.
• Verify vacuum source to fuel pressure regulator.
• If engine will start:
• Start engine and idle. Record fuel pressure.
• Increase engine speed to 2500 rpm and maintain for one minute. Record fuel pressure.
• No Start:
• Cycle key on and off several times. Record fuel pressure.
Is the fuel pressure between 310-415 kPa (45-60 psi) for (2.5L) Contour/Mystique or 207-310 kPa (30-45 psi) for all others?
|Yes |No |
|Fuel system is capable of required fuel pressure. GO to H53. |Probe: |
| |Fuel pressure out of specification. |
| |GO to Pinpoint Test KN1. |
| |All others: |
| |GO to Pinpoint Test HC1. |
H53 CHECK SYSTEM ABILITY TO HOLD FUEL PRESSURE
• FUEL PRESSURE GAUGE INSTALLED.
• Cycle key on and off several times.
• Verify there are no external leaks (service as necessary).
Does the fuel pressure remain within 34 kPa (5 psi) of the highest reading after one minute?
|Yes |No |
|For Continuous DTCs P1130, P1150, P0171, P0172, P0174 and P0175: |Excessive pressure loss. GO to Pinpoint Test Step HC4. |
|GO to H54. | |
|For No Starts: | |
|GO to H55. | |
|For HO2S DTCs displayed with misfire DTCs: GO to H56. | |
|Flexible Fuel Taurus: | |
|GO to H56. | |
|All other DTCs: | |
|GO to H60. | |
H54 CHECK SYSTEM ABILITY TO HOLD FUEL PRESSURE WITH KEY ON
• FUEL PRESSURE GAUGE INSTALLED.
• Cycle key on then off several times.
• Turn key on and engine off, monitor fuel pressure gauge.
Does the fuel pressure remain within 34 kPa (5 psi) of the highest reading after 10 seconds?
|Yes |No |
|For Continuous DTCs P1130, P1150, P0171 and P0174: |For DTCs P0172 and P0175: |
|GO to H56. |GO to H58. |
H55 CHECK ABILITY OF FUEL INJECTOR(S) TO DELIVER FUEL
• PRESSURE GAUGE INSTALLED.
• Cycle key several times.
• Locate and disconnect the Inertia Fuel Shutoff (IFS) Switch.
• Monitor pressure gauge while cranking the engine for at least five seconds.
Was there a pressure drop greater than 34 kPa (5 psi) while cranking the engine?
|Yes |No |
|The Electronic Engine Control System is not the cause of the no start. REMOVE the fuel |REMOVE fuel pressure gauge. RECONNECT IFS|
|pressure gauge. RECONNECT the IFS switch. REFER to Symptom Charts, Symptom Charts, for |switch. GO to H56. |
|further diagnosis. | |
H56 CHECK RESISTANCE OF FUEL INJECTOR(S) AND HARNESS
• KEY OFF.
Note: This erases Continuous Memory DTCs.
• Disconnect PCM. Inspect for damaged or pushed out pins, corrosion and loose wires. Service as necessary.
• Install breakout box, leave PCM disconnected.
Note: If misfire DTCs are displayed with the Fuel Control DTCs, use the misfire DTCs to determine the fuel injector circuits requiring testing.
• Measure resistance between suspect fuel injector Test Pin(s) and Test Pin 71/97 (VPWR) at the breakout box using the chart below.
FUEL INJECTOR TEST PINS175699210177237489841009685731042
Is the resistance between 11.0-18.0 ohms?
|Yes |No |
|Fuel injector and harness resistance is OK. GO to H59. |GO to H57. |
H57 CHECK RESISTANCE OF FUEL INJECTOR HARNESS
• KEY OFF.
• Breakout box installed, PCM disconnected.
• Disconnect fuel injector harness connector at the suspect fuel injector.
• Measure the resistance between Test Pin 71/97 (VPWR) at the breakout box and the VPWR pin at the fuel injector harness connector.
• Measure resistance between the Fuel Injector Test Pin(s) at the breakout box and the Fuel Injector Signal Pin at the fuel injector connector. (Refer to chart in H56 for Fuel Injector Pin location.)
Is each resistance less than 5.0 ohms?
|Yes |No |
|GO to H58. |SERVICE open harness circuit. REMOVE breakout box. RECONNECT PCM and fuel injectors. RERUN Quick Test. |
H58 CHECK FUEL INJECTOR HARNESS CIRCUIT FOR SHORT TO POWER OR GROUND
• KEY OFF.
• Breakout box installed, PCM disconnected.
• Suspect fuel injector harness disconnected.
• Measure resistance between the fuel injector Test Pin(s) and Test Pin 71 or 97 (VPWR), 24 and 103 (PWR GND) at the breakout box (refer to chart in H56).
• Measure the resistance between the Fuel Injector Test Pin(s) at the breakout box and chassis ground.
Is each resistance greater than 10,000 ohms?
|Yes |No |
|GO to H59. |SERVICE short circuit. REMOVE breakout box. RECONNECT PCM and all fuel injector(s). RERUN Quick Test. |
H59 CHECK INJECTOR DRIVER SIGNAL
THIS TEST REQUIRES A STANDARD 12 VOLT TEST LAMP.
• Key off.
• Breakout box installed.
• Connect PCM to breakout box.
• Connect test lamp between Test Pin 71/97 (VPWR) and suspect fuel injector Test Pin(s) (refer to chart in H56).
Note: Properly operating system will show a dim glow at idle on the test lamp.
• Crank or start engine.
Does test lamp have a dim glow while cranking or running engine?
|Yes |No |
|REMOVE breakout box. RECONNECT PCM. GO to H60. |No light/Continuous bright light. REPLACE PCM. REMOVE breakout box. RERUN |
| |Quick Test. |
H60 FLOW TEST FUEL INJECTOR(S)
• USE THE ROTUNDA INJECTOR TESTER, SBDS® INJECTOR TESTER OR EQUIVALENT TO FLOW TEST THE FUEL INJECTORS ACCORDING TO THE INSTRUCTIONS FOR THE FUEL INJECTOR TESTER.
Is the leakage and flow within specification?
|Yes |No |
|DTCs P0171, P0174: |REPLACE fuel injector. COMPLETE PCM Reset to |
|GO to H62. |clear DTCs. RERUN Quick Test. |
|DTCs P0172 and P0175: | |
|The fault that produced the DTC is an intermittent. GO to Pinpoint Test Step Z1| |
|with the following data: SF1, SF2, LFT1, LFT2 PIDs and list of Possible causes.| |
|For DTCs P1130 and P1150: | |
|GO to H62. | |
|For DTCs P1131 and P1151: | |
|GO to H61. | |
|For DTCs P1132 and P1152: | |
|GO to H65. | |
H61 CHECK FOR SECONDARY AIR INTRUSION
NOTE: IF THE VEHICLE IS NOT EQUIPPED WITH SECONDARY AIR INJECTION SYSTEM, GO TO H62.AN HO2S ALWAYS LEAN CONDITION CAN BE CAUSED BY:
• Leak in hoses from Secondary Air Injection pump to engine.
• Secondary Air diverted upstream of HO2S.
• Key off.
• Disconnect Secondary Air Injection hose(s) from engine and plug engine side of secondary air injection system.
• Key on, engine running and at operating temperature.
• Activate Key On, Engine Running (KOER) Self-Test.
Are DTC(s) P1131 or P1151 present?
|Yes |No |
|RECONNECT secondary air injection hose and GO to|Cause of DTC(s) is in the Secondary Air Injection System. GO to HM7 for |
|H62. |Secondary Air Injection System diagnostics. |
H62 INSPECT INDUCTION SYSTEM FOR AIR LEAKS
• INSPECT THE FOLLOWING AREAS FOR SIGNS OF AIR LEAKS:
• Inlet tube(s) from air cleaner to the throttle body.
• Gaskets which seal the upper and lower intake manifold.
• Vacuum hoses and lines for cracks and proper connections.
• PCV system.
Are there any signs of leaks or damage?
|Yes |No |
|SERVICE as necessary. COMPLETE PCM Reset to |CONTINUOUS DTCs P0171, P0174, P1130 or P1150: |
|clear DTCs. RERUN Quick Test. |The fault that produced the DTC is an intermittent. GO to Pinpoint Test Step Z1 with|
| |the following data: SF1, SF2, LFT1, LFT2, HO2S-11 and HO2S-21 PIDs and a list of |
| |Possible causes. |
| |DTCs P1131 and P1130 or P1151 and P1150: |
| |GO to H63. |
H63 CHECK CYLINDER COMPRESSION
NOTE: USE THE MISFIRE DTC(S) DISPLAYED ON PRIOR DTC RETRIEVAL TO DETERMINE WHICH CYLINDER'S COMPRESSION TO CHECK.
• Check cylinder compression. Refer to Powertrain/Engine Group, Base Engine/Engine—Service Section in the Service Manual.
Are cylinder compression readings within specification?
|Yes |No |
|For DTCs P1131, P1130, P1151 and P1150: |SERVICE as necessary. COMPLETE PCM Reset to clear DTCs. RERUN Quick Test. |
|GO to H64. | |
|For DTCs P1132 and P1152: | |
|GO to H65. | |
|Misfire DTCs displayed with fuel control DTCs: | |
|GO to HD20. | |
H64 CHECK HO2S ABILITY TO GENERATE A VOLTAGE GREATER THAN 0.5 VOLT
ANY VACUUM OR AIR LEAKS CAN CAUSE DTCS P1131, P1151, P1130 AND P1150.POSSIBLE CAUSES:
• Leaking vacuum actuators.
• Engine sealing (Intake and IAC).
• EGR system (valve).
• PCV system (hose and valve).
• Unmetered air leaks between throttle body and Mass Air Flow (MAF) sensor assembly.
• Silicone contaminated HO2S.
• Key off.
• Inspect HO2S harness for chafing, burned out wires or other damage and service as necessary.
• Disconnect the suspect HO2S from vehicle harness.
• Connect digital multimeter to the HO2S Signal and HO2S SIG RTN or HO2S GND at the HO2S sensor connector.
• Run engine at 2000 rpm for three minutes.
• Rerun KOER Self-Test and monitor HO2S voltage.
Is the voltage greater than 0.5 volt during or at the end of Self-Test?
|Yes |No |
|GO to H70. |REPLACE HO2S. RERUN Quick Test. |
H65 ATTEMPT TO GENERATE DTCS P1131 AND P1151
• KEY OFF.
• HO2S disconnected.
• Jumper HO2S Signal at the HO2S harness vehicle connector to the battery negative post.
• Activate Key On Engine Running (KOER) Self-Test.
Are DTCs P1131 or P1151 present?
|Yes |No |
|REMOVE jumper. GO to |REMOVE jumper. RECONNECT HO2S. DISCONNECT PCM. INSPECT both ends of connector for damaged or pushed out |
|H66. |pins, moisture, corrosion, loose pins and SERVICE as necessary. If OK, REPLACE PCM. RERUN KOER Self-Test.|
H66 HO2S CHECK
• KEY OFF.
• Suspect HO2S disconnected.
• Connect digital multimeter to HO2S SIG circuit and HO2S SIG RTN at the HO2S sensor connector.
• Disconnect vacuum hose from vacuum tree.
• Start engine and run at 2000 rpm.
Does the voltage reading indicate less than 0.4 volt within 30 seconds?
|Yes |No |
|RECONNECT vacuum hose and HO2S. GO to H70. |REPLACE HO2S. RECONNECT vacuum hose. RERUN Quick Test. |
H70 MONITOR HO2S (PID) FOR PROPER SWITCHING
• KEY ON, ENGINE RUNNING.
• Engine at operating temperature.
Note: HO2S displayed as O2S on Scan Tool.
• Monitor suspect HO2S PID using Scan Tool.
• Access HO2S PID while wiggling, bending, and shaking small sections of the Electronic Engine Control harness from the PCM to the HO2S.
Did the HO2S voltage stay high (greater than 0.45 volt) or low (less than 0.45 volt)?
|Yes |No |
|ISOLATE cause of lack of HO2S switches and service. COMPLETE PCM Reset to clear DTCs. RERUN Quick Test. |GO to H71. |
H71 TEST DRIVE WHILE MONITORING HO2S PID FOR PROPER SWITCHING
NOTE: THIS TEST STEP REQUIRES AN OBSERVER TO MONITOR PID FOR PROPER OPERATION.
• Scan Tool still attached.
• Access HO2S PID.
• While observer views PID, test drive vehicle under different road conditions in an attempt to simulate the original fault.
Does HO2S appear to switch properly?
|Yes |No |
|UNABLE to duplicate fault. COMPLETE PCM Reset to clear DTCs. Testing |REPLACE HO2S. COMPLETE PCM Reset to clear DTCs. RERUN Quick|
|complete at this time. |Test. |
H80 DTCS P0136 AND P0156 MONITOR DOWNSTREAM HO2S OUTPUT VOLTAGE FOR ACTIVITY. DTCS P1137, P1138, P1157 AND/OR P1158 INDICATE LACK OF HO2S SWITCHING
DTC P0136 AND P0156 INDICATE THE OUTPUT VOLTAGE OF THE DOWNSTREAM HO2S IS LESS THAN SOME CALIBRATABLE FUNCTIONAL WINDOW. KOER DTCS P1137, P1138, P1157 AND P1158 CAN ONLY BE RETRIEVED DURING KOER SELF-TEST WHEN THE FUEL CONTROL IS RAMPED RICH AND LEAN AND MONITORED FOR A VOLTAGE CHANGE ON THE DOWNSTREAM HO2S.
• DTC P0136, P1137 and P1138=HO2S-12
• DTC P0156, P1157 and P1158=HO2S-22
Possible causes:
• Wiring Concerns:
• Pinched, shorted, and corroded wiring and pins
• Crossed sensor wires
• Other Concerns:
• Exhaust leaks
• Contaminated or damaged sensor
Are any of the above concerns present?
|Yes |No |
|SERVICE as necessary. COMPLETE PCM Reset to clear DTCs. RERUN Quick Test. |Continuous Memory DTCs P0136 and P0156: |
| |GO to H81. |
| |All others: |
| |GO to H82. |
H81 CHECK FOR KOER DTCS P1137, P1138, P1157 AND P1158
• KEY OFF.
• Scan Tool connected.
• Key on.
• Engine at 2000 rpm for 3 minutes.
• Activate KOER Self-Test.
• Check for DTCs.
Are DTCs P1137, P1138, P1157 or P1158 present?
|Yes |No |
|GO to H82. |For DTCs P0136 and P0156: |
| |The fault that produced the DTC is intermittent. GO to Pinpoint Test Step Z1 with the following data: HO2S-12,22 |
| |PIDs and list of Possible causes. |
H82 CHECK EXHAUST SYSTEM FOR LEAKS
NOTE: ANY EXHAUST LEAKS BETWEEN THE ENGINE AND THE END OF THE CATALYST CAN CAUSE DTCS P0136 AND P0156.
• Key off.
• Place vehicle on a hoist, transmission in PARK, emergency brake applied, raise vehicle.
• Inspect the following:
• Exhaust flanges for leaks.
• HO2S torque.
• Check for punctures and cracks in catalyst and pipes leading to them.
Are there any exhaust leaks?
|Yes |No |
|REPLACE or SERVICE as required. COMPLETE PCM Reset to clear DTCs. RERUN Quick Test. |GO to H83. |
H83 CHECK HO2S HARNESS CIRCUIT FOR SHORT TO VPWR AND GROUND
• KEY OFF.
• Disconnect Scan Tool from DLC.
• Disconnect PCM. Inspect both ends of connector for damaged or pushed out pins, moisture, corrosion and loose pins. Service as necessary.
• Install breakout box. Leave PCM disconnected.
• Suspect HO2S disconnected.
• Measure the resistance between HO2S Signal Test Pin and SIG RTN Test Pin at the breakout box.
• Measure the resistance between HO2S Signal Test Pin and VPWR and VREF Test Pin at the breakout box.
• Measure the resistance between HO2S Signal Test Pin and PWR GND Test Pin at the breakout box.
• HO2S-12 SIG = Test Pin 35
•
• HO2S-22 SIG = Test Pin 61
• HO2S SIG RTN = Test Pin 91
• PWR GND = Test Pins 24 and 103
• VPWR = Test Pins 71 and 97
• VREF = Test Pin 90
Is resistance greater than 10,000 ohms?
|Yes |No |
|GO to H84. |SERVICE short in harness. REMOVE breakout box. RECONNECT PCM. RERUN Quick Test. |
H84 CHECK RESISTANCE OF HO2S AND HO2S GROUND CIRCUITS
• KEY OFF.
• Breakout box installed, PCM disconnected.
• Suspect HO2S disconnect from harness.
• Measure the resistance between HO2S Signal Test Pin at the breakout box and the HO2S vehicle harness connector. Record readings.
• Measure resistance between SIG RTN Test Pin at the breakout box and HO2S SIG RTN vehicle harness connector. Record readings.
• HO2S-12 SIG = Test Pin 35
• HO2S-22 SIG = Test Pin 61
• HO2S SIG RTN = Test Pin 91
Is the resistance reading less than 5.0 ohms?
|Yes |No |
|GO to H85. |SERVICE open circuit in harness. REMOVE breakout box. RECONNECT all components. RERUN Quick Test. |
H85 CHECK HO2S CIRCUIT RESISTANCE
• KEY OFF.
• PCM connected to vehicle harness.
• Suspect HO2S connected to vehicle harness.
• Scan Tool connected.
• Key on, engine off.
Note: HO2S displayed as O2S on Scan Tool.
• Access the correct HO2S PID.
P0136, P1137 and P1138HO2S-1235 and 91
Is the voltage greater than 1.5 volts?
|Yes |No |
|GO to H88. |GO to H86. |
H86 CHECK RESISTANCE OF HO2S GROUND CIRCUIT IN THE PCM
• KEY OFF.
• PCM connected to breakout box. Vehicle harness disconnected from breakout box.
• Measure the resistance between SIG RTN Test Pin and PWR GND Test Pin at the breakout box.
Is the resistance reading less than 5.0 ohms?
|Yes |No |
|REMOVE breakout box. RECONNECT PCM. GO to H87. |REPLACE PCM. REMOVE breakout box. RECONNECT all components. |
H87 APPLY 12 VOLTS TO SUSPECT HO2S CIRCUIT
• KEY OFF.
• Suspect HO2S disconnected.
• Jumper VPWR to HO2S signal circuit at the vehicle harness connector.
• Key on.
• Access HO2S PID and monitor.
Is the PID value greater than 1.5 volts?
|Yes |No |
|REPLACE HO2S. RECONNECT all components. COMPLETE an HO2S Monitor|REPLACE PCM. RECONNECT all components. COMPLETE an HO2S Monitor |
|Repair Verification Drive Cycle (REFER to Section 2A, Drive |Repair Verification Drive Cycle (REFER to Section 2A, Drive |
|Cycles). RERUN Quick Test. |Cycles). RERUN Quick Test. |
H88 CHECK FOR OVER VOLTAGE ON THE HO2S CIRCUIT IN THE PCM
• KEY ON.
• PCM connected to vehicle harness.
• HO2S disconnected.
• Inspect both ends of connector for damaged or pushed out pins, moisture, corrosion and loose pins. Service as necessary.
• Measure the voltage between SIG RTN Test Pin at the HO2S vehicle harness connector and battery negative post.
• Measure the voltage between HO2S SIG Test Pin at the HO2S vehicle harness connector and battery negative post.
Are the voltage readings greater than 1.5 volts?
|Yes |No |
|REPLACE PCM. RECONNECT all components. RERUN Quick Test. |REPLACE HO2S. RECONNECT all components. RERUN Quick Test. |
H100 KOER P1127
DTC P1127 INDICATES THE HO2S HEATER(S) WERE NOT ON DURING KOER SELF-TEST AND TESTING OF THE HO2S DID NOT OCCUR. THE HO2S HEATERS ARE TURNED ON AND OFF WHEN CERTAIN TEMPERATURES ARE REACHED. THE HO2S HEATERS ARE ACTIVATED BASED ON EXHAUST TEMPERATURE MODELING, WHICH ALLOWS UPSTREAM HEATERS TO BE ENERGIZED INDEPENDENTLY OF THE DOWNSTREAM HEATERS.POSSIBLE CAUSES:
• Engine not operating long enough prior to performing KOER Selt-Test.
• Exhaust system too cool.
• Key off.
• Scan tool connected.
• Key on, engine on.
• Access all HO2S heaters and HO2S heater monitor PIDs.
Do all PIDs indicate ON?
|Yes |No |
|Engine still running. PERFORM KOER Selt-Test. |RUN the engine until all PIDs indicate on. PERFORM KOER Self-Test. |
H110 KOER DTCS P1128 AND P1129
DTC P1128 AND P1129 INDICATE THAT DURING KOER TESTING EITHER THE UPSTREAM OR DOWNSTREAM OR BOTH HO2S SIGNAL(S) ARE SWAPPED FROM BANK TO BANK.
• P1128 refer to the upstream HO2S.
• P1129 refer to the downstream HO2S.
Possible causes:
• Crossed HO2S harness connectors.
• Crossed wiring at HO2S harness connectors.
• Crossed HO2S wiring at 104-pin PCM harness connector.
• Key off.
• Visually inspect vehicle HO2S harness connector(s) for any indication of being crossed (stretched wires, wire harnesses not mounted properly).
Are there crossed connections or wires?
|Yes |No |
|SERVICE as necessary. RERUN Quick Test. |GO to H111. |
H111 VERIFY PROPER HO2S SIGNAL PIN LOCATION
• KEY OFF.
• PCM disconnected, breakout box installed.
• Disconnect both of the suspect HO2S sensors for the vehicle harness connector.
• P1128 = HO2S 11/21 Upstream
• P1129 = HO2S 12/22 Downstream
• Use the DTC and the chart to measure the resistance between the breakout box and the HO2S harness vehicle connectors:
• HO2S-11=Test Pin 60
• HO2S-21=Test Pin 87
• HO2S-12=Test Pin 35
• HO2S-22=Test Pin 61
Is the resistance less than 5.0 ohms?
|Yes |No |
|HO2S SIG circuit is OK. REMOVE breakout box. RECONNECT |CONNECT HO2S connector to proper HO2S signal pins in the PCM 104-pin |
|PCM. RERUN Quick Test. |harness connector or HO2S harness connectors. RERUN Quick Test. |
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