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DTC

P0500 - Vehicle Speed Sensor (VSS) Malfunction  

Description

Indicates the powertrain control module (PCM) detected an error in the vehicle speed information. Vehicle speed data is received from either the vehicle speed sensor (VSS), transfer case speed sensor (TCSS), anti-lock brake system (ABS) control module, generic electronic module (GEM), or central timer module (CTM). If the engine rpm is above the torque converter stall speed (automatic transmission) and engine load is high, it can be inferred that the vehicle must be moving. If there is insufficient vehicle speed data input, a malfunction is indicated and a DTC is set. On most vehicle applications the malfunction indicator lamp (MIL) will be triggered when this DTC is set.

Possible Causes

• Open in VSS+/VSS- harness circuit.

• Open in TCSS signal or TCSS signal return harness circuit.

• Short to GND in VSS harness circuit.

• Short to GND in TCSS harness circuit.

• Short to PWR in VSS harness circuit.

• Short to PWR in TCSS harness circuit.

• Open or short in the vehicle speed circuit(s) (VSC) between the PCM and appropriate control module.

• Damaged VSS or TCSS.

• Damaged wheel speed sensors.

• Damaged wheel speed sensor harness circuits.

• Damage in module(s) connected to VSC/VSS circuit.

• Damage drive mechanism for VSS or TCSS.

Diagnostic Aides

Diagnostic Aids: - Monitor VSS PID while driving vehicle. This DTC is set when the PCM detects a sudden loss of VSS signal over a period of time. If vehicle speed data is lost, check source of where vehicle speed signal originates. Note TCSS does not have a PID, circuitry frequency must be checked for sudden loss of sensor signal.

|Trouble Code: P0500 (6.8L V10 VIN S Auto) |Print this code data[pic] |

|Vehicle Speed Sensor Malfunction | |

Number of Trips to Set Code:   2

• CCM Details

• MIL Details

Trouble Code Conditions:

Engine running, then with the engine speed more than the TCC stall speed, the PCM detected a lack of vehicle speed data occurred. Note: The PCM receives vehicle speed data from the VSS, TCSS, ABS module, CTM or GEM controller, depending up the application.

Possible Causes: 

• Modules connected to VSC/VSS harness circuits are damaged

• Mechanical drive mechanism for the VSS or TCSS is damaged

• VSS+ or VSS- harness circuit is open

• TCSS signal or TCSS signal return harness circuit is open

• VSS harness circuit, TCSS harness circuit is shorted to ground

• VSS harness circuit, CSS harness circuit is shorted to power

• VSS circuit open between the PCM and related control module

• VSS or TCSS, or wheel speed sensors circuits are damaged

• TSB 01-21-13 contains a repair procedure for this trouble code

Top of Form

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|[pic]PATH:  Diagnostics > Diagnostic Routines > Powertrain > On Board Diagnostics II > Pinpoint Tests > DP: Vehicle Speed | |

|Sensor (VSS)/Transfer Case Speed Sensor (TCSS) | |

DP: Vehicle Speed Sensor (VSS)/Transfer Case Speed Sensor (TCSS)

|2000 PCED On Board Diagnostics II |SECTION 5: Pinpoint Tests |

|  |  |

|  |Procedure revision date: 01/31/2001 |

| |  |

|DP: Vehicle Speed Sensor (VSS)/Transfer Case Speed Sensor (TCSS) |← DP: Introduction |

|  | |

DP1 DTC P0500/P0501/P1502: CHECK VSS CIRCUITS FOR OPEN IN HARNESS (VRS TYPE)

NOTE: REFER TO THE PCM CONNECTOR PIN NUMBERS IN THE BEGINNING OF THIS PINPOINT TEST.

• Disconnect PCM.

• Disconnect VSS.

• Measure resistance of VSS+ circuit between PCM harness connector pin and VSS+ sensor harness connector.

• Measure resistance of VSS- circuit between PCM harness connector pin and VSS- sensor harness connector.

Is each resistance less than 5.0 ohms?

|Yes |No |

|GO to DP2. |REPAIR open circuit. COMPLETE an OBD II Drive Cycle (REFER to Diagnostic Methods, Drive Cycles). |

DP2 CHECK VSS CIRCUITS FOR SHORT TO GROUND AND POWER IN HARNESS

• MEASURE RESISTANCE BETWEEN VSS+ AND PWR GND CIRCUITS AT PCM HARNESS CONNECTOR.

• Measure resistance between VSS+ and VSS- circuits at PCM harness connector.

• Measure resistance between VSS+ and VPWR circuits at PCM harness connector.

Is each resistance greater than 5.0 ohms?

|Yes |No |

|GO to DP3. |GO to DP12. |

DP3 CHECK VSS RESISTANCE

• MEASURE VSS RESISTANCE.

Is resistance between 170 and 270 ohms?

|Yes |No |

|REPLACE the PCM (refer to Diagnostic Methods, Flash EEPROM). COMPLETE an |REPLACE the VSS. COMPLETE an OBD II Drive Cycle (REFER |

|OBD II Drive Cycle (REFER to Diagnostic Methods, Drive Cycles). |to Diagnostic Methods, Drive Cycles). |

DP5 DTC P0500/P0501/P1502: CHECK VSS SIGNAL OUTPUT TO (PCM) POWERTRAIN CONTROL MODULE (HALL TYPE)

• DISCONNECT PCM.

• Raise the vehicle to allow rotation of the front drive wheel.

• Key on, transmission in NEUTRAL.

Note: The opposite wheel must be held stationary.

• Measure voltage between VSS+ and PWR GND circuits at the PCM harness connector, while slowly rotating the drive wheel.

• The voltage should rise above 5.0 volts and fall below 1.0 volt in a regular cycle. Observe several cycles.

• Key off.

Does the VSS output voltage rise and fall as specified while slowly rotating the drive wheel?

|Yes |No |

|REPLACE PCM (refer to Diagnostic Methods, Flash EEPROM). COMPLETE an OBD II Drive Cycle (REFER to Diagnostic |GO to DP6. |

|Methods, Drive Cycles). | |

DP6 CHECK VOLTAGE BETWEEN VPWR AND PWR GND CIRCUITS AT VSS

• DISCONNECT VSS.

• Key on.

• Measure voltage between VPWR and PWR GND circuits at the VSS harness connector.

Is the voltage greater than 10.5 volts?

|Yes |No |

|GO to DP7. |KEY OFF. GO to DP10. |

DP7 CHECK VSS CIRCUIT FOR SHORT TO POWER IN HARNESS

• KEY ON.

• Measure voltage between VSS+ and PWR GND circuits at the PCM harness connector.

• Key off.

Is voltage less than 1.0 volt?

|Yes |No |

|GO to DP8. |GO to DP12. |

DP8 CHECK VSS CIRCUIT FOR SHORT TO GROUND IN HARNESS

• MEASURE RESISTANCE BETWEEN VSS+ AND PWR GND CIRCUITS AT THE PCM HARNESS CONNECTOR.

Is resistance greater than 3,000 ohms?

|Yes |No |

|GO to DP9. |GO to DP12. |

DP9 CHECK VSS SIGNAL CIRCUIT FOR OPEN IN HARNESS

• MEASURE RESISTANCE OF VSS+ SIGNAL CIRCUIT BETWEEN PCM HARNESS CONNECTOR PIN AND VSS+ SENSOR HARNESS CONNECTOR.

Is resistance less than 5.0 ohms?

|Yes |No |

|REPLACE VSS. COMPLETE an OBD II Drive Cycle (REFER to |REPAIR open circuit. COMPLETE an OBD II Drive Cycle (REFER to |

|Diagnostic Methods, Drive Cycles). |Diagnostic Methods, Drive Cycles). |

DP10 CHECK VSS GROUND CIRCUIT FOR OPEN IN HARNESS

• MEASURE RESISTANCE OF PWR GND CIRCUIT BETWEEN VSS HARNESS CONNECTOR AND CHASSIS GROUND.

Is resistance less than 5.0 ohms?

|Yes |No |

|REPAIR open VPWR to VSS. COMPLETE an OBD II Drive Cycle (REFER|REPAIR open VSS PWR GND circuit. COMPLETE an OBD II Drive Cycle |

|to Diagnostic Methods, Drive Cycles). |(REFER to Diagnostic Methods, Drive Cycles). |

DP12 VERIFY IF VSS CIRCUIT IS SHORTED IN HARNESS OR ANOTHER MODULE

• DETERMINE WHICH, IF ANY, MODULES ARE CONNECTED TO THE VSS CIRCUIT (REFER TO WIRING DIAGRAMS MANUAL). IF NO OTHER MODULES ARE CONNECTED TO THE VSS CIRCUIT, GO TO THE "YES" ACTION TO TAKE.

• One at a time, disconnect the modules associated with the VSS circuit. After disconnecting each module, again test for short circuit (Refer to test step that sent you here). Repeat until each associated module has been disconnected or the short circuit has been eliminated.

Does the short circuit remain after all associated modules were disconnected?

|Yes |No |

|REPAIR short circuit. COMPLETE an OBD II Drive Cycle (REFER to Diagnostic |REFER to the Workshop Manual for further diagnosis of |

|Methods, Drive Cycles). |appropriate module. |

DP15 KOER DTC P1501: CHECK PCM VSS PID FOR INPUT SIGNAL

• START THE ENGINE AND IDLE IN NEUTRAL.

• Access the VSS PID with a scan tool and observe for vehicle speed input to the PCM.

• Increase the engine speed, not greater than 2000 rpm, several times while observing the VSS PID.

Is the reading on the VSS PID less than 5 km/h (3 mph)?

|Yes |No |

|Unable to duplicate or identify fault at this time. If DTC P1501 still exists. GO to Z1. (REFER to Diagnostic |GO to DP22. |

|Subroutines, Diagnostic Trouble Code [DTC] Descriptions for a list of possible causes.) | |

DP20 DTC P0503: INSPECT VSS AND CIRCUIT FOR AN INTERMITTENT

• CHECK FOR HARNESS INTERMITTENTS BY VERIFYING THAT PINS ARE PROPERLY SEATED IN CONNECTOR SHELL, WIRING IS PROPERLY CRIMPED, NO CORROSION EXISTS IN THE HARNESS AND SENSOR IS SECURELY MOUNTED.

Are there any indications of harness intermittents?

|Yes |No |

|REPAIR as necessary. COMPLETE an OBDII Drive Cycle (REFER to Diagnostic Methods, Drive Cycles). |GO to DP21. |

DP21 CHECK PCM VSS PID FOR INPUT SIGNAL

• ACCESS THE VSS PID WITH A SCAN TOOL.

• Drive the vehicle at several steady state speeds above and below 50 km/h (30 mph).

Note: For Scan Tools which have Data Record feature, record data for playback to help identify variations.

• During each steady state speed observe the VSS PID for variations of (+) or (-) 8 km/h (5 mph) for greater than 10 seconds.

Is there any indications of a noisy or intermittent signal with the VSS PID?

|Yes |No |

|GO to DP22. |Unable to duplicate or identify fault at this time. REPAIR any other DTCs. |

DP22 CHECK VSS HARNESS ROUTING

• CHECK VSS HARNESS ROUTING:

• Verify that the harness is not routed adjacent to high current wires such as ignition wires or generator wiring.

• Verify VSS harness is shielded and grounded, if applicable.

• Check resistance of the VSS harness; refer to Pinpoint Test Schematic and Connectors at beginning of pinpoint test.

Are any concerns evident?

|Yes |No |

|REPAIR as necessary. COMPLETE an OBDII Drive Cycle |Unable to duplicate or identify a fault at this time. GO to Z1. (REFER to |

|(REFER to Diagnostic Methods, Drive Cycles). |Diagnostic Subroutines, Diagnostic Trouble Code [DTC] Descriptions for a |

| |list of possible causes.) |

DP25 DTC P1500: VISUAL INSPECTION

• VISUALLY INSPECT THE VSS AND VSS HARNESS CIRCUITS FOR ANY POTENTIAL FAILURES. USE THE FOLLOWING CHECK LIST FOR REFERENCE:

• Loose VSS connector.

• Pushed out VSS connector pins.

• Damaged VSS wiring harness insulation.

• Incorrect harness routing.

• Incorrect VSS mounting.

Did the visual inspection reveal a potential failure?

|Yes |No |

|REPAIR fault as necessary. COMPLETE an OBD II Drive |RESTORE vehicle. Unable to duplicate or identify fault at this time. GO to |

|Cycle (REFER to Diagnostic Methods, Drive Cycles). |Z1. (REFER to Diagnostic Subroutines, Diagnostic Trouble Code [DTC) |

| |Descriptions for a list of possible causes.) |

DP30 DTC P0500, P1502 VISUAL INSPECTION

NOTE: THE TRANSFER CASE SPEED SENSOR (TCSS) PROVIDES ROTATIONAL SPEED OF OUTPUT SHAFT OF THE TRANSFER CASE. THE PCM USE THIS INFORMATION TO CONTROL POWERTRAIN BEHAVIOR AND ON SOME APPLICATIONS IS USED AS THE SOURCE OF VEHICLE SPEED INFORMATION.

• Disconnect TCSS sensor.

• Inspect TCSS vehicle harness connector for damage and proper seating.

Have any problems been found?

|Yes |No |

|REPAIR as necessary. |GO to DP31. |

DP31 CHECK RESISTANCE OF TCSS SENSOR

• MEASURE RESISTANCE BETWEEN TCSS SIGNAL AND TCSS SIGTRN CIRCUITS AT THE TCSS SENSOR.

Is resistance between 1,000 and 1,250 ohms?

|Yes |No |

|GO to DP32. |REPLACE TCSS sensor. |

DP32 TCSS OUTPUT CHECK

• MEASURE FREQUENCY BETWEEN TCSS SIGNAL AND TCSS SIGRTN CIRCUITS AT THE TCSS SENSOR.

• Drive vehicle between 0 and 48 km/h (0 and 30 mph).

• Refer to Reference Values, Reference Values for frequency ranges.

Does frequency reading increase and decrease with vehicle speed?

|Yes |No |

|GO to DP33. |REMOVE the TCSS and inspect target wheel. REPAIR as necessary. IF OK REPLACE TCSS. |

DP33 CHECK HARNESS FOR SHORT TO PWR

• KEY ON.

• TCSS sensor disconnected.

• Measure voltage between the TCSS signal circuit at the TCSS harness connector and ground.

If voltage less than 1.0 volt?

|Yes |No |

|KEY OFF. GO to DP34. |REPAIR short circuit. |

DP34 CHECK HARNESS FOR OPEN

• DISCONNECT PCM.

• Measure resistance of TCSS signal circuit between PCM harness connector pin and TCSS sensor harness connector.

• Measure resistance of TCSS SIGRTN circuit between PCM harness connector pin and TCSS sensor harness connector.

Is each resistance less than 5.0 ohms?

|Yes |No |

|GO to DP35. |REPAIR open circuit. |

DP35 CHECK HARNESS FOR SHORT TO GROUND

• MEASURE RESISTANCE BETWEEN TCSS SIGNAL AND SIGRTN CIRCUITS AT THE TCSS HARNESS CONNECTOR.

• Measure resistance between TCSS signal and GND circuits at the TCSS harness connector.

Is each resistance greater than 10,000 ohms?

|Yes |No |

|REPLACE PCM (refer to Diagnostic Methods, Flash EEPROM). |REPAIR short circuit. |

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