Systems Repair Worksheet - Grafton School District



Systems Repair Worksheet Chapter 22 Pages 670-703 Name      

Electronics & Computer Systems 95 Points Due Date      

1. Electronics is the technology of electricity and all of the basic laws of

electricity also apply to all electronic controls. (Ohm’s Law!) (opens, shorts, high resistances)

2. A is used to quickly store (charge) & release (discharge) electrical energy.

3. The ability of a capacitor to store energy is called and the standard of measure

for capacitance is the farad (F). A 1 farad capacitor can store 1 coulomb of charge at 1 volt.

4. Capacitors oppose a change in and are used as noise reduction units in circuits.

5. Ultra-capacitors or super-capacitors are used in vehicles to store & release energy.

6. are materials with exactly 4 electrons in their “valence rings”.

They can function as either conductors or as insulators and are used to build solid state devices.

7. Common semiconductor materials are (Si) and (Ge).

8. Semi-conductors carry current without losing electrons through the concept of .

The holes in a P-type material, being positively charged, attract electrons causing movement.

9. The is the simplest semiconductor device. It is a one-way valve for electron flow.

10. The diode contains a junction. A diode conducting is said to be biased

and will typically have a voltage drop of .4 to .7 volts. (Silicon or Germanium)

11. A diode that is blocking or not allowing flow is said to be biased and reads OL

when checked with the diode test mode of a DMM. (think of bias as meaning “condition”)

12. Diodes “turn on” (conduct) when the (direction) of the current flow is correct

and “turn off” (block flow) or (OL) when the polarity is incorrect. anode (+) & cathode (-)

13. Diodes are popular in systems where they are used to rectify AC to DC.

14. diodes allow reverse polarity flow with out damage after their “threshold or zener

voltage” is reached. They are used often in charging system voltage regulators. (14.2 zener voltage)

15. diodes are connected in parallel across coils of wire to prevent damage from

induced voltage spikes returning to the PCM and other electronic components as the coils shut off.

16. When a (LED) is forward biased, it lights up and has a

higher voltage drop than a regular silicon diode.

17. A is a semiconductor switch “controlled by conditions”. It switches a circuit

on or off from the signal of another circuit. Transistors can be thought of as solid state relays.

18. A transistor is like two diodes assembled back-to-back to form either a or an type.

19. The names of the 3 legs of a transistor are: E) B) C)

20. A voltage (ground) must be applied to the base of a PNP transistor to turn it on.

21. A voltage (hot) must be applied to the base of an NPN transistor to turn it on.

Transistors operate with a forward bias voltage drop and current gain factor. (ask the teacher)

22. An (IC or chip) is a large # of diodes, transistors, resistors,

capacitors, mounted to a semiconductor material used to make logic decisions & commands.

23. A (ECM or module) is an electronic device that stores & processes data.

24. A is a small version of a computer. (PCM or any ECU/CPU)

25. 1) 2) 3) 4) are the four basic

functions or operations of a computer. (Sensors > PROM > RAM > Actuators)

26. The PCM (CPU) receives sensor input signals that it checks against values.

27. are used as inputs for operations that only require a yes-no or an on-off condition.

28. means that the data concerning the effects of the PCM’s output commands are

fed back to the computer as an input signal. A good example of this is the HO2S or Relay 87a signal.

29. All perform the same basic function. They a mechanical condition,

(movement or position) a chemical state, or a temperature condition and change it (transducer)

into an electrical signal that can be used by the computer to make decisions.

30. All sensors fall under one of two operating categories:

voltage sensors or variable resistance sensors (also known as passive sensors)

passive devices like thermistors (IAT & ECT), piezoresistive (MAP), potentiometers (TPS), & A/F

Voltage sensors (also known as active sensors)

active devices like magnetic pulse generators (VSS & CKP), Hall-effect switches (RPM),

Zirconium Dioxide (HO2S), piezoelectric (KS)

31. Voltage does not flow through a conductor, flows while voltage pushes it.

32. Voltage is used as a signal by changing its , ,or switching polarity.

33. voltage signals are infinitely variable. Like an ECT which varies within a given range.

34. voltage signals are in one of either 3 states: on-off, yes-no, or high-low.

This is like a Hall-effect or PNP switch square-waved pattern because of the abrupt changes in the signal

35. Since computers can only read digital signals, analog signals must go though an

analog/digital (A/D) converter in order to be used or properly “understood” by the computer.

36. A computer has a crystal oscillator or that vibrates at a fixed rate and delivers a

constant time pulse. The clock maintains an orderly flow of timed information in the computer.

37. Communication rate, expressed in bits per second processed, is called .

38. Permanent information is stored in the . (ROM)

39. are sets of instructions in the ROM for every possible

condition the computer may detect.

40. Temporary information (DTC’s) is stored in . (RAM)

41. KAM = NVRAM = RAM

42. PROM = ROM EPROM = PROM EEPROM = EPROM

43. (outputs) may be solenoids, switches, relays, or motors controlled by the PCM

and turned on & off by an output driver, which is a transistor on the ground side of an actuator.

44. measures a percentage of circuit on-time. it the

measurement of the exact amount of time something is turned on, expressed in milliseconds.

45. The PCM has volt input, but the reference voltage for sensors is often dropped to volts.

46. Control modules function in awake mode, but may enter a mode to save power.

47. OBD-II offers a standardized in a specific location and a standard list of .

48. “ technology” eliminates the mechanical connection from inputs to the PCM and from

the PCM to outputs. Examples are drive-by-wire, shift-by-wire, brake-by-wire, etc.

49. , also called “in-vehicle networking” provides efficient communications

between modules in various vehicle systems.

50. A multiplex wiring system uses a that connects different computers

or control modules together. Sharing data saves money on redundant sensors & wiring.

51. Data is sent in digital binary code with each individual signal preceded by an

code that establishes its priority. Each module processes only one input signal at a time.

52. rates on the network are between 10,000 and 1, 000,000 bits per second.

53. The serial data bus is typically 2 wires, a ground and a transmission wire in a pair.

54. A is the name for the language that computers speak when they are conversing.

55. Class A is speed CAN for convenience systems and use a generic UART. (U DTC’s)

UART = Universal Asynchronous Receiver/Transmitter USB = Universal Serial Bus

56. Class B is speed CAN for instrument cluster & emissions data recording.

57. Class C is speed CAN for real-time control of the powertrain and vehicle dynamics.

58. The total network in most vehicles is composed of 2 or 3 . LS, MS, & HS CAN

59. The networks are integrated & translated through the use of a module. (BCM)

60. Each twisted wire in the CAN bus carries a different .

61. To eliminate voltage spikes and CAN system noise, two ohm resistors are connected in

parallel across the ends of the main CAN bus wires. These are called “Terminating Resistors”.

62. Electrical & electronic vehicle systems must be properly handled & protected by the technician to

prevent causing more problems than the vehicle came into the shop with!

Avoid starting if at all possible. Remove the jumper cables before operating electrical devices.

Do not connect or disconnect electrical components with the ignition switched on.

Avoid touching bare metal contacts since oils can cause corrosion & poor electrical contact.

Do not expose electronic circuits to electricity. This can generate more than 25,000 volts!

Do not short sensors with a unless told to do so in manufacturers service publications.

Never apply 12 to electronic components & never use a 12-volt to test electronics.

Sensor wiring should never be ! Inductive voltages from other devices can send false signals.

Incorrect testing procedures can cause circuits which will instantly destroy modules.

Remove any module that could be affected by , hammering, grinding, or metal straightening.

Follow tool sequences for connecting & disconnecting carefully…power down & exit carefully!

The system is critical to proper electronic engine control operation. 15 volts will kill a PCM.

DMM’s used to test electronic circuitry must be -. 10,000,000 internal ohms!

When probing electrical connectors, use -probing to avoid damage done to insulation by wire piercing.

When -probing electrical connectors, do not to force so far into the female side to cause an open.

63. types of DTCs are used by the CAN bus: loss of communication, signal error, & internal error.

64. If bus wire needs to be repaired, it must not be or .

65. Reprogramming of modules with update information is called “” the computer.

66. Resistors, diodes, and capacitors should al be checked using a - DMM.

67. It is best to use a when checking frequency (hertz) of a signal. (cycles per second)

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