Inspection of ECM (PCM) and Its Circuits
Inspection of ECM and Its CircuitsECM and its circuits can be checked at ECM wiring couplers by measuring voltage, pulse signal and resistance.
CAUTION: ECM cannot be checked by itself. It is strictly prohibited to connect voltmeter or ohmmeter to ECM with couplers disconnected from it.
Voltage and signal Check
1. Remove ECM cover from bracket.
2. Using voltmeter (1) or oscilloscope (2), check voltage at each terminal of couplers connected.
NOTE:
- As each terminal voltage is affected by the battery voltage, confirm that it is 11 V or more when ignition switch is turned ON.
- Voltage with asterisk(*) can not be measured by voltmeter because it is pulse signal. Check it with oscilloscope if necessary.
Viewed from Harness Side:
Ter. E61-1 - E61-18:
Ter. E61-18 Cont. - E61-30:
Ter. E61-30 Cont. - E61-35:
Ter. C51-3-1 - C51-3-8:
Ter. C51-3-9 - C51-3-26:
Ter. C51-1-1 - C51-1-16:
Ter. C51-1-16 Cont. - C51-1-28:
Ter. C51-2-1 - C51-2-5:
Ter. C51-2-6 - C51-2-17:
Ter. C51-2-18 - C51-2-26:
Ter. C51-2-27 - C51-2-30:
ECM connector (Viewed from harness side)
1. Reference waveform No. 1
Throttle position signal for cruise control module at throttle fully closed
2. Reference waveform No. 2
Throttle position signal for cruise control module at throttle fully opened
3. Reference waveform No. 3
Engine revolution (ignition pulse) signal (1) at engine idling
4. Reference waveform No. 4
Engine revolution (ignition pulse) signal (1) at engine idling
5. Reference waveform No. 5
Engine coolant temperature signal for combination meter at engine idling
6. Reference waveform No. 6
CAN communication line signal at engine idling
7. Reference waveform No. 7
Knock sensor signal at engine speed 4000 r/min.
8. Reference waveform No. 8
Knock sensor signal at engine speed 4000 r/min.
9. Reference waveform No. 9
Manifold absolute pressure sensor signal (1) at engine racing
10. Reference waveform No. 10
Mass air flow sensor signal (1) at engine racing
11. Reference waveform No. 11
Heated oxygen sensor signal (Bank 1) at engine running
12. Reference waveform No. 12
Heated oxygen sensor signal (Bank 2) at engine running
13. Reference waveform No. 13
IAC valve signal
14. Reference waveform No. 14
CMP sensor signal at engine idling
15. Reference waveform No. 15
CMP sensor signal at engine idling
16. Reference waveform No. 16
VSS signal (1) at 60 km/h (38 mph) for A/T vehicle
17. Reference waveform No. 17
VSS signal (1) at 60 km/h (38 mph) for A/T vehicle
18. Reference waveform No. 18
EVAP canister purge valve signal
19. Reference waveform No. 19
Fuel injector signal at engine idling
20. Reference waveform No. 20
Fuel injector No.2 signal (4) at engine idling
21. Reference waveform No. 21
Fuel injector No.1 signal (4) at engine idling
22. Reference waveform No. 22
Heated oxygen sensor heater signal (Bank 1) at engine idling
23. Reference waveform No. 23
Heated oxygen sensor heater signal (Bank 2) at engine idling
24. Reference waveform No. 24
Intake manifold tuning vacuum solenoid valve signal (1) at engine racing
25. Reference waveform No. 25
Fuel injector No.4 signal (4) at engine idling
26. Reference waveform No. 26
Fuel injector No.3 signal (4) at engine idling
27. Reference waveform No. 27
EGR valve signal at engine racing
28. Reference waveform No. 28
CKP sensor signal (1) at engine idling
29. Reference waveform No. 29
CKP sensor signal at engine idling
30. Reference waveform No. 30
Fuel injector No.6 signal (4) at engine idling
31. Reference waveform No. 31
Fuel injector No.5 signal (4) at engine idling
32. Reference waveform No. 32
Ignition coil signal at engine idling
33. Reference waveform No. 33
Ignition coil No.6 signal (3) at engine idling
34. Reference waveform No. 34
Ignition coil No.5 signal (3) at engine idling
35. Reference waveform No. 35
Ignition coil No.4 signal (3) at engine idling
36. Reference waveform No. 36
Ignition coil No.3 signal (3) at engine idling
37. Reference waveform No. 37
Ignition coil No.2 signal (3) at engine idling
38. Reference waveform No. 38
Ignition coil No.1 signal (3) at engine idling
Resistance Check
1. Disconnect couplers (1) from ECM with ignition switch OFF.
CAUTION: Never touch terminals of ECM itself or connect voltmeter or ohmmeter (2).
2. Check resistance between each pair of terminals of disconnected couplers (1) as listed in the following table.
CAUTION:
- Be sure to connect ohmmeter (2) probe from wire harness side of coupler.
- Be sure to turn OFF ignition switch for this check.
- Resistance in table represents that when parts temperature is 20 °C (68 °F).