Inspection of ECM and Its Circuits - Part 1

Inspection of ECM and Its Circuits - Part 1

ECM 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 coupler disconnected from it.

Voltage Check

1) Remove ECM (1) from vehicle body referring to Service and Repair Engine Control Module (ECM) Removal and Installation.
2) Check voltage at each terminal of couplers (2) 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.
- Pulse signal cannot be measured by voltmeter. It can be measured by oscilloscope.





Viewed from harness side

































1. Reference waveform No. 1

Throttle opening signal at throttle fully closed











2. Reference waveform No. 2

Throttle opening signal at throttle fully opened











3. Reference waveform No. 3

Ignition pulse (Engine revolution) signal (2) at engine idling
















4. Reference waveform No. 4

Ignition pulse (Engine revolution) signal (2) at engine idling
















5. Reference waveform No. 5

Engine coolant temp signal at engine idling
















6. Reference waveform No. 6

Engine coolant temp signal at engine idling
















7. Reference waveform No. 7

Engine torque reduction signal (1) from TCM











8. Reference waveform No. 8

Engine torque reduction signal from TCM











9. Reference waveform No. 9

VSS signal (1) at 20 km/h (13 mil/h)
















10. Reference waveform No. 10

VSS signal (1) at 20 km/h (13 mil/h)
















11. Reference waveform No. 11

Serial data line for TCM
















12. Reference waveform No. 12

No.3 Fuel injector signal at engine idling
















13. Reference waveform No. 13

Fuel injector signal (1) at engine idling











14. Reference waveform No. 14

No.4 Fuel injector signal (2) at engine idling
















15. Reference waveform No. 15

EGR valve No.1 coil (2) and No.2 coil (1) signal











16. Reference waveform No. 16

Heated oxygen sensor signal at engine idling
















Continued in Part 2