Engine General Information and Diagnosis 1

Inspection of ECM and Its Circuits

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

Viewed from harness side:

1. Remove ECM (1) from vehicle body.
2. Check voltage and/or pulse signal at each terminal of couplers (2) connected using voltmeter (3) and oscilloscope (4).

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 (*) cannot be measured by voltmeter because it is pulse signal. Check it with oscilloscope if necessary.

Ter. G04-1 - G04-15:

Ter. G04-16 - G04-27:

Ter. G04-28 - G04-35:

Ter. G45-1 - G45-3:

Ter. G45-4 - G45-23:

Ter. G45-24 - G45-35:

Ter. G46-1 - G46-2:

Ter. G46-3 - G46-15:

Ter. G46-16 - G46-25:

Ter. G46-26 - G46-31:

Terminal arrangement of ECM (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