ECM Power and Ground Circuit Check
ECM Power and Ground Circuit CheckWiring Diagram:
Circuit Description
When the ignition switch is turned to ON position, the main relay turns ON (the contact point closes) and the main power is supplied to ECM. And then ECM supplies 5 V power to each sensor (A/C refrigerant pressure sensor, CKP sensor, CMP sensor, APP sensor and TP sensor).
Troubleshooting
NOTE:
- Before troubleshooting, perform following items.
- Be sure to read the Precautions of ECM Circuit Inspection. Precautions For ECM Circuit Inspection
- When measuring circuit voltage and/or pulse signal at ECM connector, connect the special tool to ECM and/or the ECM connectors.
- Confirm that battery voltage is 12 V or more.
- Be sure to check related fuses of ECM power circuit for blown out.
If fuse is blown out, replace fuse(s) and check circuits connected to blown fuse(s) for short circuit to ground.
1. Check ECM power supply circuit as follows.
a. Disconnect ECM connectors from ECM with ignition switch turned OFF.
b. Check each terminal of ECM connectors for proper connection.
c. Measure voltage between each terminal of ECM connector and body ground in the following table. If each measured voltage is out of specified voltage, repair or replace related part.
d. Connect ECM connectors with ignition switch turned OFF.
e. Measure voltage between each terminal of ECM connector and body ground in the following table. If each measured voltage is out of specified voltage, repair or replace related part.
2. Check ECM ground circuit in the following table.
If each measured voltage is out of specified voltage, repair or replace related part.
3. Connect ECM connectors with ignition switch OFF.
4. Check each sensor power supply circuit in the following table.
- If measured voltage is within specified voltage, ECM power and ground circuits is in good condition.
- If each measured voltage is out of specified voltage, repair or replace related part in the following table.
