DTC P0685 ECM/Pcm Power Relay Control Circuit/Open: Notes
DTC detecting condition:
Detected when two consecutive driving cycles with fault occur.
CAUTION:
- After servicing or replacing faulty parts, perform Clear Memory Ref. to ENGINE (DIAGNOSTICS) (H4DOTC)>Clear Memory Mode . and Inspection Mode Ref. to ENGINE (DIAGNOSTICS) (H4DOTC)>Inspection Mode .
- Use the check board when measuring the ECM terminal voltage and resistance.
Wiring diagram:
Engine Electrical System Ref. to WIRING SYSTEM>Engine Electrical System>WIRING DIAGRAM .
DTC detecting condition:
Detected when two consecutive driving cycles with fault occur.
CAUTION:
- After servicing or replacing faulty parts, perform Clear Memory Ref. to ENGINE (DIAGNOSTICS) (H4DOTC)>Clear Memory Mode . and Inspection Mode Ref. to ENGINE (DIAGNOSTICS) (H4DOTC)>Inspection Mode .
- Use the check board when measuring the ECM terminal voltage and resistance.
Wiring diagram:
Engine Electrical System Ref. to WIRING SYSTEM>Engine Electrical System>WIRING DIAGRAM .
- CHECK ECM CONNECTOR.
Check the connecting condition of ECM connector.
Is the ECM connector correctly connected?
- Yes: Go to 2.
- No: Connect the ECM connector correctly.
- CHECK HARNESS BETWEEN ECM AND MAIN RELAY CONNECTOR.
- Turn the ignition switch to OFF.
- Remove the main relay.
- Disconnect the connector from ECM.
- Measure the resistance between the ECM connector and engine ground.
Connector & terminal
(B134) No. 38 - Engine ground:
Is the resistance 1 MΩ or more?
- Yes: Go to 3.
- No: Repair the short circuit to ground in harness between ECM connector and main relay connector.
- CHECK HARNESS BETWEEN ECM AND MAIN RELAY CONNECTOR.
- Install the main relay.
- Turn the ignition switch to ON.
- Measure the voltage between ECM connector and engine ground.
Connector & terminal
(B134) No. 12 (+) - Engine ground (-):
(B134) No. 24 (+) - Engine ground (-):
Is the voltage 10 V or more?
- Yes: repair the harness and connector.NOTE: In this case, repair the following item:
- Short circuit to power supply in harness between ECM connector and main relay connector
- Defective main relay
- No: Repair the poor contact of ECM connector.