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 Mode Ref. to ENGINE (DIAGNOSTICS) (H4DO)>CLEAR MEMORY MODE>OPERATION ., and inspection mode Ref. to ENGINE (DIAGNOSTICS) (H4DO)>INSPECTION MODE>PROCEDURE .
- 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.
- Measure the voltage between ECM connector and engine ground.
Connector & terminal
(B134) No. 1 (+) - Engine ground (-):
(B134) No. 14 (+) - 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: Go to 3 .
- 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. 60 - Engine ground:
Is the resistance 1 MΩ or more?
Yes: Repair the poor contact of ECM connector.
No: Repair the short circuit to ground in harness between ECM connector and main relay connector.