DTC P0685 ECM/Pcm Power Relay Control Circuit/Open: Notes
DTC DETECTING CONDITION:
Detected when two consecutive driving cycles with fault occur.
TROUBLE SYMPTOM:
- Hard to start
- Improper idling
- Poor driving performance
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
.
WIRING DIAGRAM:
- Engine Electrical System NON-TURBO MODEL (WITHOUT PUSH BUTTON START) Ref. to WIRING SYSTEM > Engine Electrical System > NON-TURBO MODEL (WITHOUT PUSH BUTTON START) .
- Engine Electrical System NON-TURBO MODEL (WITH PUSH BUTTON START) Ref. to WIRING SYSTEM > Engine Electrical System > NON-TURBO MODEL (WITH PUSH BUTTON START) .
- 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
(B135) No. 13 - 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
(B136) No. 6 (+) - Engine ground (-):
(B137) No. 1 (+) - 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.