W/Harness Inspection
Engine Control
P0685 PCM/PCM Power Relay Control Circuit /Open - Inspection/Repair:_:W/Harness Inspection
Terminal and Connector Inspection
1. Many malfunctions in the electrical system are caused by poor harness and terminals. Faults can also be caused by interference from other electrical systems, and mechanical or chemical damage.
2. Thoroughly check connectors for looseness, poor connection, bending, corrosion, contamination, deterioration, or damage.
3. Has a problem been found?
YES
> Repair as necessary and go to "Verification of Vehicle Repair" procedure
NO
> Go to " Power Circuit Inspection " procedure.
Power Supply Circuit Inspection
Check voltage
1. IG "OFF"
2. Disconnect the main relay.
3. IG "ON" and ENG "OFF"
4. Measure the voltage between power supply terminals of main relay harness connector and chassis ground.
A. Specification : B+
5. Is the measured voltage within specification ?
YES
> Go to "Control Circuit Inspecition" procedure.
NO
> Check fuse between battery and main relay is disconnected.
> Repair or replace open or short in harness and then go to "Verification of Vehicle Repair" procedure.
Control Circuit Inspection
Check short in harness
1. IG "OFF".
2. Disconnect main relay and PCM connector.
3. Measure the resistance between control terminal of main relay harness connector and chasses ground.
A. Specification : Infinite
4. Is the measured resistance within specification ?
YES
1) Go to "Check open in harness" as follows.
NO
1) Repair or replace as necessary and then go to " Verification of Vehicle Repair" procedure.
Check open in harness
1. IG "OFF".
2. Disconnect main relay and PCM connector.
3. Measure the resistance between control terminal of main relay harness connector and main relay control terminal of PCM harness connector.
A. Specification : Approx. below 1Ohms
4. Is the measured resistance within specifications ?
YES
1) Go to "Component Inspection" procedure.
NO
1) Repair or replace as necessary and then, go to "Verification of Vehicle Repair" procedure.