W/Harness Inspection

Engine

Engine Control - P0685 ECM/PCM Power Relay Control Circuit /Open - 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?






Power Circuit Inspection

1. IG "OFF"
2. Disconnect Main Relay
3. IG "ON" & ENG "OFF".
4. Measure voltage between harness terminal 2 of Main Relay and chassis ground.
5. Measure voltage between harness terminal 5 of Main Relay and chassis ground.

Specification : Approx. B+




6. Is the measured voltage within specification?






Control Circuit Inspection

1. Check short in coil control
(1) IG "OFF".
(2) Disconnect Main Relay and PCM connector.
(3) Measure resistance between harness terminal 4 and chassis ground.
(4) Measure resistance between harness terminal 4 and 5 of Main Relay.

Specification : Infinite




(5) Is the measured voltage within specification?





2. Check open in coil control
(1) IG "OFF".
(2) Disconnect Main Relay and PCM connector.
(3) Measure resistance between harness terminal 4 of Main Relay and harness terminal 43 of PCM harness connector.

Specification : Approx. below 1 Ohms




(4) Is the measured resistance within specification?