P0685

COMPONENT LOCATION





GENERAL DESCRIPTION

The ECM provides ground to one side of the coil of the main relay and the other side is connected to the battery. The ECM monitors battery voltage and the voltage after the main relay.

DTC DESCRIPTION

Checking the contolling state of main relay every 10 sec. under detecting condition, if open or short in the circuit is detected for more than 5 sec., PCM sets P0685.

DTC DETECTING CONDITION





SPECIFICATION





SCHEMATIC DIAGRAM





MONITOR DTC STATUS

1. Check DTC Status
(1) Connect scantool to Data Link Connector(DLC).
(2) IG "ON".
(3) Select "Diagnostic Trouble Codes(DTCs)" mode, and then Press F4(DTAL) to check DTC's information from the DTCs menu
(4) Read "DTC Status" parameter.




(5) Is parameter displayed "Present fault"?
YES
> Go to "Terminal and connector inspection" procedure.
NO
> Fault is intermittent caused by poor contact in the sensor's and/or PCM's connector or was repaired and PCM memory was not cleared. Thoroughly check connectors for looseness, poor connection, ending, corrosion, contamination, deterioration, or damage. Repair or replace as necessary and go to "Verification of Vehicle Repair" procedure.

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 CIRCUIT INSEPCTION

1. IG "OFF"
2. Disconnect Main Relay
3. IG "ON" & ENG "OFF".
4. Measure voltage between harness terminal 85 of Main Relay and chassis ground.
5. Measure voltage between harness terminal 30 of Main Relay and chassis ground.

Specification : B+





6. 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

1. Check short in coil control
(1) IG "OFF".
(2) Disconnect Main Relay and PCM connector.
(3) Measure resistance between harness terminal 86 and chassis ground.
(4) Measure resistance between harness terminal 86 and 30 of Main Relay.

Specification : Infinite





(5) Is the measured resistance within specification ?
YES
> Go to "Check open in coil control" as follows.
NO
> Repair or replace as necessary and then go to " Verification of Vehicle Repair" procedure.
2. Check open in coil control
(1) IG "OFF".
(2) Disconnect Main Relay and PCM connector.
(3) Measure resistance between harness terminal 86 of Main Relay and harness terminal C201-1 (43) of PCM harness connector.

Specification : Approx. below 1Ohms





(4) Is the measured resistance within specifications ?
YES
> Go to "Component Inspection" procedure.
NO
> Repair or replace as necessary and then, go to "Verification of Vehicle Repair" procedure.

COMPONENT INSPECTION

1. Check Main Relay
(1) IG "OFF"
(2) Disconnect Main Relay
(3) Measure resistance between terminal 30 and 87 of Main Relay
(4) Measure resistance between terminal 86 and 85 of Main Relay.
Specification :









(5) Is the measured reisistance within specification ?
YES
> Substitute with a known - good PCM and check for proper operation.
If the problem is corrected, replace PCM and go to "Verification of Vehicle Repair" procedure.

NOTE:
There is a memory reset function on scantool that can erase optional parts automatically detected and memorized by PCM.

NO
> Substitute with a known - good Main Relay and check for proper operation.
If the problem is corrected, replace Main Relay and go to "Verification of Vehicle Repair"procedure.

VERIFICATION OF VEHICLE REPAIR

After a repair, it is essential to verify that the fault has been corrected.
1. Monitor and record the Freeze Frame Data for the Diagnostic Trouble Code(DTC) which has been diagnosed.
2. Using a Scantool, Clear the DTCs
3. Operate the vehicle within conditions noted in the freeze frame data or enable conditions
4. Monitor that all rediness test have been verified as " Complete "
5. Are any DTCs present ?
YES
> Go to the applicable troubleshoooting procedure.
NO
> System is performing to specification at this time.