DTC P0685 [WL-C, WE-C (Australian, European (L.H.D. U.K.) specs.)]

id0102c4956100

DTC P0685

Main relay control circuit open
DETECTION CONDITION
•  The PCM monitors the power supply to the PCM. If the power supply is shut down several times when the engine switch is turned to the ON position, the PCM determines that there is a power circuit malfunction (open circuit).
POSSIBLE CAUSE
•  Connector or terminal malfunction
•  Open circuit in wiring harness between main relay terminal B and PCM terminal 219
•  Open circuit in wiring harness between main relay terminal D and PCM terminal 201, 203, or 205
•  Main relay malfunction
•  Open circuit in wiring between main relay terminal A, terminal C and battery
•  PCM malfunction

Diagnostic procedure

STEP

INSPECTION

ACTION
1
VERIFY FREEZE FRAME DATA HAS BEEN RECORDED
•  Has the FREEZE FRAME DATA been recorded?
Yes
Go to the next step.
No
Record the FREEZE FRAME DATA on the repair order, then go to the next step.
2
VERIFY RELATED SERVICE INFORMATION AVAILABILITY
•  Verify related service information availability.
•  Is any related service information available?
Yes
Perform repair or diagnosis according to the available service information.
•  If the vehicle is not repaired, go to the next step.
No
Go to the next step.
3
VERIFY CURRENT SIGNAL STATUS: IS CONCERN INTERMITTENT OR CONSTANT?
•  Connect the M-MDS to the DLC-2.
•  Clear the DTC from the PCM memory using the M-MDS.
•  Run the vehicle under the FREEZE FRAME DATA stored condition.
•  Is the same DTC present?
Yes
Go to the next step.
No
Intermittent concern exists.
Perform the “INTERMITTENT CONCERNS TROUBLESHOOTING”.
(See INTERMITTENT CONCERN TROUBLESHOOTING [WL-C, WE-C].)
4
INSPECT MAIN RELAY CONNECTOR FOR POOR CONNECTION
•  Disconnect the generator connector.
•  Inspect for poor connection (damaged, pulled-out terminals, corrosion, etc.).
•  Is there a malfunction?
Yes
Repair or replace the terminals, then go to Step 9.
No
Go to the next step.
5
INSPECT MAIN RELAY POWER CIRCUIT FOR OPEN CIRCUIT
•  Measure the voltage between the following terminal:
―  Main relay terminal A and body ground.
―  Main relay terminal C and body ground.
•  Is the voltage B+?
Yes
Go to the next step.
No
Repair or replace the wiring harness for open circuit, then go to Step 9.
6
INSPECT MAIN RELAY
•  Inspect the main relay.
•  Is there any malfunction?
Yes
Replace the main relay, then go to Step 9.
No
Go to the next step.
7
INSPECT PCM CONNECTOR FOR POOR CONNECTION
•  Turn the engine switch off.
•  Disconnect the PCM connector.
•  Inspect for poor connection (damaged, pulled-out terminals, corrosion, etc.).
•  Is there a malfunction?
Yes
Repair terminals, then go to Step 9.
No
Go to the next step.
8
INSPECT MAIN RELAY CONTROL CIRCUIT FOR OPEN CIRCUIT
•  Inspect for continuity between the following terminal:
―  Main relay terminal B and PCM terminal 219
―  Main relay terminal D and PCM terminal 201, 203, or 205
•  Is there continuity?
Yes
Go to the next step.
No
Repair or replace the wiring harness for open circuit, then go to Step 9.
9
VERIFY THAT DTC P0685 TROUBLESHOOTING IS COMPLETED
•  Turn the engine switch off.
•  Make sure to reconnect all disconnected connectors.
•  Turn the engine switch to the ON position (Engine off).
•  Clear the DTC from the memory using the M-MDS.
•  Run the vehicle under the FREEZE FRAME DATA stored condition.
•  Is the same DTC present?
Yes
Replace PCM, then go to the next step.
(See PCM REMOVAL/INSTALLATION [WL-C, WE-C].)
(See PCM REMOVAL/INSTALLATION (U.K. Specs.) [WL-C, WE-C].)
No
Go to the next step.
10
VERIFY AFTER REPAIR PROCEDURE
•  Perform the “After Repair Procedure“.
•  Are any DTCs present?
Yes
Go to the applicable DTC inspection.
(See DTC TABLE [WL-C, WE-C (Australian, European (L.H.D. U.K.) specs.)].)
No
DTC troubleshooting completed.