Mazda Factory OBD-II DTC P0691 Code Diagnostic Procedure

P0691 Fan control module circuit low input
DETECTION CONDITION
•  The PCM monitors the fan control module signal. If the voltage at PCM terminal 318 remains low, the PCM determines that there is a fan control module circuit problem.
POSSIBLE CAUSE
•  Fan control module malfunction
•  Short to ground in the wiring harness between fan control module terminal 1C and PCM terminal 318
•  Connector or terminal malfunction
•  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 REPAIR INFORMATION AVAILABILITY
•  Verify related service repair information availability.
•  Is any related repair information available?
Yes
Perform repair or diagnosis according to the available repair 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”.
4
INSPECT FAN CONTROL MODULE CONNECTOR FOR POOR CONNECTION
•  Turn the engine switch off.
•  Disconnect the fan control module connector.
•  Inspect for poor connection (such as damaged/pulled-out pins, corrosion).
•  Is there any malfunction?
Yes
Repair or replace the terminal, then go to Step 8.
No
Go to the next step.
5
INSPECT FAN CONTROL MODULE
•  Inspect the fan control module.
•  Is there any malfunction?
Yes
Replace the fan control module, then go to Step 8
No
Go to the next step.
6
INSPECT PCM CONNECTOR FOR POOR CONNECTION
•  Turn the engine switch off.
•  Disconnect the PCM connector.
•  Inspect for poor connection (such as damaged/pulled-out pins, corrosion).
•  Is there any malfunction?
Yes
Repair or replace the terminal, then go to Step 8.
No
Go to the next step.
7
INSPECT FAN CONTROL MODULE CONTROL CIRCUIT FOR SHORT TO GROUND
•  Turn the engine switch off.
•  Disconnect the PCM connector.
•  Inspect for continuity between fan control module terminal 1C (wiring harness-side) and body ground.
•  Is there continuity?
Yes
Repair or replace the wiring harness for a possible short to ground, then go to the next step.
No
Go to the next step.
8
VERIFY THAT DTC P0691 TROUBLESHOOTING IS COMPLETED
•  Make sure to reconnect all disconnected connectors.
•  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
Replace the PCM, then go to the next step.
No
Go to the next step.
9
VERIFY AFTER REPAIR PROCEDURE
•  Perform the after repair procedure.
•  Are any DTCs present?
Yes
Go to the applicable DTC inspection.
No
DTC troubleshooting completed.
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