Mazda Factory OBD-II DTC P1631 Code Diagnostic Procedure

Mazda P1631 PCM control relay (power hold)
DETECTION CONDITION
•  The PCM monitors the input voltage from the PCM control relay signal. If the voltages at PCM terminal 241 deviates from the threshold, the PCM determines that the there is a PCM control relay circuit malfunction.
POSSIBLE CAUSE
•  PCM control relay malfunction
•  Connector or terminal malfunction
•  Short to power supply in the wiring harness between PCM control relay terminal D and PCM terminal 241
•  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 PCM CONTROL RELAY CONNECTOR FOR POOR CONNECTION
•  Turn the engine switch off.
•  Inspect for poor connection (such as damaged/pulled-out terminals, corrosion).
•  Is there any malfunction?
Yes
Go to the next step.
No
Repair or replace the terminal, then go to Step 8.
5
INSPECT PCM CONTROL RELAY SIGNAL CIRCUIT SHORT TO POWER SUPPLY
•  Turn the engine switch to the ON position.
•  Measure the voltage between PCM control relay terminal D and body ground.
•  Is the voltage B+?
Yes
Repair or replace the wiring harness for a short to power supply, then go to Step 8.
No
Go to the next step.
6
INSPECT PCM CONTROL RELAY
•  Inspect the PCM control relay.
•   Is there any malfunction?
Yes
Replace the intake shutter solenoid valve, then go to Step 8.
No
Go to the next step.
7
INSPECT PCM CONNECTOR FOR POOR CONNECTION
•  Turn the engine switch off.
•  Inspect for poor connection (such as damaged/pulled-out terminals, corrosion).
•  Is there any malfunction?
Yes
Repair or replace the terminal, then go to the next step.
No
Go to the next step.
8
VERIFY THAT DTC P1631 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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