DTC P1392 [MZR-CD (RF Turbo)]

id0102f1837200

DTC P1392

Glow plug circuit high input
DETECTION CONDITION
•  The PCM monitors the output signal to the glow relay when the glow relay is off. If the glow relay voltage is 4.8 V or more when the glow relay is off, The PCM determines that there is a malfunction in the glow relay control circuit.
POSSIBLE CAUSE
•  Glow plug relay malfunction
•  Glow plug malfunction
•  PCM malfunction
•  Connector or terminal malfunction
•  Short to power supply in wiring harness between glow plug relay terminal A and PCM terminal 75
•  Short to power supply in wiring harness between glow plug relay terminal C and PCM terminal 37

Diagnostic procedure

STEP

INSPECTION

ACTION
1
VERIFY FREEZE FRAME DATA HAS BEEN RECORDED
•  Has 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.
•  Start the engine.
•  Is the same DTC present?
Yes
Go to the next step.
No
Intermittent concern exists.
Perform the “INTERMITTENT CONCERN TROUBLESHOOTING”.
(See INTERMITTENT CONCERN TROUBLESHOOTING [MZR-CD (RF Turbo)].)
4
INSPECT GLOW PLUG RELAY CONNECTOR FOR POOR CONNECTION
•  Turn the engine switch off.
•  Disconnect the glow plug relay 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 the next step.
No
Go to the next step.
5
INSPECT GLOW PLUG RELAY
•  Inspect the glow plug relay.
•  Is there any malfunction?
Yes
Replace the glow plug relay, go to Step 9.
No
Go to the next step.
6
INSPECT GLOW PLUG RELAY SIGNAL CIRCUIT FOR SHORT TO POWER
•  Turn the engine switch to the ON position (Engine off).
•  Disconnect the PCM connector.
•  Measure the voltage between glow plug terminal A and body ground.
•  Is the voltage more than 4.8 V?
Yes
Repair or replace the wiring harness for a short to power supply, then go to Step 9.
No
Go to the next step
7
INSPECT GLOW PLUG
•  Inspect glow plug.
•  Is there any malfunction?
Yes
Replace the glow plug, go to Step 9.
No
Go to the next step.
8
INSPECT POOR CONNECTION OF PCM CONNECTOR
•  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 suspected terminal, go to the Step 10.
No
Go to the next step.
9
INSPECT GLOW PLUG RELAY GROUND CIRCUIT FOR SHORT TO POWER
•  Turn the engine switch to off.
•  Remove the glow plug relay.
•  Measure the voltage between glow plug relay terminal C and body ground.
•  Is the voltage B+?
Yes
Repair or replace the wiring harness for a short to power supply, then go to the next step.
No
Go to the next step
10
VERIFY TROUBLESHOOTING OF DTC P1392 COMPLETED
•  Make sure to reconnect all disconnected connectors.
•  Clear the DTC from the PCM memory using the M-MDS.
•  Start the engine and warm it up to the normal operating temperature.
•  Is the same DTC present?
Yes
Replace the PCM, go to the next step.
(See PCM REMOVAL/INSTALLATION [MZR-CD (RF Turbo)].)
No
Go to the next step.
11
VERIFY AFTER REPAIR PROCEDURE
•  Perform the Repair Verification Drive Mode.
•  Is any DTC present?
Yes
Go to the applicable DTC inspection.
(See DTC TABLE [MZR-CD (RF Turbo)].)
No
Troubleshooting completed.