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DTC P1392 [MZR-CD (RF Turbo)]

BME010201300203

DTC P1392 | Glow plug circuit high input
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DETECTION CONDITION | • The PCM monitors the output signal to the glow relay when the glow relay is off. If the glow relay voltage is 4.0 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 B and PCM terminal 68
• Short to power supply in wiring harness between glow plug relay terminal A and PCM terminal 86

Diagnostic procedure

STEP | INSPECTION | ACTION
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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 WDS or equivalent to the DLC-2. • Clear the DTC from the PCM memory using the WDS or equivalent. • 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. (See RELAY INSPECTION.) • Is there any malfunction? | Yes | Replace 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 GND. • Is the voltage more than 4.0 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. (See GLOW PLUG INSPECTION [MZR-CD (RF Turbo)].) • Is there any malfunction? | Yes | Replace glow plug relay, 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 GRAND 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 GND. • 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 WDS or equivalent. • 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.
No | Go to the next step.
11 | VERIFY AFTER REPAIR PROCEDURE • Perform the Repair Verification Drive Mode. (See OBD DRIVE MODE [MZR-CD (RF Turbo)].) • Is any DTC present? | Yes | Go to the applicable DTC inspection. (See DTC TABLE [MZR-CD (RF Turbo)].)
No | Troubleshooting completed.