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 DTC P1378 [MZR-CD (RF Turbo)]

DTC P1378 [MZR-CD (RF Turbo)]

id0102f1117600

DTC P1378

Fuel injector supply voltages circuit low input

DETECTION CONDITION

• The PCM monitors the supply voltage to the fuel injector. If the fuel injector supply voltage is less than 52.4 V when the engine switch is on, the PCM determines that there is a malfunction in the fuel injector circuit.
Diagnostic support note
• The MIL illuminates if the PCM detects the above malfunction condition during the first drive cycle.
• The FREEZE FRAME DATA is available.
• The DTC is stored in the PCM memory.

POSSIBLE CAUSE

• Fuel injector malfunction
• Connector or terminal malfunction
• Short to ground in the wiring harness between the fuel injector No.1 terminal B and PCM terminal 42
• Short to ground in the wiring harness between the fuel injector No.2 terminal B and PCM terminal 21
• Short to ground in the wiring harness between the fuel injector No.3 terminal B and PCM terminal 23
• Short to ground in the wiring harness between the fuel injector No.4 terminal B and PCM terminal 40
• PCM malfunction

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 the 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 PENDING CODE for this DTC present?
Yes
Go to the next step.
No
Intermittent concern exists.
Perform the "INTERMITTENT CONCERN TROUBLESHOOTING".
4
INSPECT FUEL INJECTOR CONNECTOR FOR POOR CONNECTION
• Turn the engine switch to the ON position.
• 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 FUEL INJECTORS CIRCUIT FOR SHORT TO GROUND
• Turn the engine switch to off.
• Inspect for continuity between fuel injector terminal B and ground.
• Is there continuity?
Yes
Repair or replace the wiring harness for a short to ground, then go to Step 8.
No
Go to the next step.
6
INSPECT FUEL INJECTOR
• Inspect the fuel injector.
• Is there any malfunction?
Yes
Replace the fuel injector, then go to Step 8.
No
Go to the next step.
7
INSPECT PCM CONNECTOR FOR POOR CONNECTION
• Turn the engine switch to 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 TROUBLESHOOTING OF DTC P1378 COMPLETED
• Make sure to reconnect all disconnected connectors.
• Clear the DTC from the PCM memory using the WDS or equivalent.
• Start the engine.
• Is the PENDING CODE for this 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 Repair Verification Drive Mode.
• Are any DTCs present?
Yes
Go to the applicable DTC inspection.
No
Troubleshooting completed.