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 M-MDS to the DLC-2.
•  Clear the DTC from the PCM memory using the M-MDS.
•  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”.
(See INTERMITTENT CONCERN TROUBLESHOOTING [MZR-CD (RF Turbo)].)
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.
(See FUEL INJECTOR REMOVAL/INSTALLATION [MZR-CD (RF Turbo)].)
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 M-MDS.
•  Start the engine.
•  Is the PENDING CODE for this DTC present?
Yes
Replace the PCM, then go to the next step.
(See PCM REMOVAL/INSTALLATION [MZR-CD (RF Turbo)].)
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.
(See DTC TABLE [MZR-CD (RF Turbo)])
No
Troubleshooting completed.