DTC P1378:00 [MZR-CD 2.2]

id0102f3149300

DTC P1378:00

Fuel injector supply voltage 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 ignition switch is on, the PCM determines that there is a malfunction in the fuel injector circuit.
MONITORING CONDITIONS
―  Battery voltage: 8 V or more
―  Time from switch the ignition to on: 2 s or more
Diagnostic support note
•  The MIL illuminates if the PCM detects the above malfunction condition during the first drive cycle.
•  FREEZE FRAME DATA (Mode 2)/Snapshot data is available.
•  The DTC is stored in the PCM memory.
POSSIBLE CAUSE
•  Fuel injector connector or terminals malfunction
•  Fuel injector malfunction
•  Short to ground in wiring harness between the following terminals:
―  Fuel injector No.1 terminal A—PCM terminal 1D
―  Fuel injector No.2 terminal A—PCM terminal 1A
―  Fuel injector No.3 terminal A—PCM terminal 1B
―  Fuel injector No.4 terminal A—PCM terminal 1C
•  PCM connector or terminals malfunction
•  PCM malfunction

Diagnostic procedure

STEP

INSPECTION

ACTION
1
VERIFY FREEZE FRAME DATA (MODE 2)/SNAPSHOT DATA HAS BEEN RECORDED
•  Has the FREEZE FRAME DATA (Mode 2)/snapshot data been recorded?
Yes
Go to the next step.
No
Record the FREEZE FRAME DATA (Mode 2)/snapshot data on the repair order, then go to the next step.
2
VERIFY RELATED SERVICE INFORMATION AVAILABILITY
•  Verify related Service Information availability.
•  Is any related Service Information available?
Yes
Perform repair or diagnosis according to the available Service Information.
•  If the vehicle is not repaired, go to the next step.
No
Go to the next step.
3
VERIFY CURRENT INPUT SIGNAL STATUS IS CONCERN INTERMITTENT OR CONSTANT
•  Clear the DTC from the PCM memory using the M-MDS.
•  Start the engine.
•  Perform the KOER self test.
•  Is the same DTC present?
Yes
Go to the next step.
No
Intermittent concern exists.
•  Perform the “INTERMITTENT CONCERN TROUBLESHOOTING” procedure.
4
INSPECT FUEL INJECTOR CONNECTORS CONDITION
•  Switch the ignition to off.
•  Disconnect the fuel injector connectors.
•  Inspect for poor connection (such as damaged/pulled-out pins, corrosion).
•  Is there any malfunction?
Yes
Repair or replace the suspected connector and/or terminals, then go to Step 8.
No
Go to the next step.
5
INSPECT FUEL INJECTOR
•  Inspect the fuel injectors for all cylinders.
•  Is there any malfunction?
Yes
Replace the malfunctioning fuel injector, then go to Step 8.
(See FUEL INJECTOR REMOVAL/INSTALLATION [MZR-CD 2.2].)
No
Go to the next step.
6
INSPECT FUEL INJECTOR CIRCUITS FOR SHORT TO GROUND
•  Fuel injector connectors are disconnected.
•  Inspect for continuity between the following terminals (wiring harness-side) and body ground:
―  Fuel injector No.1 terminal A
―  Fuel injector No.2 terminal A
―  Fuel injector No.3 terminal A
―  Fuel injector No.4 terminal A
•  Is there continuity?
Yes
If the short to ground circuit could be detected:
•  Repair or replace the wiring harness for a possible short to ground.
If the short to ground circuit could not be detected:
•  Replace the PCM (short to ground in the PCM internal circuit).
Go to Step 8.
No
Go to the next step.
7
INSPECT PCM CONNECTOR CONDITION
•  Disconnect the PCM connector.
•  Inspect for poor connection (such as damaged/pulled-out pins, corrosion).
•  Is there any malfunction?
Yes
Repair or replace the connector and/or terminals, then go to the next step.
No
Go to the next step.
8
VERIFY DTC TROUBLESHOOTING COMPLETED
•  Make sure to reconnect all disconnected connectors.
•  Clear the DTC from the PCM memory using the M-MDS.
•  Start the engine.
•  Perform the KOER self test.
•  Is the same DTC present?
Yes
Replace the PCM, then go to the next step.
(See PCM REMOVAL/INSTALLATION [MZR-CD 2.2].)
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.
(See DTC TABLE [MZR-CD 2.2].)
No
DTC troubleshooting completed.