Code P1378 – Low Voltage in Fuel Injection Control Module Circuit

Code P1378 Description

The diagnostic code P1378 indicates a problem with the fuel injection control module circuit having low voltage. The fuel injection control module (FICM) is an essential component of the fuel injection system in modern vehicles, responsible for controlling the operation of the fuel injectors. The FICM regulates the amount of fuel injected into the engine cylinders, ensuring optimal combustion and engine performance.

Common Causes of P1378

NOTE: The listed causes may not be a complete list of all potential problems, and there may be other causes.

1. Wiring harness issues
2. Loose connections
3. Faulty FICM relay
4. Faulty FICM
5. Electrical power failure

Symptoms of P1378

1. Engine misfires
2. Rough idle
3. Hesitation during acceleration
4. Poor fuel efficiency
5. Engine stalling

How to Fix P1378

1. Perform a thorough inspection of the wiring harness and connectors for any signs of damage or corrosion. Repair or replace as necessary.
2. Check and tighten all connections related to the FICM circuit to ensure a secure and reliable connection.
3. Test the proper operation of the FICM relay and replace it if faulty.
4. Check the FICM output voltage using a multimeter and replace the FICM if it does not meet the specified voltage requirements.
5. If the problem persists, inspect the FICM power supply and correct any electrical system faults.