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Engine-Codes – Generic – P1378

P1378 Code - Fuel Injection Control Module Circuit Low Voltage

Quick Answer

The diagnostic trouble code P1378 indicates a problem with the Fuel Injection Control Module Circuit having low voltage. Common causes include Wiring harness issues, Loose connections, Faulty FICM relay. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

What it means
P1378 indicates Fuel Injection Control Module Circuit Low Voltage.
Common causes
Common causes include Wiring harness issues, Loose connections, Faulty FICM relay.
Severity
High - diagnose this code as soon as possible.
Can I drive?
Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.
What is this?
Table of contents Created and updated by William Orellana on Sep 06, 2024
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Code P1378 Description

The diagnostic trouble code P1378 indicates a problem with the Fuel Injection Control Module Circuit having low voltage. The Fuel Injection Control Module (FICM) is a crucial component in the fuel injection system of modern vehicles, responsible for controlling the fuel injectors' operation. The FICM regulates the amount of fuel that is injected into the engine cylinders, ensuring optimal combustion and engine performance.

OBDII Code P1378 - Fuel Injection Control Module Circuit Low Voltage
P1378 Code - Fuel Injection Control Module Circuit Low Voltage

Common Causes of P1378

  1. Wiring harness issues
  2. Loose connections
  3. Faulty FICM relay
  4. Defective FICM
  5. Failing power supply

Symptoms of P1378

  1. Engine misfires
  2. Rough idling
  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 FICM relay for proper functionality and replace if faulty.
  4. Verify the FICM's voltage output using a multimeter and replace the FICM if it fails to meet the specified voltage requirements.
  5. If the issue persists, inspect the power supply to the FICM and address any faults in the electrical system.

Cost to Fix P1378

The typical repair costs for addressing a Fuel Injection Control Module Circuit Low Voltage issue can range from $200 to $600, including parts and labor. However, specific diagnosis time and labor rates at auto repair shops can vary based on factors such as location, vehicle make and model, and engine type. It's recommended to inquire about local rates to get a more accurate estimate for this repair.

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Code P1378 Information for Specific Makes

About the author: William Orellana is a Master Mechanic and Mechanical Engineer with over 30 years of experience diagnosing and repairing vehicles. Learn more about his background.

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