AutoCodes.com | All About OBDII Engine Codes
AutoCodes - Buick - C0378 Buick

C0378 Buick Code - Front Axle Switch Circuit Signal Invalid

- Code Popularity: 652 Views
- Repair Importance Level: 3/3
- Repair Difficulty Level: 3/3
Table of contents
Share on Facebook   Share on Twitter   Share on Linkedin

What are the Possible Causes of the DTC C0378 Buick?

NOTE: The causes shown may not be a complete list of all potential problems, and it is possible that there may be other causes.
  • Faulty Front Axle Switch/Actuator
  • Front Axle Switch/Actuator harness is open or shorted
  • Front Axle Switch/Actuator circuit poor electrical connection
⚠ Does your Buick have Safety Recalls? → Check here

How to Fix the DTC C0378 Buick?

Review the 'Possible Causes' mentioned above and visually examine the corresponding wiring harness and connectors. Ensure to check for any damaged components and inspect the connector pins for signs of being broken, bent, pushed out, or corroded.

Search for C0378 Buick Questions and Answers: Search here →

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the C0378 Buick code, it typically requires 1.0 hour of labor. The specific diagnosis time and labor rates at auto repair shops can differ based on factors such as the location, make and model of the vehicle, and even the engine type. It is common for most auto repair shops to charge between $75 and $150 per hour.

What are Code Possible Symptoms?

  • Anti-Lock Brake System (ABS) Warning Light ON
  • Engine Light ON (or Service Engine Soon Warning Light)

Code C0378 Buick Description

The front axle control circuit consists of an electric motor actuator which engages and disengages the front axle. The front axle actuator motor consists of a permanent magnetic motor, a worm gear controlled plunger, a front axle switch and an electronic control circuit within the actuator assembly. The axle switch signal circuit will have 12 volts when in any 4WD mode or AWD mode and 0 volts when in 2 high or neutral. The front axle actuator consists of the following circuits:
- The front axle control circuit, which is also connected to the transfer case shift control module
- The front axle switch circuit, which is also connected to the transfer case shift control module
- An ignition 3 voltage circuit
- A ground circuit
When a shift to AUTO 4WD, 4HI, or 4LO is requested, the transfer case shift control module engages the front axle by grounding the front axle control circuit through a current limiting driver. This DTC detects a short to ground, short to voltage or an open circuit on the switch signal circuit.

OBDII Code C0378 Buick - Front Axle Switch Circuit Signal Invalid - AutoCodes.com
C0378 Buick Code - Front Axle Switch Circuit Signal Invalid

Need More Information on the Code?

Need more information on how to fix the C0378 Buick code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the C0378 Buick code diagnosed by a professional: Find a repair shop in your area

Code C0378 Buick comments

Help us improve AutoCodes.com. Leave a comment below or tell us if the information above helps you fix the code. What are the symptoms on your vehicle for the C0378 Buick code? Have you replaced any parts?
Any information is appreciated. Thanks