C0378 Code: Meaning, Causes, and Symptoms | OBD2 Codes
C0378 – Front Axle Switch Circuit Signal Invalid
C0378 Possible Symptoms
Anti-Lock Brake System (ABS) Warning Light ON,Engine Light ON (or Service Engine Soon Warning Light)
C0378 Possible Causes
Faulty Front Axle Switch/Actuator,Front Axle Switch/Actuator harness is open or shorted,Front Axle Switch/Actuator circuit poor electrical connection
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.