C0631
Front Axle Disconnect Actuator
Generic fault on front axle disconnect actuator. The disconnect decouples the front axle from the drivetrain to save fuel in 2WD mode.
- Check engine light: Yes
- Emissions related: No
- Repair difficulty: hard
Symptoms
- ABS warning light on
- ESC/stability control deactivated
- Possible reduced brake assist
- Speedometer may behave erratically
Common causes
Ordered by how often each turns out to be the cause.
- Actuator failedCommon
Parts involved
- Front Axle Disconnect Actuator
C0631 is a generic OBD-II code defined by SAE J2012. Exact wording and diagnostic procedure vary by manufacturer and model. Code definitions are drawn from the public-domain OBDex dataset; the workshop notes are our own.