Hill descent control warning light

Symptoms

• Hill descent control icon lit or flashing
• System doesn't seem to slow the vehicle when activated on a hill
• Often paired with a traction control or ABS light

Likely causes

• CommonFaulty wheel speed sensorHill descent control shares sensors with ABS and traction control.
• CommonABS or traction control fault disabling related systemsThese systems are interconnected, so one fault can disable several features.
• PossibleLow brake fluidThe system uses the brakes to control descent speed, so fluid issues can affect it.
• Less commonSoftware or module faultLess common but possible on complex four-wheel-drive systems.

What to do

1. Check if the ABS or traction control lights are also on, since they often share a root cause.
2. Check the brake fluid level and top off if low.
3. Use manual braking and lower gears on steep descents until the system is repaired.
4. Have the code read at a shop, since hill descent control faults are usually tied to another system's code.
5. Address whichever sensor or fluid issue is flagged in the scan.
6. Test the system again on a gentle slope after repairs, in a safe area.

When to call a pro

See a mechanic to diagnose the underlying sensor or fluid issue, especially before off-road or mountain driving.

Safety