Symptoms
- One or more wheels stop spinning suddenly during braking
- Possible skidding or loss of steering control
- ABS light may or may not be on
Likely causes
- CommonABS system not functioning (light on or fault present)Without a working ABS, hard braking can lock wheels instead of the system modulating pressure.
- PossibleContaminated brake pad or rotor (oil, grease) causing that wheel to grab excessivelyUneven friction can make one wheel lock before the others.
- PossibleOverly aggressive or wrong-spec brake padsSome aftermarket pads bite too hard for the vehicle's original ABS calibration.
- Less commonRear brake proportioning issue (older vehicles without full ABS)Can cause rear wheels to lock before fronts on hard stops.
What to do
- Check if the ABS warning light is on, which would explain a lack of anti-lock function.
- Note which wheel or wheels seem to lock, if you can tell from skid marks or the car's behavior.
- Avoid slamming the brakes hard until this is checked, especially on wet or slippery roads.
- Have the code read if the ABS light is on, to identify the specific fault.
- Have a mechanic inspect pads and rotors for contamination or an incorrect pad compound.
- Have the ABS system or affected brake component repaired based on the diagnosis.
When to call a pro
See a mechanic promptly, since this affects your ability to stop safely and steer during hard braking.
Safety
Use caution
Locking wheels can cause loss of steering control, especially on wet or icy roads; drive cautiously and avoid hard braking until this is diagnosed and fixed.