ABS Warning Light Explained
What the ABS light means, common causes, and whether it affects your MOT.
The ABS light warns you that the anti-lock braking system isn't functioning correctly, even though your normal brakes usually still work. It's a warning worth taking seriously, particularly in wet conditions where ABS matters most.
How the fault often shows up
- The ABS light stays on after starting the car
- The light comes on while driving, often over bumps
- The brake pedal feels different or pulses unexpectedly
- The light appears alongside the traction control warning
- The light flickers intermittently, especially in wet weather
Common causes
- A faulty wheel speed sensor, often affected by dirt or a damaged tone ring
- Damaged or corroded wiring to a sensor
- A fault within the ABS control module itself
- Low brake fluid level triggering the warning
- A failing ABS pump or hydraulic unit
How it's diagnosed
We scan the ABS control unit for stored fault codes, which usually points directly to the affected wheel sensor or circuit. Most wheel speed sensor faults are confirmed and repaired within an hour.
Is it safe to keep driving?
Your normal brakes will still work with the ABS light on, but you'll lose the anti-lock function that prevents wheel lock-up under hard braking — a real risk on wet or icy roads. It's also an automatic MOT failure, so it's worth resolving promptly.
Frequently asked questions
Yes, your regular brakes still function, but you lose the anti-lock protection that helps you steer while braking hard.
ABS light on? We can diagnose it on your driveway.