ABS warning light on
How it can appear on an MOT certificate
- “Anti-lock braking system warning lamp indicates a malfunction”
- “ABS warning lamp inoperative”
What it is
The anti-lock braking system (ABS) stops the wheels locking under hard braking so you can still steer. A warning light on the dashboard shows when the system has detected a fault.
Why it matters
With ABS faulty, the normal brakes usually still work, but the wheels can lock in an emergency stop, especially on wet or icy roads. A lit ABS light is an MOT fail.
What to check when viewing a car
The ABS light should come on briefly when you turn the ignition on, then go out. If it stays on, a garage can read the fault code. A common cause is a wheel speed sensor.
Has the car you're looking at had this before?
Free: every MOT, every defect explained in plain English, mileage, tax and ULEZ.
What the MOT categories mean
- Dangerous
- A direct and immediate risk to road safety, or a serious impact on the environment. The car fails and shouldn't be driven until it's repaired.
- Major
- It may affect the car's safety, put other road users at risk or harm the environment. The car fails and should be repaired straight away.
- Minor
- No significant effect on safety or the environment. The car passes, but it should be repaired as soon as possible.
- Advisory
- Something to keep an eye on that could need repairing in future. The car passes.
Related: brakes
- Brake pads wearing thin
- Brake discs worn, pitted or scored
- Brake pipe corroded
- Brake hose damaged or deteriorated
- Parking brake (handbrake) not working well enough
- Brakes pulling or uneven (imbalance)
Buying a used car?
General information about this type of MOT defect, not advice about a particular car. How serious it is depends on the car; have any car you're buying inspected by a qualified mechanic.