ABS Warning Light On — Is It Safe to Drive?

The ABS warning light (usually a circle with ABS written inside it) means the anti-lock braking system has detected a fault and disabled itself. Your brakes will still work — you won't lose braking ability — but the ABS function that prevents wheel lockup during emergency stops will be inactive.

Is it safe to drive with the ABS light on?

Technically yes for short periods — your standard braking is unaffected. However, in an emergency stop, especially on wet or slippery roads, your wheels may lock up and you'll skid rather than brake in a controlled way. Stopping distances in emergencies will be longer without ABS.

More importantly, an illuminated ABS warning light is an automatic MOT failure on vehicles first registered after July 2015. On older cars, the tester notes it as an advisory.

Common causes:

Wheel speed sensor fault — the most common cause by far. Each wheel has a sensor that feeds speed data to the ABS module. When one fails or its wiring is damaged, the ABS system disables itself. Wheel speed sensor faults produce specific fault codes (C0035 for left front, for example) that pinpoint which sensor has failed. The sensor itself costs £15–40; the wiring is often the actual fault.

Damaged ABS reluctor ring — a toothed ring on the wheel hub that the sensor reads. Damaged teeth cause erratic signals. Usually visible once the wheel is removed.

Low brake fluid — if brake fluid is very low, it can trigger the ABS warning alongside the brake warning light. Check the brake fluid reservoir.

Faulty ABS module — less common but the ABS control module itself can fail. Symptoms include the light appearing without any wheel speed sensor codes.

Diagnosis:

An OBD2 scanner with ABS functionality will read the specific code. Basic cheap scanners often can't read ABS codes — you need a mid-range scanner or a garage with proper diagnostics. Most garages charge £40–60 for ABS fault reading and a quote.