warning light guide
ABS Warning Light
The anti-lock braking system has detected a fault and shut itself off to prevent unpredictable braking. Your normal brakes still stop the car, but your wheels can lock up and skid during emergency stops.
What it looks like: It appears as a steady amber circle with the letters ABS inside, often alongside the traction control light. If a red brake warning light comes on at the same time, stop driving immediately because the hydraulic brake system may have failed.
Updated 9 November 2026
Can I keep driving?
Service soon
Your standard brakes still stop the car in gentle driving, but anti-skid protection is disabled if you need to stop suddenly.
What to do right now
- 1Gently press the brake pedal in a safe spot to confirm it feels firm and operates normally.
- 2Increase your following distance behind other traffic, particularly on wet or slippery roads.
- 3Check your dashboard dials to confirm the red brake warning light is not also illuminated.
Likely causes
Most likely first.
- Likely
Faulty wheel speed sensor
Each wheel has a sensor exposed to road grime, salt and heat. When road dirt covers the tip or internal electronics fail, the computer loses wheel speed data and disables the system.
- Possible
Cracked or corroded reluctor ring
The toothed or magnetic tone ring on the wheel hub or driveshaft can crack from rust expansion. This creates an erratic speed pulse that the ABS module reads as an electrical glitch.
- Possible
Damaged sensor wiring
The thin wiring harness flexes with every turn of the steering wheel and bounce of the suspension. Over time, the internal copper wires can fatigue and snap or chafe against the wheel arch.
- Rare
Failed ABS pump or control module
Internal valves can stick or electronic solder joints inside the computer module can crack from heat cycles and vibration. A complete module failure prevents any automated hydraulic pressure control.
What you can check yourself
Park somewhere safe and level, engine off, before you start.
- 1
Check brake pedal feel
While stopped safely, press down firmly on the brake pedal. If the pedal feels spongy or slowly sinks towards the floor, stop driving because brake fluid pressure is escaping.
- 2
Inspect the brake fluid reservoir
Open the bonnet and locate the translucent brake fluid container near the bulkhead. Ensure the fluid sits comfortably between the minimum and maximum markings without removing the cap.
- 3
Look for damaged sensor cables
Turn the front wheels fully to one side on a flat surface and look behind the tyre with a torch. Check that the thin black wire running to the wheel hub is not torn, cut or rubbing against the tyre.
- 4
Check battery condition
Low electrical voltage during engine startup can trigger temporary ABS communication faults. If your engine cranks slowly, a failing 12-volt battery might be setting false system warnings.
Rough cost to fix
Rough estimateTypical prices in Ireland (€) and the UK (£), from an independent garage up to a main dealer. Prices depend mainly on whether the fault is an external wheel speed sensor or an electronic pump unit that requires coding to the car.
Wheel speed sensor replacement
- Do it yourself
- €30–90£25–80 in the UK
- At a garage
- €110–220£95–190 in the UK
ABS reluctor ring replacement
- Do it yourself
- Garage job
- At a garage
- €150–320£130–280 in the UK
ABS module rebuild or replacement
- Do it yourself
- Garage job
- At a garage
- €450–1,200£380–1,050 in the UK
When to go to a garage
- The red brake warning symbol lights up at the same time as the amber ABS light.
- The brake pedal feels spongy, sinks to the floor or requires unusual pressure to stop the car.
- The vehicle pulls sharply to one side whenever you apply the brakes.
- The ABS warning light stays on continuously across multiple journeys.
Questions drivers ask
Can I drive my car with the ABS light on?
Yes, you can usually drive to a garage if the pedal feels normal and no red brake warning lights are on. Your base hydraulic brakes will still stop the car, but the wheels may lock under heavy braking. Drive at moderate speeds and leave plenty of room between you and the car in front.
Will my car fail its NCT or MOT with the ABS light on?
Yes, an illuminated ABS warning light is an automatic failure on both the Irish NCT and the UK MOT. Testers check that the warning light illuminates during ignition and turns off once the engine starts. You must repair the fault and clear the diagnostic code before taking your test.
Why does the ABS light go off and then come back on?
Intermittent warnings usually indicate an erratic signal caused by dirt on a sensor, a loose electrical connector or a cracked reluctor ring. The system passes its initial self-test when parked, but detects missing speed pulses once the car reaches 20 km/h (12 mph) or encounters road bumps.
Can I reset the ABS light by disconnecting the battery?
Disconnecting the battery rarely solves the issue because the ABS computer checks all wheel sensors every time you turn the key. If an electrical fault remains present, the computer will detect it again within seconds and restore the warning light. A garage scan tool is needed to read the specific fault code and guide the repair.
Test rules here are for the National Car Test in Ireland (NCT) and the MOT in the UK. Elsewhere, check the regulations of your own country or state before going for a vehicle test.
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General guidance for most cars, not a diagnosis of yours. Details differ by make, model and year - check your handbook, and if in doubt, don't drive.