If your ABS light stays on after you start the car, the anti-lock brake system has found a fault and has usually turned off its anti-lock function until it's fixed. Your regular brakes should still work, but the wheels can lock up in a hard stop, especially on wet roads. If the ABS light comes on together with the red BRAKE light, or the pedal feels different, stop driving and have it checked right away. Hillside Auto Clinic at 26122 Western Ave, Lomita, CA 90717 can read the codes and find the cause; call (310) 956-5794 or schedule.
What the ABS does
When you brake hard, a wheel can stop turning while the car is still moving. A locked wheel skids, and a skidding front wheel can't steer. The anti-lock brake system watches each wheel with a speed sensor. If one wheel starts slowing much faster than the others, the ABS module rapidly releases and reapplies brake pressure to that wheel so it keeps turning. That's the pulsing or buzzing you may feel through the pedal in a panic stop, and it's normal.
On most modern cars, the same sensors and module also run traction control (which limits wheel spin when you accelerate) and stability control (which helps keep the car from sliding sideways in a turn). That's why the ABS light and the traction control light often come on together.
What the ABS light normally does
The ABS light, usually an amber circle with "ABS" inside, should come on for a few seconds when you start the car while the system checks itself, then go out. A problem is when:
- The ABS light stays on after startup.
- The ABS light comes and goes while driving, often over bumps or in the rain, which can point to a loose connection or damaged wiring.
- The traction control light stays on or the "TRAC OFF" or skid-car symbol won't go out.
- The traction control light flashes briefly while you're driving. That usually just means the system is working to stop wheel spin, not that something is broken.
ABS light vs. the red BRAKE light
These are two different warnings:
- ABS light (amber): the anti-lock system has a fault. Normal braking should still work.
- BRAKE light (red): the parking brake is on, the brake fluid is low, or there's a problem with the main hydraulic brake system.
If the red BRAKE light is on with the parking brake fully released, or both lights are on at once, the problem may affect normal braking. Pull over safely and have the car checked before driving further.
Common causes of an ABS or traction control light
- A bad wheel speed sensor. This is one of the most common causes. The sensors sit near each wheel, where they take a beating from heat, water, road grime, and brake dust.
- Damaged sensor wiring. The wires run along the suspension and flex every time the wheel moves, so they can rub through, crack, or get corroded connectors.
- A dirty or damaged tone ring. The sensor reads a toothed ring on the axle or hub. Rust, debris, or a cracked ring can throw off the reading.
- A worn wheel bearing or hub. On many cars the speed sensor is built into the hub, so a worn wheel bearing can trigger the light.
- Low brake fluid. Some cars turn on the ABS light along with the brake light when the fluid level drops, which can mean worn brake pads or a leak.
- A blown fuse or bad relay for the ABS pump or module.
- A faulty ABS module or pump. Less common, but it happens, sometimes from internal corrosion. Keeping up with brake fluid service helps protect these parts.
- Low battery voltage. A weak battery or charging problem can set ABS faults on some cars.
- Mismatched tire sizes. Tires of different sizes, or one badly underinflated tire, spin at different speeds and can confuse the system. If your tire pressure light is also on, check the tires first.
- Recent brake or suspension work where a sensor wire wasn't reconnected or got pinched.
Is it safe to drive with the ABS light on?
If only the amber ABS light is on and the brakes feel normal, you can usually drive carefully to get it checked. Just remember the anti-lock and traction control features may not help you in an emergency. Until it's fixed:
- Leave more following distance, especially on the 110, the 405, and PCH.
- Brake earlier and more gently, and take extra care when roads are wet. The first rains of the season leave South Bay streets slick with oil and dust.
- Accelerate gently from stops and in turns, since traction control may not step in.
Get it checked right away if the red BRAKE light is also on, the pedal feels soft or sinks, you hear grinding, or the car pulls hard when you brake.
Can I just clear the code?
Clearing the light without fixing the cause doesn't restore the anti-lock function. If the fault is still there, the light will come back, sometimes right away and sometimes after the next drive. The right fix is to read the stored ABS codes, find which sensor or circuit set them, repair it, and confirm the light stays off on a test drive.
Does the ABS light affect a California SMOG check?
The SMOG check looks at emissions systems, so an ABS light by itself isn't part of the test. It's still a safety issue worth fixing.
What we check
A basic code reader often can't read the ABS system, so a technician uses a scan tool that can pull ABS codes and watch live wheel speed data from all four wheels. That shows which sensor is reading wrong or dropping out. From there we inspect the sensor, its wiring and connector, the tone ring, the wheel bearing, brake fluid level, fuses, and battery voltage. We'll explain what we found and your options before any work is done.
Hillside Auto Clinic is open Monday–Friday 8 AM–6 PM and Saturday 10 AM–3 PM (closed Sunday). Visit us at 26122 Western Ave, Lomita, CA 90717, call (310) 956-5794, or email hillsideautoclinic@gmail.com.
Call or schedule
ABS or traction control light on in Lomita, Torrance, Harbor City, or anywhere in the South Bay? Call (310) 956-5794 or book online.
FAQ
What does the ABS light mean?
It means the anti-lock brake system found a fault and has likely turned off its anti-lock function. Your regular brakes should still work, but the wheels may lock up in a hard stop.
Why are my ABS and traction control lights on at the same time?
On most modern cars, both systems use the same wheel speed sensors and control module. When one sensor or the module has a problem, both features usually shut off and both lights come on.
Can a bad wheel bearing cause the ABS light?
Yes. On many cars the wheel speed sensor is part of the hub assembly, so a worn bearing or damaged hub can throw off the sensor reading.
Will the ABS light go off by itself?
Sometimes an intermittent fault makes the light come and go, but the underlying problem is usually still there. If the light comes on even once, it's worth having the codes read.
Can low brake fluid turn on the ABS light?
On some cars, yes, usually along with the red BRAKE light. Low fluid can mean worn pads or a leak, so have the brakes inspected rather than just topping it off.
