ABS and Traction Control Light On: Causes and Fixes
Diagnose simultaneous ABS and traction control lights. Common causes include wheel-speed sensors, wiring, or low voltage. Learn safe driving limits, step-by-step diagnosis, and fixes to restore stability systems effectively.
Quick Answer
When the ABS and traction control lights stay on together, the vehicle has usually lost data or control needed by both systems. A wheel-speed sensor circuit is a common cause, but damaged wiring, a tone ring or magnetic encoder, wheel-bearing play, mismatched tires, a steering-angle or yaw-sensor issue, low system voltage, a fuse, or an ABS module fault can produce the same warning. Normal brakes may still work, but ABS, traction control, and stability control may be limited. Check brake operation first, then scan the ABS module before replacing a sensor.
Safety note: Stop driving and arrange service if the red brake warning light is also on, the pedal is soft or sinks, brake fluid is leaking, the vehicle pulls strongly while braking, or grinding and wheel looseness are present. If normal braking feels firm but the amber ABS and traction lights remain on, drive only as necessary, increase following distance, and avoid high speed or slippery conditions.
Why Do the ABS and Traction Control Lights Come On Together?
ABS prevents wheel lock during hard braking. Traction control reduces wheelspin during acceleration, and electronic stability control may brake individual wheels to help the vehicle follow the driver’s intended path. Although their jobs differ, these systems share wheel-speed information, the ABS hydraulic unit, and parts of the control network.
If the control module cannot trust one of those inputs, it may disable several functions rather than act on incorrect data. That is why two or three amber warning lights can come from one failed signal instead of multiple unrelated failures.
A flashing traction-control light is not always a fault
A traction or “slip” light that flashes briefly while accelerating on rain, snow, gravel, or loose ground usually means the system is actively limiting wheelspin. A light that stays on after the road is clear—or appears together with the ABS light—usually means the system is switched off, unavailable, or has detected a fault. Also confirm that traction control was not intentionally turned off with the dashboard switch.
Can You Drive With the ABS and Traction Control Lights On?
It depends on what else the vehicle is doing. With only amber ABS and traction-control lights, conventional braking often remains available, but the electronic safety aids may not assist during a panic stop or loss of grip. Wheels may lock during hard braking, and the vehicle may be harder to stabilize on wet, snowy, or icy roads.
- A short cautious trip may be reasonable: the pedal is firm, braking is straight and predictable, no red brake warning appears, and there are no leaks, grinding noises, or loose-wheel symptoms.
- Stop driving: the red brake light is on, fluid is below the minimum mark, the pedal feels soft, stopping behavior changes, a wheel growls or feels loose, or several electrical systems fail at once.
Do not test ABS by making an emergency stop on a public road. If driving to a repair location is necessary, reduce speed, allow extra distance, avoid abrupt steering and braking, and choose dry conditions when possible.
What Causes Both the ABS and Traction Control Lights to Stay On?
| Likely cause | Clues that make it more likely |
|---|---|
| ABS wheel speed sensor or wheel-end wiring fault | A code identifies one wheel; its live speed reads zero, spikes, or drops out; the light changes after turning, bumps, or wet weather |
| Damaged tone ring, magnetic encoder, debris, or incorrect sensor gap | False ABS activation near a slow stop; a repeating dropout once per wheel revolution; rust, cracks, missing teeth, or magnetic-ring damage |
| Wheel bearing or hub assembly problem | Humming that changes with road speed or turning, wheel play, or an integrated sensor/encoder signal affected by the hub |
| Wrong tire size, very uneven tread, or incorrect tire pressure | The lights appeared after one tire was replaced, a spare was installed, or tire work changed the rolling circumference |
| Steering-angle, yaw-rate, or acceleration-sensor fault or lost calibration | The stability light joins the other warnings; the issue followed alignment, steering work, or battery disconnection; scan data disagrees with vehicle position |
| Low voltage, charging fault, blown fuse, poor ground, or communication issue | Hard starting, dim lights, multiple warning messages, recent dead battery or jump-start, or loss-of-communication and voltage codes |
| ABS hydraulic/control module fault | Module power and grounds are correct, wheel inputs are valid, and codes point to internal pump, valve, processor, or communication failure |
Low brake fluid deserves a separate safety check. Fluid level can fall from a leak or as brake pads wear, and some vehicles illuminate a brake warning that may disable related stability functions. Do not simply top off a low reservoir without finding why the level dropped. Use only the fluid type specified for the vehicle, and treat a leak or soft pedal as a stop-driving condition.
What Does the Timing of the Warning Lights Tell You?
| When the lights appear | Start with this check |
|---|---|
| They stay on immediately after startup | Module power, fuses, voltage, stored hard-circuit faults, and communication |
| They appear only after the vehicle starts moving | Live wheel-speed agreement, tire size, sensor gap, encoder/tone ring, and hub condition |
| They appear during slow braking with pedal pulsation | A wheel-speed signal dropping to zero too early because of gap, rust, encoder, bearing, or sensor issues |
| They appeared after tire, bearing, brake, axle, or suspension work | Disconnected or pinched wiring, incorrect routing, damaged encoder, wrong hub option, tire mismatch, or missed calibration |
| They appeared after a dead battery, jump-start, or replacement | Battery and charging voltage, low-voltage codes, grounds, and any required steering-angle relearn |
How Do You Diagnose ABS and Traction Control Lights Step by Step?
- Check the dashboard and brake feel. Separate amber ABS/traction warnings from a red brake warning. Confirm that the traction-control switch was not intentionally turned off. Note pedal feel, noises, pulling, and exactly when the lights appear.
- Check the simple vehicle conditions. Verify brake-fluid level without opening a clean translucent reservoir unnecessarily. Compare all tire sizes, pressures, and obvious tread differences. Look for recent service that may have disturbed wheel-end wiring.
- Test system voltage and fuses. Follow the owner’s manual and wiring diagram. A blown replacement fuse that fails again indicates an electrical fault; do not install a higher-amperage fuse.
- Scan the ABS module—not only the engine computer. Use an OBD2 scanner with ABS access. A basic emissions-code reader may report no codes even while ABS codes are stored. Record every code and freeze-frame or failure-record detail before clearing it.
- Compare live wheel-speed data. At a safe low speed, all four readings should rise smoothly and agree closely when traveling straight. A sensor that remains at zero suggests a circuit or sensor fault; one that drops out or spikes can point to wiring, gap, encoder, debris, or bearing movement.
- Inspect the indicated wheel from connector to encoder. Look for broken clips, stretched or rubbed wire, backed-out pins, corrosion, debris, sensor seating, and visible tone-ring damage. Check the bearing and hub using the vehicle-specific procedure. Magnetic encoder rings can be damaged without obvious toothed-ring defects.
- Test the sensor type correctly. Passive and active wheel-speed sensors use different circuits and test methods. Do not apply one universal resistance value. Use the vehicle wiring diagram, specified power/ground checks, signal testing, and—where necessary—an oscilloscope.
- Verify the complete repair. Correct the confirmed fault, route wiring through the original retainers, clear codes when instructed, perform required calibrations, and road-test under the condition that originally triggered the lights. Recheck live data and pending codes.
Do not replace the wheel speed sensor only because its wheel is named in a code. The code identifies the affected signal path. The actual failure can be the sensor, connector, harness, tone ring, encoder, sensor gap, hub bearing, module circuit, or even an incorrect wheel-end part installed previously.
How Do You Fix the ABS and Traction Control Lights?
The lights go out only after the underlying fault is corrected and the system completes its self-check. Depending on the diagnosis, the repair may involve:
- Repairing a damaged wheel-end harness, terminal, connector, power supply, or ground
- Cleaning and correctly seating a serviceable sensor when rust or debris has changed its gap
- Replacing a sensor that fails the correct electrical or signal test
- Replacing the specified hub assembly when the sensor/encoder is integrated or the bearing has excessive play
- Correcting tire size, pressure, or severe tread mismatch
- Repairing a brake-fluid leak or other base-brake fault before refilling or bleeding the system
- Calibrating the steering-angle or related stability sensor after the cause is corrected
- Repairing or replacing an ABS hydraulic/control module only after its power, grounds, communication, inputs, and applicable service information are verified
Disconnecting the battery or erasing codes is not a repair. Some lights may temporarily disappear, but the module will detect the same fault again. Unnecessary resets can also erase diagnostic evidence and create additional relearn requirements.
How Can A-Premium Help Once the Failed Part Is Confirmed?
The main buying risk is choosing a part for the right vehicle but the wrong wheel position, connector, cable length, drivetrain, brake package, or sensor design. After diagnosis confirms the repair, A-Premium listings for ABS sensors and wheel hub bearings provide vehicle applications, installation position, product images, connector or ABS configuration, quantity, OE interchange information, and application notes where available.
Enter the complete year, make, model, engine, trim, and drivetrain, then compare the original connector, lead routing, mounting points, stud count, and whether the hub includes an ABS sensor or encoder. If anything is unclear, contact A-Premium customer support with the VIN, diagnostic code, failed wheel position, OE number, and part photos for fitment help before installation. If an eligible unused item is incompatible, A-Premium’s 90-day return policy covers vehicle incompatibility; keep the part, accessories, and packaging complete while the issue is resolved.
FAQs
Will a bad wheel speed sensor turn on both lights?
Yes. ABS, traction control, and stability control often share wheel-speed data. However, scan and test the entire signal path because wiring, the tone ring or encoder, sensor gap, and hub bearing can mimic sensor failure.
Can a weak battery cause the ABS and traction control lights?
Low voltage during starting or a charging-system problem can set module voltage and communication faults. Test the battery, charging output, connections, and stored codes instead of assuming a battery replacement alone will clear the issue.
Why are the lights on after replacing a wheel bearing?
Possible causes include a disconnected or pinched sensor lead, incorrect hub or ABS option, damaged magnetic encoder, excessive gap, incorrect installation, or a code that was not repaired. Compare live wheel speeds and inspect the serviced corner.
Why are the lights on after an alignment?
The steering-angle value may need calibration, the steering wheel may not be centered, or wiring may have been disturbed during related work. Scan the stability/ABS module and compare the steering-angle reading with the actual wheel position.
How do you reset the ABS and traction control lights?
Diagnose and repair the stored fault first. Some systems turn the lights off after a successful self-check and drive cycle; others require code clearing or calibration with a compatible scan tool. A reset without repair is temporary.
