Safety note: Troubleshooting guidance can help you narrow down likely causes, but it cannot replace an in-person inspection. If the vehicle feels unsafe, warning lights are flashing, you smell fuel, see smoke, notice overheating, or have problems with braking, steering, or control, stop driving when it is safe to do so and have the vehicle inspected.
When the ABS light and traction control light come on together, the car is usually telling you that it has lost part of the wheel-speed or stability information those systems rely on. In many vehicles, that means anti-lock braking and traction control are reduced or disabled until the fault is fixed.
The most common causes are a bad wheel speed sensor, a damaged tone ring, wheel bearing play, or a wiring problem near one wheel. Lower system voltage, steering angle sensor issues, and ABS control module faults can also trigger both lights.
The pattern matters. If the lights came on right after brake or hub work, look closely at sensor wiring and installation. If the lights appear with a pulsing brake pedal at low speed, suspect a wheel speed sensor signal problem. If they show up with charging issues or several other warning lights, the fault may be electrical rather than mechanical.
VehicleRuns Quick Diagnosis
ABS Traction Control Lights
Start by noticing when the lights came on and whether the brakes feel normal. The best split is whether this is just a warning-light issue, a low-speed false ABS event, or part of a larger electrical or brake problem.
| What you notice | Most likely cause | What to check first | Urgency |
|---|---|---|---|
| Lights came on, but braking feels normal | Failed wheel speed sensor | Scan ABS codes and inspect the sensor at the flagged wheel | Diagnose soon |
| Lights started after brake or hub work | Damaged sensor or tone ring | Inspect sensor wiring, mounting, and tone ring clearance | Can worsen |
| ABS kicks in at parking lot speeds | Tone ring or sensor signal fault | Check live wheel-speed data during a slow roll | Can worsen |
| Lights with battery or charging problems | Low system voltage | Test battery condition and charging voltage with engine running | Diagnose soon |
| Lights with soft pedal or brake warning | ABS hydraulic or brake fault | Check brake fluid level and stop driving if pedal feels unsafe | Stop driving |
Best first move: Pull ABS fault codes first, then inspect the wheel speed sensor circuit and hub area for the wheel named by the code.
Safety note: If the brake warning light is also on, the pedal feels soft, or the car is acting unstable under braking, do not keep driving until the brake system is checked.
Most Common Causes of ABS and Traction Control Lights
Most cases come down to a few repeat offenders, especially around the wheel-speed sensing system. A fuller list of possible causes and confirmation checks appears later in the article.
- Failed Wheel Speed Sensor: A weak or dead wheel speed sensor is one of the most common reasons the ABS and traction control lights come on together because both systems depend on accurate wheel-speed signals.
- Damaged Tone Ring or Loose Wheel Hub Assembly: A cracked tone ring or wheel bearing with too much play can distort the sensor signal and make the ABS module think one wheel is slipping or stopped.
- Wiring, Connector, or Ground Fault: Corrosion, broken sensor wiring, or a poor ground can interrupt the wheel-speed signal and trigger both warning lights, especially after recent service or in wet conditions.
What ABS and Traction Control Lights Usually Mean
When both lights are on, the vehicle usually still has normal base braking, but the anti-lock and traction-control functions may be unavailable. That means the car may stop normally in dry, straight-line driving, yet lose some control help on slick pavement or during hard braking.
The most useful clue is whether the problem is isolated to one wheel signal or part of a larger electrical issue. A single bad wheel speed reading usually points to a sensor, tone ring, hub, or local wiring problem. Multiple unrelated warning lights, dim electrical behavior, or charging problems push the diagnosis toward battery voltage, grounds, or charging system faults.
Another strong clue is when the lights appear. If they come on immediately after startup and stay on, the module may be seeing a stored hard fault. If they come on only after the car starts moving, the system may not detect the bad signal until it compares wheel speeds. If ABS chatters or the pedal pulses at very low speed on dry pavement, one wheel often has an erratic speed signal.
Recent work matters too. After brake jobs, wheel bearing replacement, axle work, or suspension repair, a sensor wire can be pinched, a tone ring can be damaged, or the sensor gap can be wrong. That pattern is common and worth checking before assuming the ABS module itself has failed.
Possible Causes of ABS and Traction Control Lights
Failed Wheel Speed Sensor
Each wheel speed sensor tells the ABS module how fast that wheel is turning. If one sensor drops out, reads erratically, or goes open-circuit, the module can no longer trust that wheel-speed data and will usually turn on the ABS and traction control warnings together.
Symptoms to Watch For
- ABS and traction lights stay on after startup or soon after driving away
- One wheel shows no or unstable speed data on a scan tool
- Intermittent warning lights in wet weather or after hitting bumps
- Occasional low-speed ABS activation on dry pavement
Moderate Severity
The car may still have normal basic braking, but ABS and traction control assistance are reduced or disabled. That raises risk in slippery or panic-braking conditions.
How to Confirm: Scan the ABS system for stored wheel-speed sensor codes, then look at live wheel-speed data while driving slowly.
Typical fix: Replace the failed wheel speed sensor and repair any damaged mounting hardware or sensor pigtail.
Damaged Tone Ring
The tone ring gives the wheel speed sensor a clean pulse pattern to read. If the ring is cracked, rust-swollen, bent, or packed with debris, the signal can drop out once per wheel revolution and confuse the ABS module, especially at low speed.
Symptoms to Watch For
- ABS activates just before a complete stop
- Lights came on after axle, hub, or brake work
- Visible rust, cracking, or missing teeth on the tone ring
- Problem is worse at low speeds than at highway speed
Moderate to High Severity
A bad tone ring can cause false ABS engagement and longer stops at low speed, not just warning lights. The vehicle should be checked sooner rather than later.
How to Confirm: Inspect the tone ring directly with the wheel removed if accessible, or use a borescope where needed.
Typical fix: Replace the damaged tone ring or the axle or hub assembly that includes it, then clear codes and verify proper sensor reading.
Loose Wheel Hub Assembly
Many vehicles read wheel speed from a sensor mounted next to a hub-based tone ring or bearing encoder. If the wheel bearing develops play, the air gap or encoder signal can change enough to create an intermittent wheel-speed fault.
Symptoms to Watch For
- Growling or humming that changes with road speed
- Play in the wheel when lifted
- ABS and traction lights with steering-related noise
- Fault returns soon after clearing codes
High Severity
A worn hub can affect braking, sensor accuracy, and overall wheel security. It can progress from a warning-light issue to a more serious safety problem.
How to Confirm: Raise the vehicle and check the suspect wheel for bearing play and roughness while spinning it by hand.
How to Diagnose a Bad Wheel Bearing or Hub AssemblyTypical fix: Replace the loose or noisy wheel hub assembly and any integrated wheel-speed sensor components.
How to Replace a Wheel Bearing or Hub AssemblyWiring, Connector, or Electrical Ground Fault
Wheel-speed sensor circuits live in a harsh area near the wheels where road salt, water, movement, and heat can damage wiring. A corroded connector, broken wire, or poor ground can interrupt the signal even when the sensor itself is still good.
Symptoms to Watch For
- Intermittent lights after rain or washing the car
- Fault appears after suspension or brake service
- Visible chafing, stretched wire, or green corrosion at a connector
- ABS code returns for the same corner after sensor replacement
Moderate Severity
The immediate risk is usually loss of ABS and traction-control function rather than total brake failure, but intermittent wiring faults can become harder to track and may worsen over time.
How to Confirm: Use the ABS code location as a guide, then inspect the harness from the body to the wheel for rubbing, pulled pins, or corrosion.
Typical fix: Repair or replace the damaged harness, connector, or ground point and secure the wiring away from moving or sharp components.
Alternator or Charging System Problem
ABS and traction-control systems are sensitive to low or unstable voltage. If charging voltage drops too low or spikes unpredictably, the ABS module may set communication or sensor-related faults and turn on both warning lights even when the wheel hardware is fine.
Symptoms to Watch For
- Battery light or other warning lights on at the same time
- Slow cranking, dim lights, or electrical glitches
- Warnings appear with heavy electrical load
- Multiple unrelated modules store low-voltage codes
Moderate to High Severity
If low voltage is the root cause, the vehicle can become unreliable and may eventually stall or fail to restart. The ABS warning may be only one part of the problem.
How to Confirm: Check battery state of charge first, then measure charging voltage with the engine running and accessories on.
Typical fix: Replace the failing alternator, battery, or related charging-system components and correct any poor power or ground connections.
ABS Hydraulic Control Unit Fault
The ABS hydraulic control unit and module process wheel-speed inputs and command brake-pressure changes. Internal valve problems, pump faults, or module electronics failure can set ABS and traction-control warnings even when the sensors and wiring test normally.
Symptoms to Watch For
- ABS and traction lights remain on with no clear wheel-speed fault
- Pump motor or module-specific ABS codes are stored
- Code returns immediately after clearing
- Problem is not tied to one wheel corner
High Severity
This fault disables core ABS function and can affect brake-pressure control during hard stops. It is less common than sensor issues, but more serious and usually more expensive.
How to Confirm: Scan the ABS module for pump motor, valve, or internal control codes rather than only wheel-speed faults.
How to Diagnose an ABS Hydraulic Control Unit ProblemTypical fix: Replace or rebuild the faulty ABS hydraulic control unit or module, then bleed and initialize the system as required.
Steering Angle Sensor Calibration Fault
Traction and stability systems compare steering input with wheel-speed behavior. If the steering angle sensor is out of calibration after an alignment, battery disconnect, or steering repair, the traction system can flag a fault and sometimes turn on the ABS light as part of the same stability-system warning.
Symptoms to Watch For
- Lights appeared after alignment or steering repair
- No clear wheel-speed sensor fault is found
- Stability-control message appears with the warning lights
- Steering wheel is off-center while driving straight
Moderate Severity
Basic braking is usually still present, but stability and traction functions may not behave correctly. It should be corrected soon, especially if the car has had recent front-end work.
How to Confirm: Use a scan tool that can read steering angle data and check whether the sensor reads centered when the steering wheel is straight.
Typical fix: Recalibrate or replace the steering angle sensor and correct alignment or steering-center issues if needed.
How to Diagnose the Problem
- Confirm whether the ABS light and traction control light are steady or flashing, and note whether any brake, battery, or stability warnings are also on.
- Pay attention to when the lights come on: immediately at startup, only after the car moves, only in wet weather, or after recent brake, hub, axle, or suspension work.
- Check brake fluid level and make sure the pedal feels normal. If the brake warning light is also on or the pedal is soft, treat it as a brake-system problem first.
- Scan the ABS system with a tool that can read chassis codes, not just engine codes. Write down the exact wheel location or module fault before clearing anything.
- Look at live wheel-speed data during a slow drive. A wheel that drops to zero, jumps around, or disagrees with the others gives you a strong starting point.
- Inspect the suspect wheel area for damaged sensor wiring, loose connectors, rust buildup, missing clips, or signs the harness has been stretched or rubbed through.
- If the data points to one corner, inspect the tone ring, encoder, and hub for cracks, rust swelling, debris, or wheel-bearing play.
- If multiple modules show voltage or communication faults, test battery condition, charging voltage, and major ground connections before replacing ABS parts.
- If sensor inputs and power supply test good but ABS-specific internal codes remain, move toward module or hydraulic control unit diagnosis.
- After repairs, clear codes and road test the vehicle to confirm the lights stay off and the wheel-speed signals remain consistent.
Can You Keep Driving With ABS and Traction Control Lights On?
Important: The guidance below is general and cannot confirm that your specific vehicle is safe to drive. If a symptom affects braking, steering, handling, fuel, overheating, smoke, visibility, or vehicle control, treat it as potentially serious and have the vehicle inspected before continued driving when appropriate. For more context, see our Automotive Safety Disclaimer.
Whether you can keep driving depends on whether this is only a disabled-assist warning or part of a larger brake or electrical problem. Many vehicles will still stop normally with the lights on, but they may no longer have anti-lock braking or traction control available when you need them most.
Okay to Keep Driving for Now
Usually reasonable for short-term driving if the ABS and traction lights are on by themselves, the brake pedal feels normal, there is no brake warning light, and the car is otherwise driving normally. Use extra caution on wet, icy, or loose surfaces because ABS and traction intervention may be unavailable.
Maybe Okay for a Very Short Distance
Possibly okay only to get the vehicle home or to a shop if the warnings came on after recent wheel-end work, or if the problem appears limited to low-speed false ABS engagement without other brake issues. Avoid heavy traffic, long trips, and slick conditions until it is diagnosed.
Not Safe to Keep Driving
Do not keep driving if the red brake warning light is also on, the pedal is soft or sinking, the ABS activates unpredictably during normal stopping, the car feels unstable, or the warning lights appear with severe charging problems or repeated stalling. Those patterns suggest a broader safety issue than a simple stored ABS fault.
How to Fix It
The right fix depends on why the system set the warning. On this symptom, the smartest approach is to confirm the bad signal or module fault first, then repair the exact failed part instead of guessing with sensor replacements.
DIY-friendly Checks
Check brake fluid level, inspect visible wheel-speed sensor wiring and connectors, look for obvious hub or tone-ring damage after recent work, and scan for ABS codes if you have the right tool.
Common Shop Fixes
Shops commonly replace failed wheel speed sensors, repair corroded wiring, replace noisy or loose hub assemblies, and recalibrate steering angle sensors after alignment or steering work.
Higher-skill Repairs
ABS hydraulic control unit replacement, advanced circuit testing, module coding, and pressure bleeding procedures usually need professional equipment and a scan tool that can perform ABS functions.
Related Repair Guides
- When to Replace an ABS Wheel Speed Sensor: Mileage and Warning Signs
- ABS Wheel Speed Sensor Repair vs Replacement: Which Is Right?
- How to Test an ABS Wheel Speed Sensor: Wiring and Resistance Checks
- Can You Drive with a Faulty ABS Wheel Speed Sensor?
- ABS Wheel Speed Sensor Location: Where to Look on Different Vehicles
Typical Repair Costs
Repair cost depends on the vehicle, labor rates, and the exact fault found. The ranges below are typical U.S. parts-and-labor estimates, not make-specific quotes.
Wheel Speed Sensor Replacement
Typical cost: $150 to $350
This usually applies when one sensor has failed electrically or is physically damaged at a single wheel.
Wheel Speed Sensor Wiring Repair
Typical cost: $120 to $350
Cost depends on whether the fix is a simple connector repair or a longer harness repair near the suspension.
Wheel Hub Assembly Replacement
Typical cost: $300 to $700
This is common when bearing play or an integrated encoder ring is causing the ABS fault.
Alternator or Charging System Repair
Typical cost: $250 to $800
Price varies widely with engine layout, alternator output, and whether the battery or cables also need attention.
Steering Angle Sensor Calibration or Replacement
Typical cost: $120 to $600
A simple recalibration is much cheaper than replacing the sensor or related steering components.
ABS Module or Hydraulic Control Unit Replacement
Typical cost: $700 to $1,800+
This higher range reflects the part cost, programming or initialization, and possible ABS bleeding procedures.
What Affects Cost?
- Whether the problem is a simple sensor fault or a hub or module failure
- Vehicle design and how accessible the sensor, hub, or ABS unit is
- OEM versus aftermarket parts quality and availability
- Local labor rates and whether programming or ABS bleeding is required
- Rust, corrosion, or previous damage around the wheel-end harness
Cost Takeaway
If the lights came on by themselves and the brakes feel normal, the repair often lands in the lower to middle cost range, especially for a sensor or wiring fault. Costs climb when the fault involves a hub assembly, charging-system problem, or ABS control unit, or when several warning lights point to a larger electrical issue.
Symptoms That Can Look Similar
- ABS Light Comes On After Wheel Bearing Replacement: What It Means and What to Do Next
- ABS Light Comes On Only After Driving a Few Miles: What It Means and What to Do Next
- ABS Light and Traction Control Light With Wheel Noise: When to Stop Driving and What to Check
- ABS Light On and Speedometer Not Working: What It Means and What to Do Next
- ABS Light On and ABS Activates at Low Speed: What It Means and What to Do Next
Parts and Tools
- ABS Wheel Speed Sensors
- Wheel Hub Assemblies
- Brake Fluid
- Car Batteries
- Alternators
- OBD-II Scanner
- Digital Multimeter
FAQ
Can ABS and Traction Control Lights Come on From a Bad Wheel Bearing?
Yes. A loose or failing wheel bearing can affect the sensor air gap or the encoder signal inside the hub, which can make the ABS module think one wheel is reading incorrectly.
Will My Brakes Still Work if the ABS and Traction Lights Are On?
Usually yes, the basic hydraulic brakes still work. What you may lose is anti-lock braking, traction control, and sometimes part of the stability-control system, so stopping and control on slick surfaces can be worse.
Can Low Battery Voltage Trigger ABS and Traction Control Lights?
Yes. Low or unstable system voltage can confuse the ABS module and other control modules, especially during startup or while driving with a weak alternator or battery.
Why Did the Lights Come on Right After a Brake Job or Wheel Bearing Replacement?
That often points to a disturbed wheel-speed sensor, damaged wiring, incorrect sensor gap, or a tone ring issue. Recent service is a strong clue because the fault may be at the exact corner that was worked on.
Do I Need an ABS-capable Scan Tool to Diagnose This Properly?
In most cases, yes. A basic code reader may miss chassis and ABS codes, while an ABS-capable scanner can show the exact fault and live wheel-speed data that make diagnosis much faster.
Final Thoughts
When ABS and traction control lights come on together, start with the most common path: pull the ABS codes, identify the affected wheel or system, and inspect the sensor, wiring, and hub area before assuming the module has failed. That simple order prevents a lot of unnecessary parts swapping.
The seriousness depends on whether you are dealing with a lost driver-assist function, a false ABS event, or a larger brake or charging-system problem. If braking feels normal, you usually have time to diagnose carefully. If the pedal feels wrong or other brake warnings are present, treat it as a safety issue first.