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 check engine light and traction control light come on together, the two warnings are often related even if they seem like separate systems. In many vehicles, the traction control system depends on clean engine data and predictable torque control, so an engine or sensor fault can trigger the check engine light and cause traction control to reduce function or shut off.
That means the problem is often not the traction control system itself. A misfire, throttle-body fault, wheel speed sensor problem, or wiring issue can cause the engine computer to set a fault and the stability or traction system to respond.
The most useful clues are what the vehicle does besides showing the lights. Rough running, reduced power, slipping shifts, ABS warnings, or a no-change driving feel all point in different directions. Some causes are minor enough to diagnose soon, while others can mean limp mode, poor acceleration, or unsafe handling on slick roads.
VehicleRuns Quick Diagnosis
Check Engine and Traction Control Lights Together
Start with what the vehicle is doing besides showing the lights. If it runs rough or has reduced power, look at engine faults first. If it drives normally but has ABS-related warnings too, focus more on wheel-speed or control-system faults.
| What you notice | Most likely cause | What to check first | Urgency |
|---|---|---|---|
| Rough idle, stumble, or flashing check engine light | Engine misfire | Scan for misfire codes and inspect plugs and coils | Stop driving |
| Reduced power after lights come on | Limp mode fault | Read stored codes before clearing anything | Can worsen |
| Both lights on, car otherwise drives normally | Sensor or control fault | Scan engine and ABS modules for related codes | Diagnose soon |
| ABS light also on or speedometer acts odd | Wheel speed sensor fault | Inspect wheel speed sensor wiring and tone rings | Can worsen |
| Light came on after fueling or loose cap | EVAP fault | Tighten gas cap and scan for EVAP codes | Diagnose soon |
Best first move: The smartest starting point is a full code scan, because the engine computer and traction or ABS system often store linked faults that explain why both lights appeared together.
Safety note: Do not keep driving if the check engine light is flashing, the engine is misfiring badly, power is sharply reduced, or the vehicle feels unstable. You can damage the catalytic converter or lose traction-control assistance when you need it most.
Most Common Reasons the Check Engine and Traction Control Lights Come On Together
The most common reasons both lights come on together are listed below. A fuller list of possible causes and how to narrow them down appears later in the article.
- Engine Misfire: A misfire is one of the most common triggers because the engine computer sees unstable combustion and the traction system may disable torque-management functions.
- Wheel Speed Sensor Fault: A bad wheel speed signal can affect traction control directly, and on some vehicles it can also lead to related engine or stability warnings.
- Engine Management or Limp Mode Fault: Throttle, airflow, or other engine-control problems can put the vehicle in reduced-power mode and turn on the traction control light at the same time.
What It Usually Means When Both Lights Come On
When these two lights appear together, the vehicle is often telling you that one fault is affecting more than one system. Modern traction control does not work in isolation. It relies on the engine computer, throttle control, wheel speed data, and sometimes transmission data to manage wheel slip safely.
If the engine is running rough, hesitating, or down on power, think engine fault first. Misfires, throttle-body issues, airflow sensor problems, and other fuel or ignition faults can make the computer turn on the check engine light and suspend traction control because torque output is no longer predictable.
If the vehicle drives fairly normally but the traction control light is on steadily, especially with an ABS light or odd speed signal, think wheel speed sensor, tone ring, or chassis-side electrical fault. In that version, the traction system may be missing accurate wheel-speed data and disabling itself as a precaution.
The pattern matters. A flashing check engine light points to an active misfire and a higher-risk condition. A steady check engine light with no obvious drivability problem is often less urgent, though still worth scanning soon. Reduced power, harsh shifting, or limp mode pushes the diagnosis toward a broader engine-management or electronic throttle problem.
Possible Causes of the Check Engine and Traction Control Lights Coming On Together
Engine Misfire
When one or more cylinders misfire, the engine computer detects unstable combustion and turns on the check engine light. Many traction control systems then limit or disable intervention because engine torque is no longer being delivered smoothly or predictably.
Symptoms to Watch For
- Rough idle or shaking under load
- Flashing check engine light
- Poor acceleration or hesitation
- Raw fuel smell from the exhaust
High Severity
An active misfire can quickly overheat and damage the catalytic converter, and drivability can worsen without much warning.
How to Confirm: Scan for stored and pending misfire codes such as P0300 or a single-cylinder P030X code.
Typical fix: Replace the failed ignition component, repair the fuel or air-fuel issue causing the misfire, and clear the codes after the engine runs smoothly.
Wheel Speed Sensor Fault
Traction control depends on accurate wheel-speed input from all four corners. If one sensor drops out or reads erratically, the traction system may shut down, and some vehicles also set related powertrain or communication faults that bring on the check engine light.
Symptoms to Watch For
- ABS light on with the traction light
- Traction control activates oddly
- Speedometer or stability system acts inconsistently
- Problem appears after brake or hub work
Moderate Severity
The car may still drive normally on dry pavement, but traction and stability functions may be reduced when road grip is poor.
How to Confirm: Scan the ABS or stability module, not just the engine computer.
Typical fix: Replace the failed wheel speed sensor or damaged hub-related tone ring, and repair any corroded or broken wiring at that corner.
Engine Management or Limp Mode Fault
A broader engine-control problem can force the vehicle into reduced-power mode. When that happens, traction control may also be disabled because the system cannot manage engine torque normally.
Symptoms to Watch For
- Reduced power or limited throttle response
- Vehicle will not accelerate normally
- Possible transmission shift changes
- Warning message for reduced engine power
Moderate to High Severity
Some limp mode events are protective and may let you drive slowly, but the root cause can still be serious and may leave you with little power in traffic.
How to Confirm: Use a scan tool to read all stored powertrain codes and look at throttle, airflow, and torque-related data.
How to Diagnose Limp ModeTypical fix: Repair the specific engine-control fault, such as the throttle body, actuator, sensor, or related module issue, and perform any required relearn.
Dirty or Faulty Mass Air Flow Sensor
A bad MAF signal can skew fuel delivery and engine load calculations. That can trigger the check engine light, cause hesitation or reduced power, and interfere with the torque information the traction system needs.
Symptoms to Watch For
- Hesitation during acceleration
- Rough idle or stalling tendency
- Poor fuel economy
- Codes related to airflow or fuel trim
Moderate Severity
The vehicle may remain drivable, but poor fuel control can lead to worsening performance and secondary catalyst stress over time.
How to Confirm: Scan for airflow and fuel-trim codes, then compare live MAF readings against engine speed and load.
How to Diagnose a Dirty or Faulty Mass Air Flow SensorTypical fix: Clean the sensor if contamination is the issue or replace the MAF sensor if the signal remains faulty.
EVAP System Leak or Purge/Vent Valve Fault
An EVAP fault commonly turns on the check engine light, and some vehicles also switch on the traction control light whenever the powertrain computer stores certain emissions-related faults. The car may still seem to drive normally.
Symptoms to Watch For
- Light appeared after fueling
- Loose or worn gas cap
- No major drivability change
- EVAP-related codes like small leak or purge fault
Low Severity
This type of fault usually does not create an immediate safety issue, but the warning should still be resolved so new faults are not masked.
How to Confirm: Scan for EVAP codes such as leak, purge flow, or vent control faults.
Typical fix: Replace the faulty gas cap, purge valve, vent valve, or leaking EVAP hose or component.
Wiring, Connector, or Electrical Ground Fault
Shared grounds, damaged harness sections, or corroded connectors can create faults in more than one module at the same time. That makes this a realistic cause when the lights appear together with inconsistent behavior or multiple unrelated codes.
Symptoms to Watch For
- Intermittent lights that come and go
- Problem after heavy rain or recent repairs
- Multiple unrelated codes
- Sensor readings that drop out suddenly
Moderate Severity
Electrical faults can be intermittent and hard to predict, and they can disable driver-assist features without warning.
How to Confirm: Inspect the harness and connectors around affected sensors, wheel ends, battery grounds, and engine grounds.
Typical fix: Repair damaged wiring, clean or replace corroded connectors, and restore proper ground and power supply integrity.
How to Diagnose the Problem
- Note whether the check engine light is steady or flashing, and whether the car runs normally, hesitates, or has reduced power.
- Check for other warnings at the same time, especially ABS, stability control, or reduced engine power messages.
- Scan for diagnostic trouble codes in both the engine computer and the ABS or traction control module. Do not rely on a basic code reader if it only reads powertrain codes.
- Write the codes down before clearing anything. The code combination often shows whether the engine fault caused the traction light or the traction-side fault came first.
- If the engine runs rough, inspect the obvious misfire items first, including spark plugs, ignition coils, and any loose intake plumbing.
- If the vehicle drives normally but traction-related warnings are present, inspect wheel speed sensor wiring, tone rings, and recent brake or hub work.
- Look at live data when possible. Misfire counters, throttle position, MAF readings, and wheel-speed values can quickly narrow the real cause.
- Check for simple triggers such as a loose gas cap, disconnected sensor connector, weak battery voltage, or recent repairs that may have disturbed wiring.
- If the vehicle is in limp mode or has multiple communication or electrical codes, move to a deeper electrical diagnosis instead of replacing parts by guesswork.
- After the repair, clear codes and confirm with a road test that both the check engine and traction control lights stay off.
Can You Keep Driving With the Check Engine 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 less on the lights themselves and more on what the car is doing. Sometimes both lights come on from a minor emissions fault. Other times they come on because the engine is misfiring, power is limited, or traction control has been disabled.
Okay to Keep Driving for Now
This usually applies when the check engine light is steady, the car drives normally, there is no flashing light, and no major ABS or stability warning is present. You should still scan it soon, because traction control may be reduced and a minor fault can hide later problems.
Maybe Okay for a Very Short Distance
A short drive to home or a repair shop may be reasonable if the car has mild hesitation, a steady check engine light, or limited traction-control function but still feels stable and predictable. Avoid hard acceleration, rain, snow, and highway merging if power feels reduced.
Not Safe to Keep Driving
Do not keep driving if the check engine light is flashing, the engine is shaking badly, power drops sharply, the vehicle enters limp mode, or the car feels unstable. Also stop if ABS and traction warnings are combined with braking or control issues.
How to Fix It
The right fix depends on the fault that turned both lights on. In many cases the traction control light is reacting to another problem, so the repair starts with finding the root engine, sensor, or electrical issue instead of treating the traction light by itself.
DIY-friendly Checks
Start with a full code scan if you have access to one, then check the gas cap, battery voltage, visible wiring, intake hose connections, and obvious misfire items like worn spark plugs or a loose coil connector.
Common Shop Fixes
Common repair-shop fixes include replacing ignition coils or spark plugs, cleaning or replacing a MAF sensor, replacing a wheel speed sensor, or repairing damaged sensor wiring and connectors.
Higher-skill Repairs
Reduced-power faults, throttle-body failures, module communication issues, and intermittent harness or ground problems usually need better scan tools, live-data analysis, and sometimes module relearn or circuit-level electrical testing.
Related Repair Guides
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- Ignition Coil Repair vs Replacement: What’s the Better Option?
- How to Choose the Right Ignition Coil for Your Car
- Can You Drive with a Bad Ignition Coil?
- Single vs Coil Pack vs Coil-on-Plug: What’s the Difference?
Typical Repair Costs
Repair cost depends on the vehicle, local labor rates, and the exact fault that linked the two warnings. The ranges below are typical U.S. parts-and-labor estimates, not exact quotes for every make or model.
Spark Plug or Ignition Coil Repair
Typical cost: $120 to $600
This range covers anything from a simple single-cylinder ignition fix to multiple coils and plugs on harder-to-access engines.
Wheel Speed Sensor Replacement
Typical cost: $150 to $350
Cost usually depends on which wheel is affected and whether rust, seized hardware, or harness damage adds labor.
Mass Air Flow Sensor Cleaning or Replacement
Typical cost: $80 to $350
A simple cleaning is inexpensive, but replacement cost rises if the sensor is integrated into a larger housing.
EVAP Purge Valve, Gas Cap, or Leak Repair
Typical cost: $40 to $300
A gas cap is cheap, while purge-valve or smoke-test-based EVAP repairs land higher in the range.
Throttle Body or Reduced-power Repair
Typical cost: $250 to $900
This often applies when the vehicle enters limp mode and needs throttle-body replacement, relearn, or related circuit repair.
Wiring or Ground Repair
Typical cost: $120 to $800+
Minor connector repairs are relatively affordable, but intermittent harness tracing and multi-circuit faults can take much more labor.
What Affects Cost?
- Whether the problem is a simple sensor fault or a deeper drivability issue
- Labor access around plugs, coils, sensors, or wiring harnesses
- Need for ABS-capable or factory-level diagnostic equipment
- OEM versus aftermarket parts choice
- Whether multiple codes are symptoms of one root cause or several separate faults
Cost Takeaway
If the vehicle runs normally and the code points to EVAP or a single sensor issue, repair cost is often on the lower end. Rough running, limp mode, or intermittent electrical faults usually push the job into the mid or upper cost tier because diagnosis time matters as much as parts.
Symptoms That Can Look Similar
- Subaru Check Engine Light With Flashing Cruise Control: What It Means and What to Do Next
- Engine Surges At Low Speed: Common Causes and What to Check
- Car Jerks At Low Speed: Common Causes and What to Check
- Car Surges Forward at Low Speed: Common Causes and What to Check
- Car Shakes While Driving and Check Engine Light Is on: What It Means and What to Do Next
Parts and Tools
FAQ
Why Would the Traction Control Light Come on with the Check Engine Light?
On many vehicles, traction control depends on accurate engine torque data and stable engine operation. If the engine computer detects a misfire, throttle fault, or other control problem, it may turn on the check engine light and disable traction control at the same time.
Can a Bad Wheel Speed Sensor Cause the Check Engine Light Too?
It can on some vehicles, especially when the fault affects shared control systems or triggers related communication codes. More often, a wheel speed sensor turns on ABS and traction warnings first, but the only way to know is to scan all modules.
Is It Safe to Drive if Both Lights Are on but the Car Feels Normal?
It may be safe for a short time if the check engine light is steady and there are no drivability problems, but you should still diagnose it soon. Traction control may not be available when road conditions get slippery.
Should I Clear the Codes and See if They Come Back?
Write the codes down first. Clearing them too early can erase useful freeze-frame and module data that helps show whether the engine fault caused the traction warning or the other way around.
Could a Loose Gas Cap Turn on Both Lights?
Yes, on some vehicles a simple EVAP fault from a loose or failing gas cap can trigger the check engine light and also switch on the traction control light. If the car otherwise drives normally, that is one of the easier things to rule out.
Final Thoughts
When the check engine light and traction control light come on together, start by deciding whether the car has a real drivability problem or just a warning. Rough running, flashing check engine behavior, or reduced power usually points to an engine-side fault first. Normal driving with extra ABS or stability warnings leans more toward a sensor or chassis-side issue.
The best next step is a full scan of both powertrain and ABS or traction modules, followed by the most likely checks for the code pattern you find. Starting with the real root cause is what gets both lights to stay off.