If both dashboard warnings illuminate, your vehicle is telling you it has safety or performance issues that need attention.
Sometimes the cause is minor, like a loose gas cap or temporary slip on a wet road. Other times it points to misfires, sensor faults, ABS wiring problems, or weak charging output that affect drivability and emissions.
A flashing engine warning means a misfire or severe fault. Slow down, avoid hard acceleration, and seek professional evaluation quickly to avoid engine or catalytic converter damage.
Modern vehicle computers link chassis and powertrain systems, so one failing sensor can trigger both indicators. Many U.S. auto parts stores offer free OBD-II scans to pull trouble codes before you book service.
This article will explain what each light means, list frequent triggers, show safe curbside checks, and outline fixes plus when to call a shop. A simple checklist helps separate urgent repairs from minor issues and saves time and money.
Key Takeaways
- Dual warnings can signal either minor faults or serious faults affecting safety.
- Flashing engine alert requires immediate reduced speed and quick inspection.
- One sensor can cause multiple warnings due to linked vehicle systems.
- Free OBD-II scans at parts stores can reveal diagnostic codes fast.
- Follow a step-by-step checklist to spot urgent problems before a shop visit.
What Your Check Engine Light and Traction Control Light Mean Right Now
If both dashboard warnings appear, your vehicle’s computers are flagging a problem that can affect safety, performance, or emissions.
The traction control system prevents wheel spin and helps keep the vehicle stable. Its indicator can mean the system is actively intervening, has been turned off by the driver, or has logged a fault.
The engine light signals that the engine management system detected an issue. That ranges from a minor evaporative leak to sensor failures or a dangerous misfire.
Many models share sensors between the anti-lock braking system and traction systems. A single wheel-speed sensor or wiring fault in the braking system can illuminate several lights at once.
Temporary flickers during rain, ice, or gravel often show normal traction intervention. A steady or flashing engine alert is different: a flashing indicator usually points to misfire and needs immediate attention.
- What you may feel: reduced power, harsher shifts, or stability intervention.
- What to do now: slow down, avoid hard inputs, and read any companion dashboard messages like “TCS Off” or ABS warnings.
Check Engine Light and Traction Control Light: Common Causes & How to fixes
When both warnings appear together, they usually point at a shared sensor, voltage problem, or a wheel-related issue that affects stability and emissions.
TC system turned off or disabled
Drivers can switch traction control off during some maneuvers. A module fault can also disable the feature and trigger the traction control light, reducing stability on slick roads.
Faulty wheel speed sensors
Damaged sensors or frayed wiring at the hubs break data flow. That can set multiple warnings if control modules detect inconsistent wheel data.
Temporary loss of traction
Rain, ice, or snow often activate TCS briefly. If a warning stays on after conditions clear, inspect sensors and tire pressures.
ABS malfunctions
Anti-lock braking faults share sensors with traction systems. A braking system error may disable traction functions and illuminate both lights.
Engine misfires and ignition faults
Bad coils or worn plugs cause misfires and a flashing engine light. You may notice rough running or reduced power that needs quick attention.
Air/fuel sensor problems
A failing MAF or throttle position sensor upsets fuel metering and can set codes that affect drivability and torque control.
EVAP leaks or loose gas cap
A loose cap or EVAP leak often triggers engine codes. These are easy checks that can save a trip to the shop.
Tire pressure and size
Low pressure, uneven wear, or mismatched sizes distort wheel speed readings and can confuse stability systems.
Low voltage issues
Weak batteries or failing alternators cause modules to act erratically. Low system voltage may set several warnings at once.
Tip: Log recent tire, brake, or battery service—this info often speeds diagnostic work and pinpoints the probable cause.
How to Diagnose the Problem Safely and Efficiently (Present)
If dashboard warnings appear together while driving, begin with a calm, safety-first response. Reduce speed, avoid heavy throttle, and note whether the engine light is steady or flashing. A flashing alert implies urgent misfire risk—slow down and head for diagnosis.
Quick roadside checks
Confirm the gas cap is tight and verify tire pressures. Low tires or a loose cap often trigger codes that clear once corrected.
Visually scan wheel hubs and nearby wiring for damaged sensors or disconnected harnesses. A torn wheel-speed sensor lead can light multiple systems at once.
Read codes before replacing parts
Use an OBD-II scanner, or get a free code read at an auto parts store. Retrieve diagnostic trouble codes and map them to likely areas—misfire, MAF/throttle sensors, EVAP leaks, or ABS wheel-speed faults.
- Prioritize: companion dashboard warnings (ABS, TPMS) help narrow which control system is affected.
- Document: when and where the lights came on—road surface, speed, and load—to help replicate intermittent trouble.
- Avoid: disconnecting the battery to clear lights; it erases freeze-frame data technicians need.
If drivability is poor or the engine light flashes, keep speeds low and go straight to professional diagnosis rather than continuing down the road.
Practical Fixes, When to See a Mechanic, and Prevention Tips
Tackle simple items first to rule out easy problems before a repair visit. These actions are safe, low-cost, and often restore normal dashboard readings.
Quick fixes you can do now
Reseat the gas cap until it clicks. A loose cap often sets a code and clears after a drive cycle.
Clear debris from wheel hubs and sensor areas. Mud and salt block signals for the ABS and traction systems.
Check visible connectors and push them fully home. A loose plug can mimic a faulty sensor.
When to stop driving and tow
Stop immediately if the check engine light is flashing, you feel a strong misfire, or brake/ABS warnings appear. Driving can cause severe damage to the catalytic converter and braking system.
Arrange a tow and professional diagnosis rather than risking further harm.
Preventive maintenance
- Verify tire pressures monthly and keep sizes matched to protect wheel speed readings.
- Inspect sensors and wiring in salty or muddy climates; clean when needed.
- Load-test the battery and check alternator output yearly to avoid low-voltage faults.
- Schedule software updates and diagnostics at service intervals; many issues are fixed by modern calibrations.
Conclusion
When two warning indicators glow at once, act quickly to protect drivability and safety. Brief traction events in poor conditions can be normal, but steady or flashing engine signals demand action. Slow your speed and note road conditions before checking simple items like the gas cap and tire pressures.
Use an OBD-II scan to turn codes into a clear repair plan rather than guessing. Many issues trace to a faulty wheel speed sensor, ABS/TCS interaction, misfire, weak battery, or a loose cap. Securing connectors or clearing debris often restores normal lights the same day.
Document when the lights came on, the surface and speed, then schedule diagnostics if the warnings persist. Prompt, informed steps save time, reduce repair cost, and keep your vehicle safe on the road.
FAQ
What does it mean when both the check engine and traction control lights illuminate?
When both bulbs come on, the engine management system has detected a fault and the traction control system may be disabled or limited. Common causes include shared wheel speed sensor signals, ABS module errors, ignition misfires, or electrical issues such as a weak battery or poor grounds. The dashboard warning indicates you should assess drivability and read diagnostic trouble codes (DTCs) as soon as possible.
Can a loose gas cap trigger the engine warning while the traction control light stays off?
Yes. A loose or damaged gas cap can cause an EVAP system fault that sets an engine code and illuminates the engine warning. That alone usually won’t affect traction control unless the vehicle also has unrelated ABS or wheel sensor faults. Tightening or replacing the cap often clears the issue after a few drive cycles or a code clear with an OBD-II scanner.
Why would a faulty wheel speed sensor cause both indicators to light?
Wheel speed sensors feed data to ABS and traction control modules. If a sensor fails or its wiring is damaged, the ABS may report an error that disables traction control while the engine computer might also log related faults. Replacing the sensor or repairing wiring typically restores normal operation.
Could bad tires or uneven tire pressure trigger traction warnings?
Yes. Low pressure, mismatched tire sizes, or extreme uneven wear can confuse wheel speed readings and activate the traction control warning. Check and inflate tires to recommended pressures, rotate or replace tires as needed, and recheck the lights.
What does a flashing engine light mean versus a steady light?
A flashing engine warning usually signals a serious problem, often an active misfire that can damage the catalytic converter. You should reduce speed and have the vehicle inspected immediately. A steady light indicates a less urgent fault that still needs diagnosis but may allow limited driving until repaired.
How can I read the diagnostic trouble codes myself?
Use an OBD-II scanner plugged into the vehicle’s diagnostic port to retrieve DTCs. Many auto parts stores offer free code reads. Once you have codes, research manufacturer-specific meanings or share them with a qualified technician to determine whether the fault lies with the engine, ABS, or traction control systems.
Are alternator or battery problems able to cause these dashboard warnings?
Yes. Low voltage from a weak battery or failing alternator can create erratic sensor readings and module faults that trigger both warnings. Test battery state of charge and alternator output; replace faulty components and clear codes to see if warnings return.
When should I stop driving and arrange a tow?
Stop driving and tow if the engine light is flashing, you experience severe misfires, a loss of braking performance, ABS/traction failure with unstable handling, or other unsafe symptoms. For non-urgent steady lights, drive cautiously to a repair shop after retrieving diagnostic codes.
What quick checks can I do at home before visiting a mechanic?
Inspect tire pressures and condition, tighten or replace the gas cap, look for obvious wiring damage near the wheels, and ensure battery terminals are clean and tight. These simple steps can resolve common faults or at least narrow down the issue before professional diagnosis.
How do ABS faults interact with the traction control system?
ABS and traction control share sensors and control modules. An ABS malfunction often disables traction control because the system depends on accurate wheel speed data and proper module function. Repairing the ABS fault—sensors, modulators, or wiring—usually restores traction control.
Can software updates or module resets fix these warnings?
Sometimes. Manufacturers release control module updates that address sensor algorithms or fault logic. A dealer or qualified shop can check for technical service bulletins and perform software updates or targeted resets after repairs to prevent recurring warnings.
How much do typical repairs cost for the most common faults?
Costs vary by vehicle and fault. Replacing a wheel speed sensor often ranges from a modest parts-and-labor fee, while ABS module replacement or catalytic converter repairs cost more. Battery or gas cap fixes are inexpensive. Get diagnostic codes first to estimate accurate repair costs from a trusted shop.
Is it safe to clear the codes with an OBD-II tool to turn off the lights?
Clearing codes will extinguish warnings temporarily, but it does not fix the root cause. If the underlying fault remains, the light will return. Use code clearing after repairs or to confirm an intermittent issue, and only drive confidently once the problem is resolved.
Could environmental conditions like rain or snow trigger the traction warning?
Yes. Temporary loss of traction from wet, icy, or snowy roads can activate the traction system and illuminate the warning. The light typically resets when traction returns, but persistent illumination suggests a sensor or system fault needing attention.
