Traction control light and check engine light blinking indicate a potentially serious issue requiring immediate attention. When both warning lights appear simultaneously—especially with a blinking check engine light—it typically signals an active engine misfire that could damage your catalytic converter and compromise vehicle stability. You should pull over safely, avoid driving further, and have your vehicle professionally diagnosed to prevent expensive damage.
Dashboard Warning Lights
Dashboard warning lights serve as your vehicle’s communication system, alerting you to potential problems before they escalate into major failures. When multiple warning lights illuminate simultaneously, it’s particularly important to understand what your vehicle is trying to tell you.
Check Engine Light (CEL)
The check engine light, also known as the malfunction indicator lamp (MIL), is connected to your vehicle’s electronic control unit (ECU)—essentially your car’s brain. This sophisticated computer constantly monitors various engine and emissions systems through an extensive network of sensors.
The check engine light can appear in two distinct ways:
- Solid illumination: Indicates a problem that requires attention soon but isn’t immediately threatening to your engine
- Blinking/flashing: Signals a severe problem occurring in real-time that requires immediate attention
A blinking check engine light specifically indicates that your engine is misfiring severely enough that unburned fuel is entering the exhaust system. This can quickly damage your catalytic converter—an expensive component that can cost between $1,000-$3,000 to replace, depending on your vehicle model.
Traction Control Light
The traction control light typically appears as a car with skid marks or may be labeled “TRAC,” “TCS,” or “ESC” (Electronic Stability Control). This system helps maintain vehicle stability by detecting and preventing wheel slip.
The traction control light can illuminate for several reasons:
- When the system is actively working to prevent wheel slip (temporary flashing)
- When the system has been manually disabled
- When there’s a malfunction in the system
- When the system has been automatically disabled due to another vehicle issue
Why Both Lights Appear Together
According to recent research and manufacturer documentation, there’s a specific relationship between these two warning lights. In many modern vehicles, particularly Toyota models as noted, the traction control system automatically turns off when the check engine light is on.
This is a programmed safety feature because:
- Engine performance issues can affect the traction control system’s ability to function properly
- The vehicle’s computer prioritizes addressing engine problems before maintaining enhanced stability features
- Some sensor malfunctions can affect both systems simultaneously
Common Causes of Blinking Check Engine Light and Traction Control Light
Here are the common causes of blinking check engine light and traction control light:
1. Severe Engine Misfire
The most common and serious cause of a blinking check engine light is a severe engine misfire. This is particularly concerning as it means fuel isn’t burning properly in one or more cylinders. Common causes include:
- Worn or fouled spark plugs
- Faulty ignition coils or spark plug wires
- Clogged fuel injectors
- Vacuum leaks
- Low fuel pressure
- Timing issues
In the case of a Reddit user mentioned in the search results, a mechanic diagnosed multiple issues stemming from overheating: failed cooling fans, a leaking thermostat housing, a failed water pump, and oil-filled spark plug tubes due to a failed valve cover gasket—resulting in an $1,800 repair bill.
2. Wheel Speed Sensor Problems
Faulty wheel speed sensors are another common culprit. These sensors monitor the rotational speed of each wheel and provide crucial data to both the traction control system and the engine management system. When they malfunction due to dirt, damage, or electrical issues, they can trigger both warning lights.
3. ABS System Malfunctions
Since the traction control system typically works in conjunction with the Anti-lock Braking System (ABS), problems with the ABS can affect both systems and trigger multiple warning lights. Common ABS issues include:
- Faulty ABS modules
- Damaged tone rings
- Wiring problems
- Low brake fluid
4. Bad Fuel or Incorrect Fuel Type
As noted in the search results, using incorrect fuel (such as 87-octane in a vehicle that requires 91-octane) can trigger the check engine light. In some cases, this can also affect the traction control system if the engine performs poorly enough.
5. Overheating Issues
Engine overheating can cause multiple systems to fail simultaneously. As seen in the Reddit user’s case, overheating led to a cascade of failures that triggered both warning lights.
Is It Safe to Drive With These Warning Lights?
When both the traction control light and a blinking check engine light appear:
Stop Driving Immediately If:
- The check engine light is blinking/flashing
- You notice unusual engine sounds, vibrations, or performance issues
- The vehicle is overheating
- You smell unusual odors (particularly a sulfur/rotten egg smell)
According to Desert Toyota, “A severe engine issue is occurring in real-time. This typically involves misfires, but in any case, pull over immediately and get your car towed to a service center; engine catastrophe may soon occur otherwise.”
Limited Driving May Be Possible If:
- The check engine light is solid (not blinking)
- The traction control light is the only additional warning light
- The vehicle is operating normally without unusual symptoms
Even in these cases, you should limit driving to reaching a nearby service facility.
How to Diagnose the Problem
Using an OBD-II Scanner
The most effective first step in diagnosis is to retrieve the error codes stored in your vehicle’s computer using an OBD-II scanner. As mentioned in the search results, this is relatively easy to do:
- Locate the OBD-II port (typically under the driver’s side dashboard)
- Connect an OBD-II scanner
- Turn the ignition on
- Follow the scanner’s instructions to read the codes
Common codes you might encounter include:
- P0300-P0308: Cylinder misfire detected (specific cylinder or random/multiple cylinders)
- P0171-P0175: Fuel system too lean/rich
- C0035-C0050: Wheel speed sensor circuit malfunction
- U0123: Communication with traction control module lost
Many auto parts stores offer free code reading services if you don’t have your own scanner.
Professional Diagnosis
While code reading provides valuable information, a professional diagnosis is often necessary to identify the root cause. Professional technicians can perform:
- Comprehensive system scans beyond basic code reading
- Visual inspections of components
- Specialized testing of ignition components
- Fuel pressure testing
- Compression testing
- Sensor voltage testing
Solutions for Blinking Check Engine Light and Traction Control Light
The appropriate solution depends entirely on the underlying cause:
For Misfire-Related Issues
- Replace spark plugs and ignition coils
- Clean or replace fuel injectors
- Repair vacuum leaks
- Replace damaged wiring
- Address fuel delivery issues
- Fix cooling system problems (as in the Reddit user’s case)
For Sensor-Related Issues
- Clean or replace wheel speed sensors
- Repair damaged wiring or connectors
- Replace faulty ABS components
- Reset the vehicle’s computer after repairs
For Fuel-Related Issues
- Drain and replace fuel if incorrect fuel was used
- Clean fuel system if contaminated fuel is suspected
- Replace fuel filter if clogged
Preventive Maintenance to Avoid These Warning Lights
To reduce the likelihood of experiencing these warning lights:
- Follow your vehicle’s maintenance schedule for regular service intervals
- Replace spark plugs according to manufacturer recommendations
- Keep your engine properly tuned
- Use the correct grade of fuel as specified in your owner’s manual
- Maintain proper cooling system function with regular coolant flushes
- Address minor issues promptly before they develop into major problems
Cost Considerations
Repair costs can vary significantly depending on the underlying issue:
- Spark plug replacement: $100-$400 depending on engine design
- Ignition coil replacement: $150-$600 depending on how many need replacement
- Wheel speed sensor replacement: $200-$400 per sensor
- Catalytic converter replacement: $1,000-$3,000
- Major engine repairs: $1,500-$5,000+
As seen in the Reddit user’s case, multiple related issues resulted in an $1,800 repair bill. Addressing problems promptly can often prevent this kind of cascade failure that leads to more expensive repairs.
When to Seek Professional Help
You should seek professional help immediately if:
- The check engine light is blinking
- Both warning lights appear simultaneously
- The vehicle is operating abnormally
- You notice unusual sounds, smells, or performance issues
Even if you’re mechanically inclined, modern vehicles have complex, interconnected systems that often require specialized diagnostic equipment to properly troubleshoot.
Conclusion
When both traction control light and check engine light appear—especially if the check engine light is blinking—it’s a clear indication that your vehicle requires immediate attention. The most common cause is a severe engine misfire that can quickly damage expensive components like your catalytic converter.
The safest course of action is to pull over as soon as it’s safe to do so, avoid driving the vehicle further, and have it professionally diagnosed and repaired. While the repair costs might seem high, they’re typically much lower than the cost of repairing catastrophic damage that can occur from continuing to drive with these warning lights illuminated.
Remember that these warning systems exist to protect both your vehicle and your safety on the road. Heeding their warnings promptly can save you significant money and potential safety hazards in the long run.
