I know how scary a flashing check engine light can be. It’s your car’s way of urgently flagging a potentially serious issue, a distress signal that demands immediate attention.
A flashing light usually means something’s wrong with your engine or emissions system. When the key is turned, the vehicle’s onboard computer runs a self-diagnostic check, and a flashing check engine light signifies that it has detected a critical problem that requires immediate attention.
In this blog post, I’ll discuss the reasons for the activation of engine flashing lights, what you should do when it happens, and how to troubleshoot.
If you’re looking for more in-depth guidance on troubleshooting a flashing check engine light, be sure to check out our guide on ‘Check Engine Light Flashing: What it Means and how to troubleshoot.’ This resource will provide you with step-by-step instructions and tips to effectively diagnose and address the issue.”
Reasons for Its Activation
These are some common experiences and reasons why the check engine light comes on:
1. Catalytic Converter Problems
The catalytic converter reduces harmful emissions. Issues such as overheating or a failing converter can trigger the check engine light and result in poor engine performance.
2. Faulty Oxygen Sensor
Oxygen sensors help regulate fuel mixture by monitoring oxygen levels in exhaust gases. When it fails, it can lead to decreased fuel efficiency and increased emissions, triggering the check engine light.
3. Engine Misfire
Misfiring engines are pretty common. This occurs when one or more cylinders in the engine don’t ignite properly, leading to incomplete combustion.
The check engine light may flash to signal this issue, as it can damage the catalytic converter and other engine components over time.
4. Loose or Damaged Gas Cap
You might see the check engine light if your gas cap is loose or damaged. It’s a reminder of how even minor issues can affect your vehicle’s performance.
5. Sensor Malfunction
Modern vehicles are equipped with various sensors that monitor different aspects of the engine’s operation. If one of these sensors malfunctions or provides incorrect data, it can lead to the check engine light activation.
6. Exhaust Gas Recirculation (EGR) Valve Issues
Problems with the EGR valve can result in increased emissions and reduced fuel efficiency, prompting the check engine light to illuminate.
7. Airflow Sensor Problems
The mass airflow sensor measures the amount of air entering the engine and is critical for proper fuel delivery. If it malfunctions, it can cause engine performance issues and trigger the check engine light.
8. Ignition System Problems
Issues within the ignition system, such as a failing ignition coil, can lead to misfires and trigger the check engine light to flash.
9. Vacuum Leaks
A vacuum leak in the engine’s intake system can disrupt the air-fuel mixture and cause engine misfires. Vacuum hoses, gaskets, or the intake manifold itself can develop leaks.
10. Failing Mass Airflow Sensor (MAF)
The MAF sensor measures the amount of air entering the engine and is critical for proper fuel delivery. A failing MAF sensor can result in engine performance issues and a flashing check engine light.
11. Overheating Engine
An overheating engine can lead to severe damage, and the onboard computer may trigger a flashing check engine light as a warning.
Causes of engine overheating can include a malfunctioning thermostat, coolant leaks, or a failing water pump.
12. Camshaft or Crankshaft Position Sensor Problems
These sensors play a vital role in engine timing and performance. Malfunctions in either sensor can lead to misfires and a flashing check engine light.
13. Fuel System Issues
Problems within the fuel system, such as a failing fuel pump, clogged fuel filter, or low fuel pressure, can cause the engine to misfire and trigger the check engine light.
What to Do When the Check Engine Light Starts Flashing
Here’s what you should do when you find yourself in this unsettling scenario:
1. Reduce Speed and Limit Driving
The first and most crucial step is to reduce your speed and limit your driving as much as possible.
From my own experience, I’ve learned that continuing to drive with a flashing check engine light can exacerbate the issue and potentially cause more extensive damage.
2. Avoid Heavy Acceleration or Braking
Gentle driving is key. Avoid heavy acceleration or abrupt braking, as these actions can put additional stress on the engine and worsen the problem.
3. Pull Over Safely
As soon as it’s safe to do so, find a suitable spot to pull over and turn off the engine. Stopping in a safe and well-lit location, away from traffic, is crucial for your safety.
4. Check Gas Cap
A loose or damaged gas cap can trigger the check engine light. Before panicking, double-check that the gas cap is securely tightened.
5. Inspect for Visible Issues
If you have some automotive knowledge and feel comfortable doing so, you can inspect under the hood for any visible issues.
Look for loose or disconnected wires, hoses, or anything out of the ordinary. However, avoid extensive tinkering if you’re not confident in your abilities.
6. Don’t Clear the Code
Resist the temptation to clear the diagnostic trouble code (DTC) with a scanner. Clearing the code may erase valuable information that could help a mechanic diagnose the issue.
7. Seek Professional Assistance
Perhaps the most important step is to seek professional assistance immediately. From personal experience, I can confirm that a flashing check engine light usually signifies a significant issue that requires expert diagnosis and repair.
Contact a trusted mechanic or a nearby auto repair shop to schedule an inspection. Explain the situation clearly, emphasizing the flashing check engine light.
Possible Repairs and Solutions
When faced with a flashing check engine light, addressing the issue promptly is crucial for the health of your vehicle.
From my own experiences and knowledge, here are some possible repairs and solutions that can help resolve the problems indicated by a flashing check engine light:
1. Diagnostic Scan
The first step is to conduct a diagnostic scan using an OBD-II (On-Board Diagnostics) scanner.
This scan will retrieve specific error codes (DTCs) stored in the vehicle’s computer system, pinpointing the issue. It’s essential not to clear these codes, as they provide valuable information for repair.
2. Addressing Misfires
If the diagnostic scan reveals misfire-related codes, the repair may involve replacing faulty spark plugs, ignition coils, or fuel injectors. Proper diagnosis is crucial to identify the exact component causing the misfire.
3. Catalytic Converter Replacement
If the catalytic converter is the culprit, it may need to be replaced. However, it’s essential to diagnose the underlying cause of its failure, such as engine misfires, to prevent premature damage to the new converter.
4. Oxygen Sensor Replacement
Malfunctioning oxygen sensors should be replaced with sensors compatible with your vehicle’s make and model. Replacing these sensors can help improve fuel efficiency and reduce emissions.
5. EGR Valve Repair
EGR valve issues may require cleaning or replacement. Regular maintenance and cleaning can help prevent future problems with the EGR system.
6. Ignition System Repair
Problems within the ignition system, such as failing ignition coils or spark plugs, should be addressed promptly to prevent further misfires.
7. Vacuum Leak Detection and Repair
Identifying and fixing vacuum leaks often involves inspecting hoses, gaskets, and intake manifold components. Once located, damaged parts should be replaced.
8. Mass Airflow Sensor Replacement
A malfunctioning MAF sensor can be replaced, but it’s crucial to use a compatible sensor and ensure proper installation to maintain accurate air-to-fuel ratios.
9. Cooling System Repairs
If engine overheating triggered the flashing check engine light, repairs may involve fixing the thermostat, repairing coolant leaks, or addressing issues with the water pump.
10. Camshaft or Crankshaft Position Sensor Replacement
Malfunctioning position sensors should be replaced with OEM (Original Equipment Manufacturer) or high-quality aftermarket parts. Proper alignment and calibration are essential during installation.
12. Fuel System Repairs
Fuel system issues may require the replacement of a failing fuel pump, clogged fuel filter, or repair of a damaged fuel line. Ensuring proper fuel pressure is critical for engine performance.
How Do I Reset My Check Engine Light?
Resetting the check engine light is a straightforward process. To reset the check engine light, you can disconnect the vehicle’s battery for a few minutes.
Start by disconnecting the negative (black) terminal and then the positive (red) terminal.
Leave the battery disconnected for about 15 minutes, which allows the vehicle’s computer to reset. Reconnect the positive terminal first, followed by the negative one.
Meanwhile, I’ll emphasize that this method merely clears the light temporarily and does not address the root cause. To resolve the issue, you should have the vehicle professionally diagnosed and repaired by a qualified mechanic.
Will Bad Spark Plugs Cause Check Engine Light to Flash?
Yes, bad spark plugs can indeed cause the check engine light to flash. Spark plugs play a crucial role in igniting the air-fuel mixture within the engine’s cylinders.
When spark plugs are in poor condition, they may not fire properly, leading to incomplete combustion, engine misfires, and an excessive amount of unburned fuel entering the exhaust system.
This can trigger the check engine light to flash as a warning of a severe issue that requires immediate attention.
If you experience a flashing check engine light, it’s wise to have your vehicle’s spark plugs inspected and replaced if necessary to prevent further damage and maintain engine performance.
Will Bad Spark Plugs Cause Check Engine Light to Flash?
Yes, bad or faulty spark plugs can indeed cause the check engine light to flash. Spark plugs play a critical role in igniting the air-fuel mixture in your engine’s cylinders.
When spark plugs are in poor condition, they can misfire, leading to incomplete combustion and unburned fuel entering the exhaust system.
This can result in increased emissions, reduced fuel efficiency, and potential damage to the catalytic converter.
The onboard computer detects these issues and may trigger a flashing check engine light as a warning of a severe problem that requires immediate attention.
If you notice a flashing check engine light, it’s essential to address the issue promptly by inspecting and, if necessary, replacing the spark plugs to prevent further damage and maintain your vehicle’s performance.
Conclusion
A flashing check engine light when the key is in the “on” position is a serious warning from your vehicle’s onboard computer that something is wrong with your car’s engine. It indicates a significant problem that demands immediate attention. Ignoring it can lead to more extensive damage, increased emissions, and decreased fuel efficiency.
Promptly addressing the root cause through professional diagnosis and timely repairs is essential for maintaining your vehicle’s health and ensuring your safety on the road. Remember, the check engine light is your car’s way of communicating with you, and it’s always wise to listen and take action.