The check engine light does a great job of providing an early warning that there’s something wrong with the vehicle. However, the downside is that you can rarely know what exactly is the problem, especially if it’s only flashing when accelerating.
If the check engine light is flashing when accelerating, the problem is isolated to the engine block, with the crankshaft position sensor, fuel delivery, or air intake being the most probable culprits. The first step toward fixing the problem would be to scan the vehicle with an OBDII diagnostic tool, and then clean or replace the problematic component.
What Is the Check Engine Light
The check engine light is a part of the car’s computer system. It’s connected to sensors throughout the vehicle that monitor emissions, fuel mixture, and engine performance. The light comes on when the system detects a problem.
Modern cars come with a variety of sensors. The most common ones are the oxygen sensor, mass airflow sensor, throttle position sensor, and engine coolant temperature sensor.
When one of these sensors malfunctions it will usually trigger the check engine light. In some cases, the problem might be with the car’s computer itself.
The check engine light is meant to be a warning sign that something is wrong with your car. It’s important to take it seriously and not ignore it. However, you shouldn’t panic either.
Causes of a Flashing Check Engine Light When Accelerating
1. Problem With the Fuel Delivery System
One of the possible causes of a flashing check engine light is a problem with the fuel delivery system. This can be caused by a dirty fuel filter, clogged injectors, or a faulty fuel pump.
The fuel delivery system comprises several components that work together to deliver fuel to the engine. If any of these components are not working properly it can cause the check engine light to come on.
While accelerating, the engine requires more fuel. If the fuel delivery system can’t keep up with the demand, it will trigger the check engine light.
2. Vacuum Leak
Another possible cause of a flashing check engine light is a vacuum leak. A vacuum leak can be caused by a faulty gasket, cracked hose, or damaged intake manifold. The possibility of a vacuum leak is increased if you have a turbocharged or supercharged engine.
A vacuum leak will cause the check engine light to come on because it affects the engine’s ability to maintain the correct air/fuel mixture. This can lead to poor engine performance and increased emissions.
3. Ignition Problem
Another possible cause of a flashing check engine light is an ignition problem. This can be caused by a faulty spark plug, bad wires, or a problem with the ignition coil.
An ignition problem will cause the check engine light to come on because it affects the engine’s ability to maintain the correct air/fuel mixture. This can lead to poor engine performance and increased emissions.
4. Problem With the Engine Sensors
Another possible cause of a flashing check engine light is a problem with one of the engine sensors. As we mentioned before, the most common sensors are the oxygen sensor, mass airflow sensor, throttle position sensor, and engine coolant temperature sensor.
A problem with any of these sensors can cause the check engine light to come on. In most cases, it will cause the engine to run lean or rich. This can lead to poor engine performance and increased emissions.
Fixes for a Flashing Check Engine Light
Now that we’ve gone over some of the possible causes of a flashing check engine light, let’s talk about some of the fixes.
The first thing you should do is use a diagnostic tool to read the error code and help you identify the real source of the problem. This will allow you to take the necessary steps to fix the problem.
Once you know what’s causing the check engine light to come on, you can take the appropriate steps to fix it. In some cases, it might be something as simple as replacing a dirty air filter.
However, in other cases, it might require more extensive work such as replacing an engine sensor or ignition component.
If you’re not comfortable working on your car, you can always take it to a mechanic. They will be able to diagnose the problem and make the necessary repairs.
Flashing Check Engine Light Codes
When the ECU detects an issue with the engine, the check engine light illuminates. Each error cached in the ECU is assigned a specific “P” code.
When the check engine light illuminates, the best way to determine what’s wrong is to connect a diagnostic reader and read the stored codes. Once you have the code(s), identifying the faulty component becomes much easier.
The following are some of the most common P codes related to the check engine light.
- P0300- Random misfire detected code
- P0302- Cylinder misfire detected
- P0420- Catalyst system efficiency below threshold
- P0455- EVAP system large leak detected
- P2463- Diesel particulate filter restriction – Soot accumulation
Frequently Asked Questions
How Much Does It Cost to Repair a Flashing Check Engine Light?
Relying on the severity of the problem, it could be something as simple and cheap as replacing a dirty air filter which would cost you less than $20.
However, in other cases, it might require more extensive work such as replacing an engine sensor or ignition component which could set you back a couple of hundred dollars.
Is It Bad to Drive When the Check Engine Light Starts Flashing?
It is not advisable to drive when the check engine light starts flashing. This is because it indicates that there is a problem with your engine which could lead to further damage if not fixed. If you have to drive, make sure to take it easy on the accelerator and avoid high speeds.
What Are Some of the Common Symptoms of a Failing Mass Airflow Sensor?
Some common symptoms of a failing mass airflow sensor are poor fuel economy, hesitation when accelerating, and stalling. When you notice any of these symptoms, it’s best to have your car checked by a mechanic as soon as possible.
Can a Bad Oxygen Sensor Cause the Check Engine Light to Flash?
Yes, a bad oxygen sensor can cause the check engine light to flash. This is because it will cause the air/fuel mixture to be too rich or too lean. This can lead to poor engine performance and increased emissions.
Replacing a bad oxygen sensor is usually pretty simple and can be done by anyone with basic mechanical skills.
Conclusion
When your check engine light flashes while you’re driving, it could mean you have an engine sensor problem, a vacuum leak, fuel delivery or ignition problem, or a major mechanical problem that will cause your engine to misfire.
You use a diagnostic tool, such as an OBDII, to read the error code and assist you in determining the true cause of the problem. This allows you to determine the appropriate course of action based on the error code.
A flashing check engine light is never something to ignore. It’s important to use a diagnostic tool to figure out what’s causing the problem so you can take the necessary steps to fix it. In some cases, it might be something as simple as replacing a dirty air filter.
However, in other cases, it might require more extensive work such as replacing an engine sensor or ignition component. If you’re not comfortable working on your car, you can always take it to a mechanic. They will be able to diagnose the problem and make the necessary repairs.
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