Why My Car’s Check Engine Light Flashing Then Stops?

Check engine light lit like a Christmas tree can scare any motorist. Today’s car has a myriad of sensors and electronic systems which, then feed its brain i.e the ECU, if it detects that anything is wrong or missing, then it will promptly flash a check engine light. The check engine light flashing then stops is different from a continuously lit check engine light.

A flashing check engine light can be due to a major problem, flashing means the ECU is drawing your attention towards it. Let us learn something about it. 

What Causes Check Engine Light Flashing Then Stops?

The main causes of a flashing check engine light have been broken down into the following subsections-

1. Cylinder Misfire

Cylinder misfire is caused due to proper burning of the air-fuel mixture in the combustion chamber. It can be due to a faulty spark plug, a bad ignition coil, an improperly working fuel injector, or a leaky valve. The cylinder misfire will generally cause the engine to shake while idling and poor performance. 

2. Faulty engine sensors

A modern car engine runs on the mercy of millions of sensors, in order to produce that perfect air to fuel mixture. Sensors like a bad coolant temperature sensor, knock sensor or a camshaft positioning sensor can cause a flashing check engine light. It usually means that car has some serious issue and needs to be addressed soon. 

3. Turbo Overboost Situation

Turbos are fun in cars but they have a very complex system to keep them from going beyond a certain boost range. If there is any failure with the governing melanism, then it will cause the turbo to produce overboost which will instantly alarm the ECU. It can easily damage the whole engine if it is not attended in a timely manner.

4. Emission Related Problems

The emission control system in a car plays an important role these days as there are strict rules regarding them. If the ECU detects that all is not green in the tailpipe, then it will cause check engine light flashing then stops. In diesel cars, A clogged DPF filter is a leading cause behind it. These problems basically choke the engine and make the engine management system go crazy. 

How Long Can I Drive With A Flashing Check Engine Light?

In many of the cars, it is not recommended to drive at all with a flashing check engine light as it is a serious issue. But in most cases, you can drive to the closest repair shop. We do recommend towing your car if the repair shop is located far away.

Does Low Engine Oil Causes A Flashing Check Engine Light?

The engine oil system is not related to check engine light directly. But if the engine oil is so low causing the oil pressure to drop, it can cause a bad timing chain timing, which may cause misfires. Misfires cases a flashing check engine light.

How To Fix A Flashing Check Engine Light?

A check engine light flashing then stops is mostly an easy job to fix and in some cases, it can be fixed at home too. Here are the ways to fix it-

1. Attending The Ignition System

A misfiring engine is the number one cause of a flashing check engine light. Fixing that including attending to the ignition system through new spark plugs, ignition coils and the ignition leads, if the car has an older system. In the older cars, you have to also take care of the distributor and the distributor cap. Also, the timing should be up to the mark.

2. Repairing The Turbo

Turbo overboost can also lead to a check engine light flashing then stops. Turbochargers are designed to run within a prescribed boost limit, but overboost can really damage the engine. Generally, the wastegate and the turbo actuator in a variable vane turbo fail due to carbon accumulation. It can be easily disassembled and cleaned by an experienced mechanic. But in the case of several modern cars, it demands the replacement of the whole turbo assembly. 

3. Attending To The Emission System

An emission control system can also cause a flashing check engine light. Fixing the emission control system includes cleaning of the EGR valve, in the case of modern diesel the DPF filter or sometimes the catalytic converter gets damaged and needs to be replaced. In the older cars, the cleaning process was simple and could have been done in the driveway. But in the case of the modern car, they have a very complex plumbing present in the engine and it generally requires an experienced mechanic to attend to.

4. Replacing Bad Sensors

Check engine light flashing can be caused due to a faulty engine sensor such as a coolant temperature sensor or camshaft positioning sensor. Replacing them could be a very simple job or in the case of the complex German cars, may require the whole engine to be brought down from the car. In the case of engine sensors, there is not much of an option to repair them or to clean them.

Even if one repairs them or cleans them, then it is not guaranteed that it will work like a new one. Generally, a repaired sensor can fail within months so it is better to replace the whole sensor as they are cheap anyway. A bad sensor can also be due to faulty wiring and in case of wiring issues, the faulty wiring can be repaired very easily. 

How Much Will It Cost To Fix Flashing Check Engine Light?

In the case of a flashing check engine light, the cost of repair comes in a wide range of scale. If the cause of a flashing check engine light is a bad sensor, then it generally costs between $10 to $200. In case of miss firing, the ignition system can consume up to $500. If the turbo is faulty or the engine is worn out, then the cost can go upward of $1000.


Check engine light flashing is mostly due to a misfiring engine. Though not a major cause of concern, the car needs to be attended on a prioritized basis as the problem could be severe and it can cause complete engine damage. If you still have any questions, then feel free to comment and ask them away. 

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