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Warning lightsUpdated 2026-10-24

Check engine light flashing

What it means

A flashing check engine light usually means the engine is misfiring right now. Back off the throttle, avoid hard acceleration, and stop driving if the engine shakes, loses power, or smells like raw fuel, because the catalytic converter may overheat quickly. If you keep driving, a basic ignition or fuel fault can turn into catalyst damage and a much larger repair bill.

Safety first

  • Back off the throttle, avoid hard acceleration, and stop driving if the engine shakes, loses power, or smells like raw fuel, because the catalytic converter may overheat quickly. From the article: Why Is My Check Engine Light Flashing?
  • If the light is flashing and the engine is shaking, do not continue driving. From the article: Can you keep driving?

Fix it step by step

Try the steps in order, easiest and safest first. After each one, tell us if the problem is gone.

Step 1 of 2

  1. Step 1: Read all codes before clearing themLow risk
    1. Read all codes before clearing anything.
    2. Write down whether the code is pending, stored, or history.
    3. Check whether the flash happened at idle, during acceleration, or under load.
    4. Inspect the simplest parts first: plugs, coils, connectors, vacuum hoses.
    5. Only then move to fuel pressure, sensors, or mechanical tests.

    Then check whether the problem is still there.

    From the guide section: How to read the codes > Pending, intermittent, and stored DTCs

  2. Step 2: Avoid driving hard if light is flashingLow riskIf nothing else worked
    1. If the light is flashing and the engine is shaking, do not continue driving.
    2. If it flashes briefly but the engine runs smoothly afterward, short and gentle movement to a safe place may be the least bad option, but avoid load, speed, and hard throttle until you read codes and inspect the basics.

    Then check whether the problem is still there.

    From the guide section: Can you keep driving?

Still broken after every step?

That is every step we have for this problem. Write down what you saw and which step you reached, then ask a qualified mechanic to look at the car. If it feels unsafe to drive, stop and call roadside help.

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Frequently asked questions

Why is my check engine light flashing and car shaking?

That combination usually means an active engine misfire. A flashing check engine light and shaking both point toward an engine misfire, and the risk is high enough that you should stop driving if the shaking is severe. Read the codes, then inspect spark plugs, coils, and fuel delivery.

Why is my check engine light flashing then stops?

A flash that stops can still matter because the fault may be intermittent, temperature-dependent, or load-dependent. The ECU may also store only a pending code at first. Scan the vehicle soon after the event, before the fault disappears from memory or becomes harder to duplicate.

Why is my check engine light flashing while driving?

While driving, a flash usually means the ECU is seeing a misfire severe enough to threaten the catalyst. Ease off the throttle, avoid passing or hill climbs, and pull over if the engine shakes or loses power. Then read codes and check whether the problem happens under load.

Why is my check engine light flashing then stays on?

A flash that turns steady often means the ECU first saw an active misfire, then logged a related fault after the condition persisted or changed. That can leave you with both a driveability issue and a stored emissions code. Scan for misfire and catalyst-related DTCs together.

Which step should I try first?

Start with "Read all codes before clearing them". The steps run from the easiest and safest to the hardest, so you can stop as soon as the problem is gone.

Sources

The steps above come from VFixCars articles.