Why Check Engine Light After Rain? And How To Fix It

The check engine light after rain may indicate a problem with the vehicle’s electrical system or the engine itself. The sudden increase in humidity and temperature changes can cause moisture to enter the engine and disrupt the electrical connections, leading to misfires or sensor malfunctions.

After a strong rainstorm, your check engine light may have come on. An illuminated dashboard might make you panic, but recognizing the problem can help you act.

The check engine light coming on after rain may signal many car issues. Moisture can cause electrical connections and sensors to malfunction and limit engine efficiency. Wet roads and puddles might harm the oxygen sensor and catalytic converter. In this post, we’ll discuss why the check engine light may come on after rain and provide alternatives.

Why does the Check Engine Light After Rain?

As mentioned above, a faulty spark plug might cause a cylinder misfire and a check engine light after rain.

If rainwater gets into your engine and there’s an electrical issue beneath the hood, several of your car’s sensors will notify you to a problem.

Water trickling into spark plugs after rain is a good illustration. Plugs can cause huge check engine light issues.

Old spark plug wires fracture and release small amounts of power. This will flash your CEL!

If you change your spark plug and wires, you may also need to replace the ignition coils. A faulty coil pack sets off the light when water pours in.

Why Check Engine Light After Rain?
Why Check Engine Light After Rain?

Oxygen sensor issues may cause CELs after rain. This sensor monitors automobile exhaust oxygen.

Poor fuel efficiency and spark plug and catalytic converter damage result from a defective O2 sensor.

If anything else goes wrong, the catalytic converter fails. A malfunctioning oxygen sensor or spark plugs and wires might be the issue.

Unfortunately, catalytic converter damage is expensive, therefore replace spark plugs and oxygen sensors promptly!

If your automobile runs OK and you don’t detect any of the aforementioned faults, it may be a false alarm. Nothing could be wrong with the car.

If rain causes check engine light, what should you do?

When the check engine light turns on after rain, inspect the spark plugs for issues.

If the light persists, check your vehicle distribution cap and plug wires for appropriate head insertion. If the ignition is fine, try other car plugs and connections.

Opening the automobile hood at night and starting the engine might reveal faulty plug wires. Watch the engine for a spark from the coil park or plug wires—that’s the cause!

See: Check Engine Light Flashing Then Solid (Causes & Solutions)

Spraying plain water over the spark wires and coil park can reveal the arch and heat it (typically a mild breaking sound).

Why Check Engine Light After Rain?
Why Check Engine Light After Rain?

Do not touch the spark wires while the engine is running. Even with insulated wires, it may shock you!

If the spark plugs, plug wires, or ignition coils are bad, replace them.

This DIY project simply requires two wrenches. It may take 1-2 hours if you’re unfamiliar with your car’s engine arrangement.

A scanner may help diagnose the problem code. This can assist you identify the problem wiring or plug so you may replace it instead of replacing them all.

When should you get your car fixed?

If you can’t find the problem, take your car to a repair shop. If changing the spark plugs, wires, or coil packs doesn’t work, see a professional.

Professional mechanics can identify all these engine issues and discover the source. They should then fix your car’s check engine light.

The mechanic will also scan the fault code causing the CEL to come on and diagnose it. This lets them fix your automobile and bring it back to normal.

Should you go to the shop with your car?

If your automobile check engine light turns on after rain, take it to the dealership for a diagnostic. Because the dealership may have vehicle-specific tools to diagnose and correct the issue.

Check with your mechanic first to see if they can help. If they can’t assist, visit the dealership.

What’s wrong with your car after it rains? Why does the check engine light blink?

In addition to the check engine light, rain may cause your engine to splutter.

This may be due to the distributor cap.

Check distributor wire for frays or cracks. Make that the distributor cap seal is intact.

Why Check Engine Light After Rain?
Why Check Engine Light After Rain?

If your distributor is malfunctioning, replace it.

We also advise avoiding driving with the check engine on and the car rocking.

This indicates a significant misfire, which can damage your catalytic converter and other components.

What’s worse: a steady check engine light or one that blinks after it rains?

Engine check lights might flash/blink or stay constant. Both indications suggest engine problems, but one is more important.

Flashing CELs indicate a more serious issue. It signifies your automobile engine has a major issue that needs immediate attention!

A steady check engine light indicates a minor issue. It might be anything trivial like a loose gas cap. You can drive for a year with such a problem without damaging your car.

Check Engine Light Flashing Due to Key On Position (Explanation)

However, we recommend finding out what causes your engine check light and fixing it.

How long can you drive after it rains with the check engine light on?

The rule of thumb is to not drive with the check engine light on.

Check engine light Blinking after rain is an emergency notice to halt driving due to engine misfire.

Take your automobile off the road, stop, and securely cut off the engine. Fix the issue before driving your car.

Driving with the check engine light flashing may harm more expensive components, costing you hundreds of dollars to replace.

Why Check Engine Light After Rain?
Why Check Engine Light After Rain?

Driving with the CEL on can harm a catalytic converter, requiring costly repairs.

If the CEL is stable, the issue may not be significant. Continue driving your automobile to your local auto repair shop for diagnosis and repair.

Water damage may cause your check engine light to illuminate after rain. Other situations like running out of petrol or acquiring gas might also turn on the light. We wrote articles on what to do when the check engine light turns on after running out of gas and after acquiring gas to help you troubleshoot and repair these issues. These articles give step-by-step instructions and helpful recommendations to identify and remedy the problem so you can drive confidently again.


This article shows that rain can affect your car’s check engine light. The check engine light usually appears after a thunderstorm because water gets into engine components.

Fortunately, avoiding this issue is easy. For optimal vehicle operation, regular maintenance is essential. In a downpour, changing spark plugs and other worn parts can keep water out.

Fear not if your check engine light appears. Before it gets worse, take your car to a repair. After a strong downpour, normal vehicle maintenance, including part inspections, can prevent the check engine light from appearing.

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