If you’re reading this guide, you’ve probably noticed your check engine light started blinking after car wash. And you’re now trying to get ideas about what could be the cause. If that’s you, this guide is for you.
You see the check engine light after car wash because water has gotten to parts of your car engine that shouldn’t get wet. The light usually goes out on its own after the water evaporates and your vehicle goes through several drive cycles.
In this guide, you’ll discover more information about your check engine light (CEL) coming on after a car wash, what triggers it, and some fixes that can help solve the problem.
What causes check engine light after car wash
Check engine light comes on after car wash due to water getting where it shouldn’t be. This is especially common after you hose down your engine. This leads to electrical hiccups that cause your car sensors to take funny readings, hence the check engine light shows.
To be more precise, the water can get to your electronics and electrics, including the coils and the plugs.
A good example is when the water from the car wash drips into the spark plug wire and then runs down into the engine head, leading to occasional short. Whenever water runs down the plug wires, the CEL will show up.
Water getting to the MAF (mass air flow) will also trigger the engine check light.
Needless to mention, this results in misfires. And the result is the check engine light blinking to alert you of an underlying problem.
If you have your car engine sprayed down at a high-pressure car wash, with water getting shot into each and every engine crevice, then you’re even more likely to deal with the check engine light coming on.
In some instances, the error codes, and hence the light, tends to clear themselves once the water in the engine evaporates and the vehicle undergoes several drive cycles without a repeat of the problem.
What to check when engine light comes on after car wash?
Whenever you hose down your car engine, you get many things wet that aren’t supposed to get wet. And this becomes the root cause of your problems.
Start by looking for simple non-car wash related issues that can trigger the CEL, like the gas cap being loose. If it’s tight, then you can proceed to look into other parts as explained below…
With this in mind, the best place to start checking when the CEL light comes on after the car wash is the electronics/electrical of your car.
Start by checking the wiring and connectors. They could have some moisture that’s causing the problem.
A bad seal on the wiring (epically in old cars) could also have allowed water to easily pass and accumulated in the plug wells.
Here, the best solution is to dry everything out as much as possible. A hair dryer or compressed air can help with the drying process.
Remove all the spark wires and use compressed air to blow out the plug tubes. Put a dab of dielectric grease inside the plug wires boot before you put it back in place to solve the problem.
Just make sure you don’t hold appliances like the hairdryer on your engine components for too long as they produce heat that can cause damage and leave you with problems to solve.
The ultimate best bet is to scan the error codes to see what the problem is. This way, you can solve the issue for good and hopefully prevent it from happening again.
How do you keep water from getting where it shouldn’t during car wash?
If you’re careful enough, you can keep water off the engine components that shouldn’t get wet and ensure you don’t get the CEL after the cleanup exercise. Or follow our simple advice and just don’t bother cleaning the engine bay!
Before you do anything, you’d want to start by protecting everything under the hood that shouldn’t get wet. This includes the alternator, distributor caps, and generally all the electrical and electronics.
Always keep in mind that water and the top of your engine compartments DON’T mix. If you plan to do any engine bay detailing in feature, better to use a hand and spray bottle. This will save you the headache of dealing with CEL light blinking.
After all, it’s better to have a dirty and ugly engine that runs smoothly than a clean and shiny one that won’t perform properly.
We advise against using a power washer for the engine bay detailing as it will likely force water where it shouldn’t go.
Or you can avoid cleaning the engine bay altogether. But if you must it, then use one with a fan setting, so it sends water in gently and soaks various rather than soaking them at high speed.
And make sure you shoot it from a distance far enough to ensure no pressure will force water to get into engine crevices.
Also, avoid using steam to clean your vehicle engine. While there’s nothing wrong with using it and it’s safe for engines, steam can easily go into holes and cracks much smaller than water can.
Can you drive my car with an engine light on after car wash?
It is not recommended to operate the vehicle if the check engine light starts blinking after the engine wash. This is because the underlying problem is most probably a misfire.
Driving a vehicle with a misfire can cause a high quantity of unused fuel to enter the exhaust system where it burns out the cat and causes costly damages.
The best thing to do is have the error codes checked by a local auto repair shop. You can also check it on your own if you have a scanner. Next, you should look up what the codes are about.
If they’re for misfire, then you should consider going to the dealer. They’ll pull the codes from the system, diagnose them, and then fix the issue.
Note that the issue will be much easier for them to fix if you do it quickly without operating your vehicle further. You just tell them it happened after a wash and let them do the rest.
How do you reset check engine light after car wash?
If you’re not lucky enough for the light to go out on its own, then you can do a couple of things to help reset the check engine after car wash.
One method is to disconnect the battery negative terminal for about 10-20 minutes. This should hopefully clear up the light and make the error code disappear.
Another method is to use the OBD2 scanner to get the error code that comes with the CEL. The code will then tell you what’s wrong with your vehicle.
If these methods don’t work for you, take your car to the dealership’s service center. They’ll easily figure out what set off the light and fix it for you at a cost.Car washes are a great way to keep your vehicle looking clean and shiny, but did you know that they can also trigger your check engine light? If you’re experiencing this issue, don’t worry – our articles on what to do when the check engine light comes on after getting gas and what to do when the check engine light comes on after a repair can help you troubleshoot and fix the issue. We provide detailed guides and tips to help you diagnose the problem and determine the best course of action. With our help, you can get back on the road safely and confidently.
1. Can a car wash trigger a check engine light?
Yes, a car wash can trigger a check engine light when the water gets into parts of the engine that shouldn’t get wet. This is especially true for electronic and electrical parts. When they get wet, they start failing, resulting in check engine light showing up.
2. Can washing your car damage the engine?
Washing your car cannot damage the engine if you do it correctly. We have already outlined some helpful tips on how to safely clean your car engine without risking water getting to parts it shouldn’t.
Next time you notice the check engine light blinking after you drive out of your local car wash, don’t panic. This occurs when water gets to areas of the engine that should stay dry. The water may have gotten to the plug, plug wires, or the coil and your car system didn’t like it, triggering the check engine light.
We hope that this guide has provided you with the information you need on how to handle this issue when it shows up. We have also shared additional tips to help you prevent the problem from happening again in the first place.