Sometimes a drive-through car wash is the most convenient option for cleaning up the outside of your car on a busy weekend, as you can be in and out within a few minutes.
While these car washes are generally safe and efficient, why does the check engine light sometimes come on after a car wash?
The most likely culprit is that water has fallen into some part of your car. This is not necessarily a cause for alarm; once the water dries naturally, the check engine light should go off.
If it doesn’t, this could mean a misfire in your car, and you should have a mechanic check it out before you continue driving your car.
If your check engine light blinks, even sporadically, once your car has been washed, there are a few ways to get down to the root issue before calling your mechanic.
When in doubt, calling a mechanic could give you better insight so you don’t drive a potentially unsafe vehicle that’ll cost you way too much in repairs.
Water Has Fallen into Some Part of Your Car
If, at some point during the wash, water enters into some part of your car, it can easily cause the check engine light to come on afterward. It is one of the most common reasons behind the light coming on after a car wash.
In most cases, if water is sprayed for too long on the hood, it can enter the engine compartment and cause one of the internal components to malfunction.
Identifying what the issue is exactly and determining which component is malfunctioning can be difficult since the check engine light doesn’t specify the nature of the problem.
So, what exactly happens when water enters the car? It can cause many problems, including a cut in the ignition cable. Whatever the reason, the engine light usually goes off once the water dries.
There’s a Misfire in Your Car
Most problems caused by the water going into your car are easily resolved once the water dries.
It could indicate a more serious problem if you’ve waited for a while after your car has been washed and the check engine light hasn’t gone off. It could mean there’s a misfire in your car.
A misfire occurs due to incomplete combustion inside the engine. Misfires can occur either when you’re turning on your car or when the engine has already been idling for a while.
Common reasons behind misfires include issues with the spark plugs or the spark plug wires. An abnormally functioning ignition coil can also be a potential cause.
In case of a misfire after a car wash, getting a mechanic to inspect your car may be the safest option. Driving a misfired vehicle can be dangerous and may cause more damage to the engine and other internal components.
What to Do if Check Engine Light on after Car Wash?
What should you do if you’ve just got your car washed and the check engine light comes on?
Before you do anything, wait for about 20 minutes to allow the water inside the car to dry and then check if the check engine light goes off. If it doesn’t, you can try getting help.
As previously mentioned, the safest and easiest option is to get in touch with a mechanic and ask them to come and inspect your car if the engine light doesn’t go off.
This is much better than diagnosing and trying to fix the problem yourself.
Trying to drive your car back home or to the mechanic with the check engine, light is not recommended. It is unsafe and can cause more damage to the engine and other internal components of the car.
It can end up costing you a lot more in repairs.
Car Not Starting after Engine Wash
Water and electricity don’t mix well, and the engine bay of a car has many sensitive electrical components that can be damaged if they come into contact with water.
Therefore, if a car does not start after an engine wash, it is likely that water has gotten into one of these components and caused a problem.
Engine Misfire
This happens when the water shorts out one or more spark plugs, causing them to fail to ignite the fuel mixture in the engine’s cylinders.
If this is the case, you may be able to dry out the spark plugs and ignition coils with a cloth or compressed air, but in some cases, the damaged parts will need to be replaced.
Water Causes the Distributor Cap or Rotor to Malfunction
The distributor is responsible for delivering electricity to the spark plugs, and if it is not working correctly, the engine may fail to start. In this case, the distributor cap and rotor may need to be replaced.
To avoid these types of issues, you should try not to wash the engine directly. Instead, you can use a degreaser or engine cleaner and a brush to clean the engine bay. I
t’s also a good idea to cover sensitive electrical components with plastic bags or other protective covers before washing the engine.
How to Prevent Water from Getting in during a Car Wash?
You cannot prevent the water from getting inside the hood and on the engine and other components during a wash. The water can damage various internal parts and systems if it gets inside.
The good thing is that most modern cars have internal components protected against water, so you don’t have to worry about that.
However, if you have an older car, such as a model from the early 2000s, you might need to be more careful because the inner components of older cars are more vulnerable to damage from water.
Depending on the make and model of the car, you may need to take different precautions to prevent water from getting inside and causing damage.
What if the Check Engine Light Goes off after Car Wash
If the check engine light goes off after a car wash, it’s possible that water has caused a temporary disruption in one of the sensors or systems, leading to a false error code being triggered.
In this case, the light may go off after the water has dried up, and the sensor or system returns to normal functioning.
Conclusion
There are pros and cons to going through a drive-through car wash. These can save you some time but can end up costing you more stress, and potential car repairs should you not use a high-quality car wash service.
Sometimes your light isn’t an indication of a big issue, but it’s a hassle, either way, to try and diagnose the cause if it continues to happen.
If you continue to have problems with your check engine light every time you go through a car wash, it might be time to pull out your hose and bucket and get to work.
This way, you have more control over where the water goes, keeping the interior of your car safe while you make the exterior look fresh and new.