Engine light is on after washing engine?

I took my Ford Escape to the car wash and washed off the engine. It drove home OK, but today it is shuddering, the RPMs guage will only go halfway, and the check engine light is on. What up?

A good guess is that water got into the wiring. You will have to find out what code or codes is/are lighting the check engine lamp.

Probably a PCV valve or some other part of the emission system, let it dry out and see if it goes away, otherwise you'll have to replaced it.

You got water in the electronics most likely.Usually they'll straighten out after a day or two when everything dries out.

So

Never wash a fuel injected engine, it will cause problems forever as bad as a flood car.

That's why you don't wash an engine. Now you'll need to blow out every harness connector to get the soap and water out of the connections!

I'll guess it's misfire from wet ignition components. Dry drying out the inside of the distributor. Wipe it with a cloth moistened with wd40. Do the same on the spark plug wires.

Pop off distributor cap and leave it off for several hours(if you are in a hurry then either a pistol hair dryer or compressed air is blown into the distributor to dry it out and dry out inside the cap. Usually if you are going to wash an engine (a plastic bag is put over the distributor so you don't stuff it full of water) and then when you finished washing, you take the plastic bag off and the cap is dry. Then there's no problem. I'm guessing that is what the problem is. The engine is misfiring or not firing on some cylinders because the spark is not getting to the spark plug. This happens… Usually right there in the car wash. You are stalled there. But it can happen later. You got LUCKY.