Rep Power: 0

Recently I removed, cleaned, and replaced the K&N air filter for my 2008 Civic DX. One has to remove the wire harness that lies over the air filter housing in order to do this. While this wire was disconnected, I also turned on the ignition so that I could adjust my windshield washer aim. That caused the engine malfunction light to come on when next I ran the car, since it had in mind that there was a problem with whatever sensors are hooked up to that wire. The warning light still had not gone out several days later.

I was sure there was no intrinsic problem with the car, it was just caused by the procedure I used. The dealer tolds me he'd be glad to hook up his computer to it for $89.95, and turn off the warning light. No thanks.

Instead, the easy fix was to disconnect the +ve terminal of the battery for a while, then reconnect. All is well again except that the clock is wrong. Problem solved.

 
Rep Power: 243

Autozone will also reset it for free.

 
Rep Power: 149

It will store that error but usually after a few dozen starts and stop, it will also turn itself off after it reads enough times all is OK.

 
Rep Power: 517

The light would have gone out by itself after about 5 starts or so.