One of the biggest scams in the automotive/mechanic industry is the check engine light — this annoying disease that pops up and doesn’t care to ever leave your sight. A lot of the time, the light comes on because of some intermittent or rare problem, like a cylinder misfiring when your car was starting. So what’s the typical scenario: The light comes on, you go to your mechanic, he/she reads the code ($80), and then tell you “it could be anything, lets do a tune-up” ($150) — before you know it their suggesting new oil caps ($20) and timing belts ($$$).
I drive a 97 Integra, and every so often my check engine light comes on. It happens rarely, when I haven’t driven in a couple days, and I start the car without giving it any gas. Just after the car turns on, I feel a slight, baby rumble – cylinder misfired – check engine light comes on. The first time it happened, I went to the mechanic and they took $80 to read the code – crooks.
So now the real question, how do you shut it off? Most people think disconnecting the battery doesn’t work, and their right. It appears the cars computer system has some time delayed reset. Disconnect the positive terminal of the battery only, wait 10-15 minutes, re-connect and the check engine light should be off.

 

Before you clear the computer, I'd take it to a Pep Boys or an AutoZone. 9 times out of 10 they'll read the code for free. Then you can look it up yourself in case it is something really critical like low oil pressure. If it keeps coming back on with the same code, you may have a bad sensor.

 

my check engine light on my 1986 montero turned on about 45,000 miles ago, I think. I forget how many years it has been on. Now has 177,000 miles or so. Still going strong. and,
"never-gets-stuck" anywhere!