That's interesting. On ours the check engine light started being tempermental about a week or so before christmas. What I started noticing is that it would turn on when turning the car on in cold damp weather (drizzly) but even the car was indoors (garage). We've known about the gas cap and were always concienscious about it and didn't have problems for 1.5yrs. By the time I took the car in after I realized it wasn't the cap, checked it, filled up the tank, etc. I took it in and that morning it turned off. No codes were stored in the computer so they couldn't trouble shoot it.

Last night it turned on again and fortunately it stayed on this morning, after two restarts so I drove straight to the dealership where I left it on and they hooked it up. ECM-16 which is a the O2 sensor. So it's faulty! I'm getting it replaced Friday. I'm exited that there was a real fault and not an annoyance.

So a question is... how long does a code stay in memory? What event causes it to be purged?

Alberto