Check engine light with no other symptoms - Saab Forums

the blaab · #1 03-31-2010, 08:18 PM

HI all

We were out tonight went to the store etc. Got back in, the yellow check engine light (shaped like an engine) went on and did not go off when the other lights went off.
Conventional wisdom is gas cap or O2 sensor right?
OK so we got gas 2 days ago, would the cap take that long to trigger? We have like half a tank of gas.
02 sensor?
Other thoughts?
I searched this topic but everyone else had other symptoms with their check engine light
and the car is running absolutely top notch.
Any info is welcome!

Thanks!

Saab Fahrer · #2 04-19-2010, 07:37 PM

Really hard to say, because there are a handful of things that can cause the light to come on and have "no symptoms". The EVAP monitor takes alot of driving from a cold start to run, so it can take awhile to set after a fill up if the cap is loose, and can take a while to go back out (on its own) once the cap is tightened. There are other EVAP items that can also cause that, like faulty purge solenoid or leaking vent solenoid. and thats just ***uming its an EVAP code.

It could be a code for the thermostat, could be a code for the Ignition Cassette, etc.... the best thing to do, is have it scanned somewhere. You can either take it to a shop, or find a parts store that does "free code scans". Once you know the exact code number and description, you can start to isolate possible causes.

ibgummy · #3 04-23-2010, 11:29 PM

If you have a code reader see what pops up. If not take it to your local parts store. It could be a bad seal on your gas cap, you can try playing with it. If you get a P0455 message it can be a leaky hose, gas cap, or most likely like mine a vapor canister purge valve. They vary in price depending on the year of your car, mine was like 45. My car ran fine check engine light would even go out every now and then (most of the time when I tried to read the error). You can get them on e-bay if you are not in a hurry. it clear my problem up. hope it helps you.

zsazsa · #4 04-29-2010, 08:24 PM

My check engine light came on a few days ago, and I took it to the auto store and they said the code was reading something that had to do with gas and thay said most likely it was that I didn't close the gas cap correctly, sure enough I went to check and I did not close it all the way it was slanted. I also had put gas the morning before and drove it around back and forth to school, and the store and it didn't come on till the next night.

Stanley Woodbury · #5 03-08-2012, 08:34 PM

hi,
i have a 1999 9-3 4 door, 5 speed turbo, iv done a cold air intake and the tube that goes from the old air intake is now just vented due to no hole in the new tubing, soo the tube just comes out from the intake tube leading to the throtel body,

now theres oil lightly coming ot of that tube, asuming from the turbo, kinda far to be traveling, but why is that oil coming out? from where? also the oil light comes on at 1000rpms, or less, and only when the fan kicks on,? why?

the car has 200015 as of right now, runs good, oil changes, small tranny leak, i do travel quite a bit so every oil change i add 1/2 2/3 qt of oil, all synth,

thanks stan