check engine lights

[moondoggy]

2000 carrera2 with 54k miles. Last month check engine light came on and I found that I hadn't screwed gas tank cap on after filling with gas and lost the cap. Bought after market nonventilated gas cap made by Stant in USA but light stayed on anyway until l disconnected battery . (Similar time period I found a nonethenol gas station that I began using infrequenty.) Anyway, light came on again and after disconnecting/connecting battery again, it went out. Today it came onagain. Don't believe disconnecting battery again is the answer. Could the aftermarket gas cap be my problem (and maybe mixing nonethenol with ethenol gas here in central VA?). Also, I haven't found the tool to check what codes are from the check engine light. Don't recall if original porsche gas cap nonventilated. What do you think?

[Loren]

Sorry, it is just guessing without the fault code(s).

[JFP in PA]

While Loren is spot on about the codes, I can say that we have not found an aftermarket gas cap that works as well as the OEM units. Eventually, the Stants and other major brands tend to start throwing codes associated with vacuum leaks in the fuel vapor recovery system. We had several customers replace the OEM caps with aftermarket locking units, all of which eventually started to throw codes. Putting on an new OEM unit fixed the problem.

Get the codes read and report back, if it is one of the codes associated with a gas cap leak, getting the OEM unit is a cheap, easy, and near permanent fix.............

Edited November 28, 2012 by JFP in PA

[moondoggy]

Thanks for the suggestions. I'm having the check engine light checked by the tool to determine the problem next week. I'll keep in touch.

[creekman]

Question: I changed out the engine air filter yesterday, then proceeded to do some cleaning using gunk and washed the engine down. I covered the alternator and the MAF inlet. It wasn't a heavy soaking since I did this in my garage. When I had the air filter canister back in the car and started it I got a solid CEL light. Also I had a miss at idle. I went by Auto Zone and they said I had a PO301 code. That pertained to No. 1 cylinder and relates to possible Vac leak, injector fault, hi or low fuel pressure and possible ignition system fault - spark plug. After driving 3-4 miles today the miss seems to have gone away and all is normal, I think...

My question is, will the CEL go off by itself, assuming it was just some water on the coil, or wires, or does it have to be turned off?

Thanks,

[JFP in PA]

If the 0301 code was the only one, it will go out by itself with enough driving. You could also take it to one of the auto parts stores advertising free use of a scanner and clear it as well.

[moondoggy]

Code is P0455 which supposed to mean evaporator emission system leak detected, gross leak/no flow. Maybe vacuum line or egr valve going bad. Is this a DIY?

[JFP in PA]

The P0455 code is for a problem with the tank pressure sensor measurment, usually a classic "bad or missing" gas cap code. I could also be other EVAP ventilation system lines leaking, but I would get rid of the aftermarket cap first......

Edited December 3, 2012 by JFP in PA

[Ahsai]

Why not get the OE cap (<$10 from Sunset Porsche) to eliminate that as a problem first? I just replaced mine preventively as there are small cracks on the o-ring on my old cap. The o-ring is already $5 or so so I decided to just get the whole cap.

[987_RDC]

Yep P0455 is large EVAP leak. Occurs during the initialization of EVAP when system attempts to allow tank to hold vacuum. On older Ford Exporer it was 1st the gas cap but then the filler neck that was bad. All signs do point to ****ty seal on the aftermarket cap.....

Edited December 4, 2012 by 987_RDC