Random CEL

[bmwade]

Just filled up and got a random CEL as I was leaving gas station! Could it be bad gas or something like that? No noticeable difference in driving, revs/idles fine and power seems to be there. Turned car off then back on, still there. Any ideas on what it is?

[Chung]

My bad guess is the evap system. Probably should have it read and cleared if it is to see if it comes back.

[lswing]

Many have had the gas cap, just didn't get tightened correctly/enough. Scan and clear codes...VAG-COM RossTech....

[RSSIK]

^^^ Check gas cap ^^^ tighten, then reset. If light returns for same code then u have a leak or bad gas cap.

[bmwade]

Thanks! I checked gas cap but it was tight. Light stayed on for about 30 miles (and several start ups) while I was running errands, then randomly disappeared the last time I started it.

[marklar182]

Yup, Evap. N80 is probably going out.

[bmwade]

Exactly what I wanted to hear lol I guess I'll keep watching it and see if this happens again!

[Justin9212]

Evap purge valve may be on its way out.

[bmwade]

I have limited technical knowledge...so I have a question: Other than giving a CEL when its going out what does the valve or evap system actually do?

[marklar182]

I have limited technical knowledge...so I have a question: Other than giving a CEL when its going out what does the valve or evap system actually do?

Routes fuel vapors from the tank/fuel system into the intake for combustion instead of venting them to atmosphere and making the hole in the Ozone bigger :)

[bmwade]

Routes fuel vapors from the tank/fuel system into the intake for combustion instead of venting them to atmosphere and making the hole in the Ozone bigger :)

So it does a good thing but not a strictly nessisary system? Like if it fails it's not an emergency?

[marklar182]

Nah. You will be fine. Car may run a little rough but not a show stopper.

[lswing]

I got the EVAP error about 6 months ago, cleared, been fine since, fingers crossed as usual....

[bmwade]

help me understand...

I'm guessing this means bye bye TC? but what's the engine issue? I'm getting a bit of rough idle for about 30 sec first thing in the morning, then its fine. and this morning i noticed a new symptom: some smoke then it went away when the idle smoothed out.

[lswing]

Yep, replace the TC before it takes your trans with it. ACE rebuild...

[bmwade]

Is it just me being stupid or is their website down?

http://aceconverter.com/index.php?main_page=index&cPath=18_31