[Red Leg]

Hopefully someone will be able to help me out. Ive got a 09 VW CC VR6 with a "check engine" light trouble. When it came on i brought it to auto zone and they said the code was for a minor vapor leak. i disconnected the battery and the light stayed off until a few day after i got gas. another thing that is weird is if we get a 90 degree day, the light will go out. It usually comes back on in a week or so. i was going to replace the gas cap before bringing it to the shop but i wanted to check with you guys first.

 

[LINDW4LL]

What's the actual code you're getting? But yes, it's very likely that your gas cap is bad.

 

[ChristopherG]

If you're going to be working on the car regularly invest in a scan cable and program for your laptop. The generic scan that Autozone offers will give you all sorts of false readings and is in general pretty worthless.

It could be the gas cap or a problem with the leak detection pump. It's hard to tell without the diagnostic codes.

It is well worth the $350 for the software and cable if you are going to drive VW or Audi cars for a while.
You'll want a version that supports hex usb and can bus systems.
PM if you need more info.

 

[Red Leg]

the piece of paper with the codes on it went missing. i bought a new gas cap, now i'll have to drive it a bit to see if it goes out.

 

[TheEngineer]

Find someone local with a VAGCOM system.

 

[Red Leg]

replaced the gas cap, drove around for a couple of days and no change...bringing to the shop tomorrow.

 

[Red Leg]

To all that have been glued to their computers about this thread, im happy to say that the check engine light did go off. took a couple of days of driving. keeping fingers crossed it will stay that way.

 

[86JR]

It will come back on again.

One comes on on my car about once every 2 weeks, i just ignore it.

 

[LINDW4LL]

It will come back on again.

One comes on on my car about once every 2 weeks, i just ignore it.

He replaced the cap, so I assume it will stay off now. It does take some time for codes to disappear after the issue is fixed if you don't clear them.