VW CEL

Trying to track down the source of an intermittent CEL in my 04 VW. I don't have a scantool but I have found a pattern. Fuel below 1/4 tank = CEL, Open and close the filler cap CEL resets. Big weather front coming through = CEL, Open and close the filler cap CEL resets.

So I suspect there is a pressure switch somewhere related to keeping the fuel tank vented correctly. But, I haven't found it yet.

Suggestions? Other ideas?

Remove the bulb. It's the only way to keep it from coming back on.

First--get a Bentley Manual on CD or DVD. Then check the lines to and from the tank up the filler neck. Also, get a VAG-COM diagnostic harness and software from Ross-Tech.

Year, make and model as well as engine type would be helpful.
Was the car ever in a crash or collision?

is there a way to pull codes with no scan tool on these?
I know there is for older toyotas and nissans, among others.

rustyvw wrote: Remove the bulb. It's the only way to keep it from coming back on.

Yeah, its a mkIV, I thought the bulb would have to be out for it to not have a CEL showing.

Really though, it could be the seal on the gas cap even doing that. If not, it very well could be a sensor that is causing that.

If you have an account for vwvortex.com, you could fight your way through the retarded stance crowd into your regional forum and ask if someone has a VAG-COM there you could use. Because this is all speculation right now.

Auto zone will let you use their diagnostic tool. Sounds like gas cap.

vwcorvette wrote: First--get a Bentley Manual on CD or DVD. Then check the lines to and from the tank up the filler neck. Also, get a VAG-COM diagnostic harness and software from Ross-Tech. Year, make and model as well as engine type would be helpful. Was the car ever in a crash or collision?

I haven't been able to find it on the Bentley. I'll take another look at the Bentley, and behind the fender liners, and try swapping the cap. Thx.

04 VW R32, 3.2l V6, Original owner, no accidents, 40k miles, no winters

Buy a scan tool, find out the codes. You can get one for less $100.00 I own a $4900 Snap On one, a $500 Blue Point one and a $69.00 Autozone one... guess which one gets the most use?

Get the code, then Google it. Likely you have a secondary air valve (N80) that needs replaced.

In reply to John Brown: Thanks much!

In reply to Drahthaar:

Problem found and solved, hopefully. Engine coolant temp sensor. Finally failed completely and threw a consistent code. The other stuff was coincidental. P3081 Engine not reaching proper temperature in case it helps anyone else. Apparently a common failure from a bunch of bad sensors.

Anti-stance wrote:

rustyvw wrote: Remove the bulb. It's the only way to keep it from coming back on.

Yeah, its a mkIV, I thought the bulb would have to be out for it to not have a CEL showing.

I wonder if VWs throw a CEL for having a burnt out CEL.

Glad to hear you discovered the issue.. funny how it was nowhere near the problem

Coolant Temp Sensor failure is pretty common. I replaced the one in my car a few years ago and need to again (planning to wait until a timing belt change this fall when I'll have the coolant drained anyway). If it was a bad batch, it must have been a large batch...

Pulling the bulb won't help you if you live in an area that uses the OBD II port for emissions tests. A CEL = automatic failure. While Mk VI's a prone to CEL, the fix is usually pretty cheap and easy.

Removing the bulb won't remove the code.

In reply to Ian F:

Rumor mill has it that new ETS's with green plastic are OK the ones that are black have a problem. I saw it on the internet so it must be true.

They're cheap and pretty straight forward to change. But, I'd prefer not to have too.

I have the green one in my car. OE one was green too.

I often joke Bosch engineers used to work for Lucas...

Ian F wrote: I have the green one in my car. OE one was green too. I often joke Bosch engineers used to work for Lucas...

Joe Lucas invented darkness, but it took Robert Bosch to perfect it.

The sensors VW spec are of the cheapest possible construction. A similar sensor on just about any other Euro car will seldom fail.

There is a reason VW can sell cars for less money than other German manufacturers.

Fun fact: It actually was the British who invented the CEL. You pulled the flashlight out of the glove box and went up to check your engine with the light when it crapped out on a dark drive home.

A poster on another board says 'the CEL on a TR8 is the flames erupting from the bonnet ...'

Why is the CEL the only thing tha VW makes that works properly?

Wally wrote: Why is the CEL the only thing tha VW makes that works properly?

QFT!!!!!!!!!!