MKN

Just got my car fully serviced a week ago. Today, while I was driving, the yellow Check Engine light came on. It is not flashing but remains lit. I have read about some of the problems that can cause this but any thoughts will be appreciated. I presume I have some time tbefore I take it back to the dealer. BTW, mine is a A6 Quattro.

Muhammad

Obvious is the gas cap, or low quality fuel, or an O2 sensor/emission-related part failure. 85% of the time it's the O2 sensors being picky for some reason. Often it has nothing to do with the actual sensors rather something like a plugged fuel filter, bad fuel, etc.

Wowdi

- Make sure gas cap is tight securing it with at least three "clicks".

- Wait for about five days for the Check Engine light to go out.

- Bring the car in for service if the light stays on.

My light went out but would come back on after a few days. The dealer gave me a hard time about admitting that it was a hardware failure. I bought VAG-COM to read the malfunction codes to verify that it was an O2 sensor glitch and took a screen print to the dealer. It turned out the my O2 sensor was indeed bad and had to be replaced. No problem since then. Left me frustrated with my dealer.

phred

In the dealer's defense, 99% of the time it really is just the gas cap. I read in an article somewhere that these "check engine" idiot lights are especially idiotic and go off all the time for no good reason (thanks, OBD II).

MKN

98 A6 Quattro with 45k miles on it. Thanks...

Richard Solomon

You've <b>GOT</b> to read the code to know whether there is a serious problem or not! A lot of people make a lot of noise about blinking vs steady check engine lights...I believe that careful reading of the manual will show that this (blinking light) indicates a situation which can damage the <i>catalytic convertor</i> - and has nothing to do with whether catastrophic engine damage will result.

My gone-but-not-lamented '00 threw a steady check engine light for me sometime back. The cause: both banks running too lean (MAF sensor faulted and replaced). I have Vag-Com, so I <b>knew</b> what caused the light - and I took the car in to the dealer immediately.

Call me paranoid, but lean running is a <b>bad</b> thing, and should not be tolerated for the 2+ weeks that a "scheduled" appointment would have required.

If you refuse to buy a scan tool like Vag-Com, drop by your dealer and have them scan the car for you. If the code is for a loose gas cap, they can clear it and send you on your way happy. If the code is serious, you'll avoid possible engine damage.

Just my $.02 (non-inflation-adjusted),

MingBlue2.7t

The check engine light is the 'most frequent reason for Audi A6 owners to visit their dealers', according to my dealer and his manufacture's rep. The A6, and other Audi's as well for that matter, has a 'very sensitive' system that requires a perfect seal in every connection, or the light comes on. If it's 'on' steadily, it could be serious, but likely not. I've had mine come on twice in 5k miles. If you let your car idle for more than 10 minutes, it will almost certainly come on, or if you refuel with the engine running. And, of course, there are many other scenarios that will produce the same indicator light. Audi is 'working' on getting this fixed. They are looking into ways to seal the system better, before delivery. Most Audi dealers have taken delivery of a new tool that allows them to quickly isolate the problem. It includes a 'wand' that amplified sound. The tech uses headphones while waving it over the car. Any leak in the emissions system sounds like a tornado in the headset. That allows them to get the leak, regardless of how small, repaired, quickly.

Finman

your leasing...then who cares?

QCRAZY

...of ownership (used car). After I finally got it in at the dealer it was a broken vacuum line. The line from the pass side secondary air valve!! Whatever that does??

Wowdi

Amen to reading codes and VAG-COM!