I got a 2001 1.8T manualA6. Since yesterday yellow engine sign on the dashboard stays on permanently with engine running, normally would go off once engine has started running. Engine is starting andrunning as usual, I haven't noticed any new symptoms. I have changed spark plugs to Bocsh ones about a month ago and noticed slightly more engine vibration at idle.

Going to Audi dealler would be a complete rip off. My experience of Audi/VW dealership in the UK so far was really disastrous. Its a very nice car with a verypoor qualityservice at the dealer unfortunately (speaking of UK East London dealers).

If someone got any idea as to why the light stays on, please advise. I would be really greatful. Many thanks in advance.

might just be emissions issue. try opening the gas cap and tightening it again until it clicks. If you filled up in the last day or so, and put it on wrong, this can set it off I believe.

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"Your Kung Fu is very good, but it's no match for the fury of my ancestors"

'03 A6 4.2 Sport/Lux 18's. Stock otherwise (except for Aftermkt. Floor mats which add 22HP)

You need to scan the ecm and post your faults. Theres about a million things that can turn that light on.

many thanks! i have ordered vagcom, will test and post the faults as soon as get the software.

finally got my vagcom
here what i found:

fault: 16795
Secondary Air Injection System:
Incorrect Flow Detected
P04111 - 35 - -

i got no idea what the secondary air injection system is and where the flow sensor is located.

If I knew off the top of my head I'd tell you directly, but I don't. However I've read about it a bunch of times on here in the past. Use the Search feature and type in that code number, and I'm sure you'll get a bunch of different posts about it.

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99 2.8QM

"I've always kept an open, honest relationship with my daughter. Maybe that way she won't fall for the same sh*t her mother fell for." Robert Schimmel

a pipe is off on the secondary air system that's why the system detects a flow issue so check all pipes and vacuum lines

many thanks for all the advice

Checked all the pipes. A hose from the air filter housing to the pump had a little kink at the point of connection to the filter housing, but it was not fully blocking the air passage and must have been there for at least 6 month (the last time i changed the air filter).

Also checked air pump relay, fuses, seemed to be working.

When started the engine from cold the combination valve made hissing noise for about 30 sec, so I assumed the pump was working and didn't test it (have to go under the car to access it [>:])

Cleared the fault, test drove it, no yellow light so far... Will see whats gonna happen after few more cold starts.

Cheers!