Audi A6 avant 2002 - Warnong lights - adrian19

I think I have owned this car to long now as I am having lots of niggley faults. I have owned the car from new ,97,000 miles. the latest fault came out the blue. on starting the car no warning light as you would expect. after a few moments the engine glow plug waring light starts to flash. if I then apply the brakes even though I am stationary no other light comes on, but when I release the brakes the esp and abs warning lights come on. If I drive everything works perfectly and engine performs well and brakes are perfect then the red brake warning lights and bleeps although everthing works ok. when I first start the car the diagnostic says all OK. I have checked all plugs and sockets around the abs system all looks ok. I have used a CAN OBD II diagnostic tool that plugs in but this comes up no codes I must assume from this that no fault is occurring . If this is an engine management system fault I think it could now cost more than the car is worth.

Pity really as the car is in immaculate condition. has anyone any idea which way I should go.I will appreciate any comments.

Audi A6 avant 2002 - Warnong lights - RobJP

Spend a little (only a little) bit of money taking it into a garage, and having them look at the faults, and seeing if their diagnostic tools can do any better.

Cheap diagnostic tools can't find everything. Why do you think garages (even independents) buy diagnostic gear costing in the thousands ? Would they do so if the gear which cost £200 or less was as good ?

Audi A6 avant 2002 - Warnong lights - 659FBE

Fair advice above, but the VAG diagnostic system is not infallible and won't detect some faults. This one may apply and some knowledge of standard faults is always useful.

I would suggest changing the brake lamp switch above the pedal - even if the lamps are functioning normally. Faulty switches are very common and can cause all sorts of problems with glow plug and brake warning lamps and also cruise drop-out etc.

This is because the switch is actually a double switch - one half for the lamps and the other for the engine ECU. If one half fails, the cross-check for operation in the ECU is not satisfied, and the warning lamps appear. This fault does not always leave a code set. The double switch is actually a good idea as the engine power will be cut if you try to accelerate and brake at the same time. It effectively prevents a "Toyota moment".

The switches are cheap (try GSF) and fitting is easy - but take advice as to the fitting method as the switch has been re-designed a number of times.


Audi A6 avant 2002 - Warnong lights - Peter.N.

I would be inclined to take it to a diesel specialist rather than a garage, they usually know what they are doing and so are cheaper.

Audi A6 avant 2002 - Warnong lights - adrian19

Thanks again for info. I will change the brake light switch then take it to a diesel specialist if fault still occures. I will keep you informed.

Audi A6 avant 2002 - Warning lights - adrian19

Thanks 659, it was the brake light switch, never would have thought that , obviousle you have experience on these matters. GSF had the updated version which looked quite different to the original. £9.90 and half an hour, job done. Thanks again for the info.

Audi A6 avant 2002 - Warning lights - 659FBE

Thanks for the feedback - it helps everyone and increases the knowledge base.

The 1.9PD is a gem of an engine - if it suits your job, look after it and keep it until it dies. At < 100k miles, yours is in its prime. You may well find the later VAG diesel engines lack the performance/economy balance of the engine you have.

I had a lift recently in a Skoda Superb Mk1 taxi with 330k miles on the clock - it ran just like mine.



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