1997 A6 1.8T intermittent cut out problem

[wytco0]

I have a 97 1.8T A6 which has done 145000 miles.

Recently I have had a problem with it, hoping that someone here can give me some pointers.

The car normally starts and runs fine however in the last few days it has developed a fault whereby sometimes after driving for several minutes the ABS light comes on along with a beep and the main error light and the engine cuts out completely. I can normally restart it straight away but this has now happened a couple of time on the motorway and I need to get it sorted out.


I ran a VAG-COm test and it did not show any errors.

I thought that because the ABS light was coming on this meant that it was an ABS fault however I spoke to a friend and he said that this would not cause poiwer loss and probably it was just that when the engine cut out the ABS light was coming on.

The car has recently had new front disks fitted so I thought that the fault could be related to that but I have spoken to the mechanic and he cant think of any way this could cause these symptoms. I have been out and done a couple of emergency stops and the ABS seems to be working perfectly so I am inclined to agree that the ABS light is probably reacting to the loss of power rather than the other way round.

Does anyone have any idea what could be causing this problem or of any tests that I can do to isolate the problem?

[Crasher]

You have a power supply problem which should have left fault codes on the engine ABS, air bags etc. Can you check it again? If there are no codes you will need to drive it with someone watching the lap top in engine 01, and observe the indicated battery voltage.

[wytco0]

You have a power supply problem which should have left fault codes on the engine ABS, air bags etc. Can you check it again? If there are no codes you will need to drive it with someone watching the lap top in engine 01, and observe the indicated battery voltage.


Hi Crasher thanks for the info. I think you have hit tha nail on the head!

I went out to try and do what you suggestde and found that the car would not start, when I turned the key the ABS lights came on with the tone and then the central red caution light stayed on. I noticed that the ABS light was dimmer than normal. Some time ago we had the ignition switch changed as it wasnt working correctly, I wondered if this was causing the problem and fiddled with the key a bit.

I also found that in this state VAG-COM would not connect to the car controllers.

After a bit of fiddeling and removing the key a few times the car started normally. I connected the VAG-COM and drove around for a while but the engid not cut out and all was fine.

There were a few errors listed below but I am not sure what they mean !:

Address 17: Instruments Labels: 4B0-919-xxx-17.LBL
Part No: 4B0 919 910 K
Component: C5-KOMBIINSTR.UN4 D01
Coding: 01442
Shop #: WSC 05701
Part No: IMMO
Component: IDENTNR: AUZ8Z0V4210015
IMMO-IDENTNR: AUZ8Z0V4210015
1 Fault Found:
01176 - Key
07-10 - Signal too Low - Intermittent
-------------------------------------------------------------------------------
Address 35: Centr. Locks Labels: 4B0-962-258.LBL
Part No: 4B0 962 258 B
Component: Zentralverrieg.,DWA D30
Coding: 04750
Shop #: WSC 00165
2 Faults Found:
01559 - Drivers Door
58-00 - Can't Lock
01560 - Passenger Door
60-00 - Won't Safe

[Crasher]

They are the hallmarks of a faulty ignition switch (and possibly the reader coil as well) but it is odd that it has already been done. Get a new genuine switch fitted, it is about an hours work.

[wytco0]

They are the hallmarks of a faulty ignition switch (and possibly the reader coil as well) but it is odd that it has already been done. Get a new genuine switch fitted, it is about an hours work.

Ok thanks, any idea how much a switch will cost? is this something that I could do myself? I dont like taking the old girl to Audi anymore as they charge almost what she is worth!

Re the reader coil should I change that anyway?

The switch was changed originally as it was broken, I had to turn it back on itself or the car would not start. I was told it was a known fault with them. It was done about 2-3 years ago.

[Crasher]

The switch is part number 4A0 905 849 C and costs £25.86 inc. VAT and can just be changed with the lock housing in place. You have to remove the air bag, wheel, column covers, stalk assembly and instruments. The reader coil/lock unit (remember, you loose the one key system) is 4A2 905 855 C. Changing the lock barrel is quite a lot more involved and means removing the lock housing from the car and drilling the housing to allow the barrel to be removed.

[wytco0]

The switch is part number 4A0 905 849 C and costs £25.86 inc. VAT and can just be changed with the lock housing in place. You have to remove the air bag, wheel, column covers, stalk assembly and instruments. The reader coil/lock unit (remember, you loose the one key system) is 4A2 905 855 C. Changing the lock barrel is quite a lot more involved and means removing the lock housing from the car and drilling the housing to allow the barrel to be removed.

Thanks Crasher, I think I will have a go at the switch and see if that cures it.

[Crasher]

Check the part number with the dealer before ordering.