A6 gone into sleep mode

[Bloobat]

Major crisis with my new shape 2004 2.4L petrol A6 - now done 80,000 without fault but last Sunday everything apart from virtually the radio was dead when I came to start it after a shopping trip - no ignition lights, no central locking, no auto hanbrake NOTHING. RAC came out and checked the battery which was ok and tried to re-set the car but couldn't. Towed the car to a local garage after having to manually rewind the brakes and after a couple of hours work on the following Tuesday the garage thought it was the "body control unit" but took it to the local Audi main dealer for a second opinion. They have told me that they cant get the car to talk to them so want to replace "the access control unit" so that they can do a further diagnosis. The part is due to them tomorrow - about £850 costs after this unit replaced and still dont know what the fault is!!!!! What a situation - total money haemorage just before Christmas . Why do modern cars have to have so many expensive control units??? Anybody else had any similar problem???? I have a horrible feeling that final costs are going to be into the thousands.......

[Peter D]

Is it under warrantee from the place you purchased it. ? Regards Peter

Sorry miss-read that, new shape, not new to you..

[Peter D]

I have just had a look at the circuit diagrams for your car and assuming your car was a manual box, then the engine should have cranked over and the side lights should have operated as a minimum. You must have lost a main power feed for these not to work and that is why Audi can not diagnose the problem as all the ECU's have shut down. I do not think that swopping ECU's is going to fix this it needs a good tech with a meter. I'll look further later. If you had not said the radio worked then I would say that S205, the main fuse 150 amp has gone or possible high resistance. May be that would allow enough juice to power the radio but nothing alse. Regards Peter

[Peter D]

Are you sure this is a 2004. 2005 4F2 is electrically different and there is a battery isolation relay, but not all power is lost to the car which may explain the radio. Look at you VIN number. I have just discovered that the Battery Isolation relay was fitted from July 04. However this only isolates the battery form the alternator and starter. Another possibility is the Energy management control unit had failed and removed the earth connection from the battery and there may he enough of an earth via the radio aerial anp to power the radio. Regards Peter

[Bloobat]

Thanks for your replies Peter D - car was first registered on 01/09/04 (I have had it since February 2005). The VIN no. has 4F15N in it. I dont think there is a lot I can do but being with an Audi main dealer hopefully they can find the problem. They did say that if it wasn't the acess control unit they would not charge me for it as they can send it back unlike other non Audi garages. Dont know whether the lights worked but the RAC man checked all the fuses, the 2 boards either side of the main dashboard and the one in the boot and all were ok. I guess that I will have to just wait to see what Audi can find

[Peter D]

Yep that has the Energy management control unit which I think is you problem. Regards Peter

[Bloobat]

Got the A6 back from Basingstoke Audi just after Christmas - turned out to need a new ECU (part of steering column). Cost £827.31 + VAT but to be fair to Basingstoke Audi they put in a lot of time & effort and didn't charge me for all the labour or ECU's they replaced but found weren't the problem. They did a full service (£200.08 + VAT) + front pads & discs (£187.69 + VAT) whilst they had it (negotiated prices) so all in all reasonablly happy. I would certainly recommend them as they were cheaper that an Audi Independant garage that I normally use Well worth negotiating with Audi main dealers these days as they will normally beat other quotes......