2004 A3 3.2 Quattro instrument cluster randomly losing power

[WrightClick]

Hiya,

Six week lurker, first time poster here!

I recently bought a 2004 A3 3.2 Quattro and it came with a load of little electrical gremlins which the seller forgot / failed to mention. With some assistance from a £27 fault code reader and a local VAG specialist with VCDS, I've sorted most of them. However, there's one left...

The instrument cluster randomly loses power, which resets the clock to 00:00 and the date to something usually a day or two previous. I haven't quite worked out the pattern with the date yet. Anyway, it did it while I was driving along the other day. The whole cluster went blank, then it reset itself and carried on fine. It's the first and only time I'd actually seen it happen, as I usually notice it when I get in the car after it's been parked at work or overnight, when the time is wrong.

I've just done a scan and my code reader is showing 00474 Control Module for Immobilizer sporadic 004-No Signal/Communication on the CAN Gateway. I've also seen fault codes logged by the auto transmission and the central convenience module, relating to implausible signals and/or intermittent comms to the instrument cluster.

It's got a brand new 80Ah battery (previous owner had put a new one in, only 70Ah, which is undersized for this model), so it's not that.

I took the cluster out on Friday and bashed it about while it was on, to see if it was a dry joint or bad connection somewhere and that didn't show anything up. I applied some special contact treatment which we have at work (electronics design/manufacture) to the connector, but this hasn't helped either.

Has anybody got any bright ideas?

Cheers,

Rich

 

[Marek196c]

I would call seller and tell him to sort it out for you (specially if you got copy of auction/listing) as was intentionally (or not) hiding the problems with the car. As well better always get some mechanic with you and obd2 scanner.

 

[WrightClick]

At the end of the day, it's a 13 year old car and a private sale, so little problems are to be expected. For the price I paid, I don't think I got a bad deal, even if I have to spend a bit of time and money sorting these things out.

 

[Marek196c]

but still he should tell you that he don't know or that there's a fault TBH, when I'm selling ny stuff always trying TBH as possible and expect that from others.

 

[WrightClick]

Yeah, I dunno. He may have just thought it was one of those things. I appreciate your thoughts, but I'm looking for advice on fixing it rather than taking it back.

 

[Marek196c]

Anyway in fact error telling you that is something wrong with immobilizer and not with cluster (also if this gettin shut off and playing) I would start from the key itself, if you got 2 keys try to use 2nd one for a while and see if helps, meanwhile can be the connector on other end (CAN gateway) rather than cluster end. As you said you doing electronics design, check on etka the placement of components so you can see where the plugs going, as well I know that this clusters got internal ROM (storing milleage and some other info) so could be cluster giving up itself, they are all my guesses for now.

 

[WrightClick]

It's showing an immobiliser issue, because the immobiliser control module is integrated into the instrument cluster. I've had other errors too, which all point to the cluster. I did another scan today after it had reset again and I have 01317 Control Module in Instrument Cluster (J285) sporadic 004-No Signal/Communication.

There seem to be a few people who've had this issue on various forums, with no definitive fix. One mentions bad grounds, so I'll check all those when I get some time over the next few days. Other than the cluster itself, I'm not sure what else it could be.

 

[Marek196c]

I see, but don't think it will be bad earth, if not it would get more problems when active rather than when on sleep mode, but still good to check and maybe use a bit of cooper paste on them for better current flow? (I know that on old cars that got bad earth some people was just screwing some wire to earth point closest to underneath of body and let it flow over the asphalt but don't think would help.)

 

[Horlix66]

Check the connectors in the boot, and on the new battery you fitted.

Mine used to do something very similar - it always seemed to happen on clicking the central locking, dash/clocks/stereo etc would all reset. And it happened a couple of times while driving (with fog lights on when switching main-beam on/off seemed to trigger it, exactly the same symtoms as you described)

Anyway It ended up (touch wood coz it hasn't happened since) being a "slightly" loose battery connection in the boot