Have the following codes which clear but eventually come back. Can't actually see anything wrong with the car! Any ideas anyone? If I clear the instruments fault it clears the CAN gateway code too, is that expected?

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Address 08: Auto HVAC Labels: 3U0-907-044.LBL

Controller: 3U0 907 044 A

Component: CLIMATRONIC S B5 C 2004

Coding: 17000

Shop #: WSC 00028

VCID: 3115B828E827

1 Fault Found:

01341 - Control Module in Instrument Panel On Comfort CAN (J285)

27-00 - Implausible Signal

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Address 17: Instruments Labels: 3U0-920-xxx-17.LBL

Controller: 3U0 920 941 A

Component: KOMBI+WEGFAHRSP VDO V06

Coding: 31415

Shop #: WSC 00000

VCID: 3217B724ED21

TMBBU63U969103632 SKZ7Z0E3029433

1 Fault Found:

01336 - Data Bus for Comfort System

49-10 - No Communications - Intermittent

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Address 19: CAN Gateway Labels: 6N0-909-901-19.LBL

Controller: 6N0 909 901

Component: Gateway K<->CAN 0001

Coding: 00006

Shop #: WSC 00028

VCID: F093FD2CA3AD

1 Fault Found:

01336 - Data Bus for Comfort System

49-10 - No Communications - Intermittent

Anyone?

Not a superb expert, is your passenger footwell dry? Could be the start of the dreaded water ingress into the comfort control system in the passenger footwell

Not a superb expert, is your passenger footwell dry? Could be the start of the dreaded water ingress into the comfort control system in the passenger footwell

Yes it is, there was the beginning of a tiny dribble coming in but I've replaced the seal now and no ingress.

It seems like all the faults I have are in the air conditioning / CAN gateway / instrument area, and none of the tell-tail interior light / alarm / etc issues from water ingress. I would have guessed it might be a fault with one of the 3 suspects above, but I don't want to try replacing them blindly - hoping someone else has seen these faults and fixed them.

If I clear them they go, but a week or so later I look and they'll usually be back.

There is as far as I can tell nothing wrong with the car. I've seen occasionally the weird German satnav error in the instruments display on starting the car, but that always goes from cycling the function on the display.

Edited 4 February, 201214 yr by jimbof

Check for corrosion on any wires

Check for corrosion on any wires

I'll get it out and give it a going over again, but couldn't see anything last time. Though as I say it does seem more local to the dash area.

I pretty much ignore all intermittent faults.... Its usually little voltage fluctuations that bring them up. I only start paying attention if the same culprits keep appearing time after time once cleared.

I wonder if low voltage related - the cr has been a little slow starting these cold days - perhaps battery is getting tired? It is a Bosch S4 but i don't know how old it is...

All related to the CCM.

You say you've fixed the ingress problem but keep a careful on the state of the wire nodes around the CCM, they are still prone to corrosion even from damp conditions in the carpet.

All related to the CCM.

You say you've fixed the ingress problem but keep a careful on the state of the wire nodes around the CCM, they are still prone to corrosion even from damp conditions in the carpet.

Thanks I'm going to give it another look. There was barely anything coming in though. It seems all these faults are related to convenience CAN bus failure - but nothing breaks - so I guess this probably means that the CAN bus is intermittently switching into 1-wire mode, either because of a damaged CAN bus wire / connection or a faulty / failing device on the CAN bus. So how does manipulating the wiring while watching the CAN bus status in VCDS measuring blocks for the AC controller sound? Is it likely to change fast enough to catch it? Is there any way to set a "trigger" like you would with an oscilloscope to trap a trace of it going from 2-wire to 1-wire?