PaulWaterloo

My 01 S8 with RNS-E, bluetooth and MFSW was at a repair facility earlier this week for an oil change and a control arm change.

The battery WAS NOT disconnected. However, when I drove away, the radio was off, once I got a few blocks away, I turned it on and found it in SAFE mode. The instrument cluster also did not have the date/time correct, so I figured the battery did get disconnected.

After I got home and put the code in the RNS-E, it worked, but no longer had a CAN signal. It was pretty obvious as it would not turn on/off with the ignition and had no back lights on with the headlights on. The bluetooth was not communicating with it and the MFSW did not have lights on with the headlights on.

After a call to the shop, they said the car was up on the lift with the keys in the ignition for almost a day, they stated that the ignition was off, but obviously something was on. When they went to start the car, it started "slow", which I believe to be like a very cold start with a degraded battery in the winter. It caught and started, it was never jumped. So the voltage dropped quite a bit during the start event.

A few modules had a low voltage intermittent fault code, cleared those, and got the following instrument cluster fault code, it returns as soon as you clear it:



Address 17: Instruments Labels: 4D0-919-033-MYX.lbl
Control Module Part Number: 4D0 919 035 AT
Component and/or Version: KOMBI+WEGFAHRS.VDO D35
Software Coding: 02283
Work Shop Code: WSC 23132
Additional Info: WAUGU54DX1N012848 AUZ7Z0A1817400
3 Faults Found:

01300 - Control Module for Navigation with CD-Rom (J401)
49-00 - No Communications
01303 - Telephone Transceiver (R36)
49-00 - No Communications
01304 - Radio
49-00 - No Communications

If I got to channel 140, here's what I get:



There was no work done to the interior of the car, I do not feel there is any "new" wiring issues, but just need to somehow reset the system. I have reset the RNS-E and checked everything via vag-com, it all looks good.

What should I do? Try disconnecting the battery for 15 minutes?

FYI, this is an 01 S8 that I had to add the CAN wires to the IC, and all three of these components are in that "downstream" area for the CAN wiring as I retrofitted all of them.

Thanks.

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PaulW
01 S8

PaulWaterloo

Figured it out, ended up disconnecting the battery for 15 minutes, reconnecting it. The backlight of the RNS-E did not work until after I unlocked it with the code. Now it has CAN communication again.

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PaulW
01 S8

PetrolDave

Maybe with the lower voltage due to the battery being in a discharged state the signal level on the CAN bus is insufficient?

Did they have a door, bonnet (hood) or boot (trunk) open while it was on thelift which may have left a light on and been discharging the battery?

How old is your battery? I'm wondering if your battery is old and the period of discharge has "taken it over the edge"?

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06 RS4 Avant - Phantom Black

2010 EU RNS-E 8P0 035 193 C with A4 faceplate - with SDS (HW 070, SW 0150) - coded 309723
16GB SDHC card + CD changer and AMI ready to be fitted

BT 8P0 862 335 M - coded 10702 paired with HTC TyTN II (WM6.1)

Instruments ch 62 = 23
VCDS (VAG-COM) 908 + HEX-COM+CAN

PaulWaterloo

Dave, thanks for the response. I have no idea how the battery discharged, and I will never know. The battery is original, but it's in perfect shape. Disconnecting and reconnect it did the trick. All is good.

But in the end, a very frustrating experience. I guess I am back to fixing my own car on my own time. Previously, I had the car detailed, the guy who did it used "engine cover dressing" on the engine compartment parts, it dripped down the transmission control wire, to the F125 transmission control switch, and trashed it. The guy called and said "did you know your car doesn't go into reverse"......6 hours of troubleshooting later and replacement of the $300 switch got me going again.

Is it just me or do these things normally happen when you bring your car in for repair? They don't when I do it myself.

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PaulW
01 S8

PetrolDave

A 9 year old battery is well past it's expected end of life - even the best "premium" batteries only come with a 5 year warranty.

As owners we always take more care of our own vehicle than we can expect a tradesman to.

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06 RS4 Avant - Phantom Black

2010 EU RNS-E 8P0 035 193 C with A4 faceplate - with SDS (HW 070, SW 0150) - coded 309723
16GB SDHC card + CD changer and AMI ready to be fitted

BT 8P0 862 335 M - coded 10702 paired with HTC TyTN II (WM6.1)

Instruments ch 62 = 23
VCDS (VAG-COM) 908 + HEX-COM+CAN

PaulWaterloo

I still don't think the life of the battery is the issue, the issue was that it was discharged and had enough to start the car and drop the voltage to some threshold that tripped the event.

The A8/S8 battery is located in the trunk, is absolutely huge and I believe this is one reason why it lasts so long, doesn't get cooked in the summer or frozen in the winter. My car has also been garaged its whole life.

Don't jinx me!!!!

Cheers!

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PaulW
01 S8

PetrolDave

I'm going to disagree with you that the battery isn't an issue - a week of standing still would not have had that effect on a battery in good condition.

BTW the battery on the RS4 is in the trunk (boot) also. Mine's now 4 years old and I don't expect it to last much more than another year or so - IMHO it's going to let me down either this coming winter or the one after.

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06 RS4 Avant - Phantom Black

2010 EU RNS-E 8P0 035 193 C with A4 faceplate - with SDS (HW 070, SW 0150) - coded 309723
16GB SDHC card + CD changer and AMI ready to be fitted

BT 8P0 862 335 M - coded 10702 paired with HTC TyTN II (WM6.1)

Instruments ch 62 = 23
VCDS (VAG-COM) 908 + HEX-COM+CAN