Shifter Locked Out - Multiple Codes/Symptoms All At Once

[JakeLight]

Driving to scoop up dinner I had these new symptoms:
o PRNDS all highlighted
o Oil Sensor Warning
o AC/Climatronic no power

Car seemed to drive normally (not in limp mode for sure), shifting as expected.

Before I shut the car off trying to move the shifter to Park it locked itself in Neutral and wouldn't move. I was able to shut the car off, put key in the ACC position (the click before 'On') and move it back to park.

New Codes from scans (all new from this symptom):

---------------------------------
Address 01: Engine Labels: 077-907-558-BCY.lbl
Part No: 4D1 907 558
Component: 4.2l V8/5VT G 0002
Coding: 0006752
Shop #: WSC 87119 806 641192
VCID: 6B96DCAB4B21F7D306-5160

2 Faults Found:
18043 - Powertrain Data Bus
P1635 - 008 - Missing Message from A/C Controller
18062 - Please check DTC Memory of Instrument Cluster
P1654 - 004 -
Readiness: 0000 0000

-----------------------------
Address 02: Auto Trans Labels: 01L-927-156.lbl
Part No: 4B0 927 156 FL
Component: AG5 01L 4.2l5VT USA 0305
Coding: 0000002
Shop #: WSC 00000 785 00200
VCID: 76A0FDDF00633A3BE9-5160

2 Faults Found:
18169 - Shift Lock Solenoid (N110)
P1761 - 003 - Short to Ground
18161 - Tiptronic Switch (F189)
P1753 - 003 - Implausible Signal

------------------------------
Address 17: Instruments Labels: 4B0-920-xxx-17.lbl
Part No: 4B0 920 983 D
Component: KOMBI+WEGFAHRS. VDO D13
Coding: 03284
Shop #: WSC 62799
VCID: 291AE6A3D15D25C3B4-5160
WUAPV64B53N904614 AUZ7Z0C2409258

2 Faults Found:
01311 - Information Data Bus
80-00 - Single-Wire Operation
00562 - Sensor for Oil Level/Temperature (G266)
30-00 - Open or Short to Plus

I checked all fuses, found a 15A in position 33 that seemed in dubious shape (top by numbers was distorted from internal changes) so replaced that. Also found one of the smaller 10A fuses in position 5 that was visibly broken as well, so also replaced that. Locations based on this chart:

https://fusesdiagram.com/audi/fuses-and-relay-audi-a6-c5.html

Tested again with new fuses, no change.
Cleared codes, no change.

It feels that based on the large count of things that all happened at the same time I might be hitting a single point of failure but couldn't track down any good info on what (if anything) interconnects those items that are showing shorts (Climatronic, Transmission brake switch N110, Oil Sensor).

Any ideas? Thanks in advance

-jake

[JakeLight]

More codes (scan from 10 days ago 5/2) that I cleared to see if they came back:



Address 01: Engine Labels: 077-907-558-BCY.lbl
Part No SW: 4D1 907 558
Component: 4.2l V8/5VT G 0002
Coding: 0006752
Shop #: WSC 87119 806 641192
VCID: EB99D4AFCF4161978920A3-5160


3 Faults Found:
17863 - Exhaust Gas Temp Sensor 1 (G235)
P1455 - 008 - Implausible Signal - Intermittent


17867 - Exhaust Gas Temp Sensor 2 (G236)
P1459 - 008 - Implausible Signal - Intermittent


18010 - Power Supply Terminal 30
P1602 - 002 - Voltage too Low - Intermittent


Address 06: Seat Mem. Pass Labels: None
Part No SW: 4B0 959 760 C
Component: Sitzmemory R1 BF 0103
Coding: 00003
Shop #: WSC 00000 000
VCID: 2D1D9AB7B1D53CA757D44D-4AE0


1 Fault Found:
00668 - Supply Voltage Terminal 30
07-10 - Signal too Low - Intermittent

--
Address 08: Auto HVAC Labels: 4B0-820-043-MY2.lbl
Part No SW: 4B0 820 043 AR
Component: A6-Klimavollautomat 0208
Coding: 00000
Shop #: WSC 40233 000
VCID: 6A9751AB40BBEB9F72362E-2578


1 Fault Found:
01592 - Air Quality Sensor (G238)
57-00 - Electric Circuit Failure


--
Address 35: Centr. Locks Labels: 4B0-962-258.lbl
Part No SW: 4B0 962 258 M
Component: Central Lock/Alarm D38
Coding: 15885
Shop #: WSC 00000 000
VCID: 33298CCF57F16A5701108B-4F0C


5 Faults Found:
00668 - Supply Voltage Terminal 30
07-00 - Signal too Low
(other 4 faults are cant lock each door intermittent)


Address 36: Seat Mem. Drvr Labels: None
Part No SW: 4B0 959 760 B
Component: Sitzmemory R1 F 0204
Coding: 00001
Shop #: WSC 00000 000
VCID: 2C1B97B38ACF35AF40AA58-4AE0


1 Fault Found:
00668 - Supply Voltage Terminal 30
07-10 - Signal too Low - Intermittent

The in-cabin filter was recently replaced, wonder if something around that got nudged that wasn't supposed to be...

[NerdyDeeds]

There are a bunch of grounds on the firewall, with some being near by the cabin filter. Sounds like a bad ground or loose connection somewhere.

One set of ground points is on the firewall behind the drivers side of the engine. Otherwise pull the rain tray off and look for any corrosion and push in each connector.

[hahnmgh63]

Any work done on the car recently? How old is the battery?

[JakeLight]

New battery was put in early March (self-inflicted damage caused by leaving dash-cam plugged in for many days)

Full suspension replacement (Koni setup) was done recently (finished early April), all control arms (12), lower engine cover added (was not present when I got it), Hotchkis swaybar added, engine air filters, cabin air filter, oil change + oil filter

The G238 code was not present before the cabin filter was replaced, so definitely going to look into that area

Also fuse 5 pops every time the key provides power

[hahnmgh63]

Items on Fuse 5:
Oil level/oil temperature sender
Compressor regulating valve, air conditioning system
High pressure sender
Tiptronic switch
Tyre pressure monitor control unit
Bulb monitoring device
Mobile phone operating electronics control unit
Control and display unit for air conditioner/Climatronic
Air quality sensor
Navigation system with CD drive control unit
Self-levelling suspension control unit
Operating unit to control suspension height
Telephone/telematics control unit
Control unit for voice control
Parking aid control unit
Rear roller blind switch

Obviously if you don't have the roller blind it isn't on the circuit as well as N. American cars never had TPMS or self-leveling suspension.

[JakeLight]

Going to open this suspiciously bent taped up bit tomorrow and see what's what, I wonder if this is where power for the K40 was spliced in. This is right next to the purge valve.

https://www.rs6.com/attachment.php?attachmentid=19439&stc=1

-jake

[JakeLight]

Is there an RS6 specific wiring diagram out there - the AllData site doesn't have one specific to this car. Have unplugged everything we think is on that fuse but it's still popping when turning the key.

Also fwiw found a shifter lockout workaround per this youtube video that works, so can at least drive the car now (basically remove trim surround at shifter, then straight down at the Front-Left of the shifter there is a white plastic bit that you can push forward to unlock the shifter lock):
https://www.youtube.com/watch?v=j0r7oKRpBv4

[JakeLight]

Just thought of another thing that is maybe related to the fuse blowing, back when I first got the RS6 in mid-2019 I gave a few people rides and when someone sat in the rear passenger side I would occasionally get an airbag light. Since I see 'SRS Warning Lamp' on that Fuse 5 I'm wondering if this might somehow tie in. I did work sitting on that seat in the down position to replace the battery a couple of months back. Car is at an indy shop being looked over, but still unsolved as of this moment...

Here's the code when I pulled it back on 8/9/2019


Address 15: Airbags Labels: 4B0-959-655-AI84.lbl
Part No: 4B0 959 655 Q
Component: Airbag 8.4EP 2001
Coding: 0000607
Shop #: WSC 00000 785 00200
VCID: 3E3025FF68D3B2BFAB-5184

1 Fault Found:
01212 - Belt Tensioner Igniter; Rear Passenger Side (N197)
001 - Upper Limit Exceeded - Intermittent

[Muggy]

Interesting about the airbag light when sitting in back...I had a Merc E320 a while back and it had a notorious intermittent battery drain issue...turns out the wire for the driver's door lower interior light ran down underneath of the dead pedal...basically, pressure on the dead pedal would only occasionally cause it to ground out through a chafed wire and cause only the lower door light to stay on that you couldn't see because it was up next to the seat with the door closed. Long story short, hidden wires under carpeting and seats can be an issue!

[JakeLight]

Just got word the shop located the issue, it was tied to the wiring related to the air quality sensor after all, something inadvertently got pinched on re-assembly it sounds like. Picking up later today :rs6kiss:

-j