A6 S-Line C7 Electrical & Gearbox issues... Please help.

[Fionn27]

Hi Guys,
I'm after some advice on my 2014 Audi A6, C7, Ultra S-line, Black edition Avant (pre face lift) please:
Following a very minor bump i've been having lots of different issues.
The towing company brought my car to my house but the battery was flat when it arrived here after a few days at their yard.
They jump started it using a booster pack when it arrived here and now I have a ton of issues. The major one being that the car now won't engage a gear, it registeres on the dash that a gear is selected however the engine just revs and the auto box wont engage at all in any gear.

I disconnected and charged the battery up fully two days ago and it seems to be holding a charge fine. it starts and runs however I worry that them jumping it may have caused some issues... The dash now shows on start up the following messages / errors:

- "Gearbox Malfunction No reverse gear (you can contunue driving)"
-"Gearbox Malfunction: you can continue driving (Limited functionality)"
- "Caution Vehicle Parked Too Steep" my driveway is flat and the handbrake light is constantly flashing.
- "Start- Stop System fault. Function Unavailable"
- "Stabilisation Control (ESC) Fault! See owners mannual"
- "Tire Pressure System Fault!"
- "Particulate filter: system fault. see owners mannual. "
- "Audi Adaptive Light system fault."
- "Parking brake"

Warning Lights on the dash:
- Handbrake light constantly flashing (P). / red
- ESC light iluminated / yellow
- Check engine light / yellow
- Tyre pressure / yellow
- Glow plug light constantly flashing / yellow
- exclamation mark iluminated / yellow

Last night the running lights also randomly came on on the car and I was not able to turn them off without getting in and starting it. Also If i lock the car the allarm will go off within a minute or so.
It's all just very odd and im struggling to understand whats going on.

If anyone is able to shed some light on what may be happening or know a good auto electrical engineer in the bromsgrove / stourbridge / halesowen area that's able to run a mobile diagnostic (as the car is stuck in my driveway). I'd massiveley appreciate any sugestions.

 

[RAF_S7]

A VCDS scan will go somewhat to finding out what's going go here. If you click on the VCDS Map tab at the top of the page, you should be able to find someone local to you.

Low battery voltages can cause a myriad of problems on the C7/7.5 platform. Have you checked the actual battery voltage with a meter, after you have charged it?

 

[Fionn27]

Hi, Thank you for your reply.
No, I havent checked the voltage with a metre.
I'll go buy myself one and go from there hopefully that'll determine if i need a new battery or a VCDS scan (or both).

Thank you.

 

[RAF_S7]

You may find that some fault codes can only be cleared using VCDS - they won’t go away with a simple ignition turn off-on.

 

[Fionn27]

The battery looks to be fine.
Checked all fuses, and have done a factory reset with no joy.
I'm now after someone whos mobile that could come to do a VCDS Scan for me to figure out if its the mechatronic control unitor something else.

Any recomendations of someone South Birmingham / North Worcstershire area thst could help with a Scan?

 

[RAF_S7]

What was your measured battery voltage?

Check here for your nearest VCDS User (click on marker to bring up info, then message direct)

Note that you may struggle with current Pandemic restrictions.

 

[BahnStormer77]

If you can't get access to somebody with VCDS and you only need something for this bit of error diagnosis, then you can get an ELM327 OBD2 dongle (will pair with any Android device) and then the TorquePro software. I paid ~£5 for the dongle on Amazon next day delivery and £4 for TorquePro.

That will allow you to read the error codes and also to clear any that are only out due to a temporary situation - e.g. the way it was towed.

VCDS is the tool you'll need to recoding any features on the car, but you might get away with a simple dongle as a quick fix (I have both and 90% of the time, the dongle does the job for quick error diagnosis).

In terms of the error you're seeing - until you've cleared the errors that you're seeing, I suspect a lot of those will be false alarms or easily explainable - in order of least to most (potentially) serious.

1-"Start- Stop System fault. Function Unavailable"
This is normal after you run the battery right down - get one of those trickle chargers with a "reconditioning" feature and I think you'll be fine!

2- "Stabilisation Control (ESC) Fault! See owners mannual"
3- "Tire Pressure System Fault!"
I would be pretty certain these two are false alarms related to wheels turning at unexpected rates. Likely they won't come back unless the bump was hard enough to actually shift the suspension / wheel alignment.

4- "Caution Vehicle Parked Too Steep" my driveway is flat and the handbrake light is constantly flashing.
5 - "Parking brake-
POSSIBLY also the same - due to towing? Or the parking brake may have been damaged if it was enabled while towing?

6- "Particulate filter: system fault. see owners manual. "
7- "Audi Adaptive Light system fault."
Absolutely no idea what could have triggered those - seem to be really disparate systems. Was the windscreen/dash area damaged at all? (pretty sure the adaptive light sensor is behind the rear view mirror). They might clear after you clear all the error codes.

8- "Gearbox Malfunction No reverse gear (you can continue driving)"
9-"Gearbox Malfunction: you can continue driving (Limited functionality)"
I'm assuming you have the 7 speed DSG, not the 8 speed ZF?
I really hope this is also a temporary glitch due to towing, but when the error happens, is it IMMEDIATE or is it only just after you pull off?
I had this, where the car would pull off fine, but as soon as the gearbox attempted to 2nd switch to the other half of the gearbox (2,4,6,R), it would "clunk" and then I'd get this error. The only way of selecting reverse was to power off, select reverse immediately and then it was fine.... the failure was due to the "mechatronic unit" that switches between the two halves of the gearbox. I was able to drive the car home, but only by keeping it in "sport" and allowing it to switch from 1st to 3rd/5th/7th. Be warned though - I read up on it afterwards and there was a safety recall on the DSG gearboxes due to this issue because the mechatronic failure manifests in various ways: locked in 1/3/5/7, locked in 2/4/6/R or in very rare cases, entire transmission locked up.... with one S4 having this happen in the middle of a highway where all 4 wheels locked up and slid. I would not advise driving the car too much in case this happens!
Apparently it was a common failure on the earlier DSG's (up to ~2013/2014) and it would normally happen to cars around 30k-60k miles.
Mine was just the "1/3/5/7 error", but was several years ago: 3 days after my 3 year warranty ran out and the car was only on ~8k miles... fortunately my local Audi comp'd the whole of the repair bill* and the whole episode only cost me ~£15 for the courtesy car insurance (for ~2 weeks).

*not trying to be alarmist and the reason I said I hoped it was just the towing/jump start, but for mine it was a gearbox rebuild and replaced it with the re-designed mechatronic units, which apparently normally costs >£2k in labour alone.