adamparkinson

I have a 2012 Audi S4,i was gone for a few months and came back to a dead battery. I replaced it with an OEM battery from Audi ( I put it in myself so i did not do any adaptations or anything). And as soon as the car started up the sports diff fault light came on. I have no other issues and its seems to drive normally.

Prior to me leaving i had no issues with the Sports Diff.

Are their extra steps that i need to do?

togatown

Sounds like the car management system still thinks the battery is dead. Do you have a Vag-com cable to run a scan with and then reset any fault codes, and/or to code the new battery?

adamparkinson

Unfortunately I do not. There are no other problems with the car. I can select the different modes i.e sport etc... and it does not seem like there are any problems. I have scheduled maintenance tomorrow anyway... Ill see what their scan reveals. I am hoping the car just thinks a new diff was installed or something....

togatown

The battery management system can act really screwy especially if it goes completely dead. Should be an easy dealer reset while you are there.

adamparkinson

Well it looks like they are saying the whole differential needs replacing. The funny thing is that it was replaced at 28k miles (only 60k on it) and the car sat for 6 months (which is why the battery died) and it wasnt until i put a new battery in that this all started happening. The replaced one of the P/T sensors on it and the fault went away but then came back in... and therefore they whole thing needs replaced... they are asking for $7900 including labor.... I cant imagine the differential just up and failed when the car wasnt driven.... that does not make any sense to me!

I am not sure what my options are.... I dont notice any difference while driving it.

adamparkinson

It blows my mind that this is the second one in 60k miles.... no more audi i guess

adamparkinson

Now the fault appears to be intermittent. They did not flash the ECU so it still had the APR Tune when they did the Pressure sensor replacement procedure... I am not sure what the battery dying... the tune on the ECU and this fault have in common but i have to believe that Diff didnt suddenly go bad after sitting for 6 months. It looks to be a coding or electrical issue. I am thinking about buying a VAGCOM reader... any one have a brand or model that they prefer? I have seen some bluetooth ones on Amazon...

adamparkinson

I isolated the issue to some corrosion on the wiring harness that terminates in the battery well. After i cleaned off the battery ground wire and the remaining connections it cleared the fault and never showed up again. I suggest if you have no leaks in your sports diff that you do that before taking it to the dealer. Dealer was going to charge me 8k for a new sports diff and had not even checked the signal wiring.

huskyz

Wow! I would write Audi a letter. (Though I doubt they'll do anything more than send a "we're sorry" form letter.)

This is ridiculous

UKS4APR1

WOW! (2) That was most likely the problem with the first diff.
Shocking, spend all that money, when it was a corroded electrical connection.
I wonder how often this sort of thing goes on