Before I do battle with the dealership, is it acceptable for the air suspension to drop over, say, a week and if so what's acceptable?

Originally reported the the front air suspension was on the bump stops after 7 days and the rears had dropped as well.

Dealership changed the front right suspension unit (why they can't use nearside and offside I don't know) 

Put the car in quarantine for a week and visually it appeared to have dropped so before unlocking and getting in the car I took the following measurements:

Front OS – 704mm

Front NS – 695mm

Rear OS – 732mm

Rear NS – 710mm

 

After I started the car they changed to:

Front OS – 722mm

Front NS – 729mm

Rear OS – 729mm

Rear NS – 721mm

It's defiantly better than it was but still dropping

What are peoples thoughts on cause and levels (if any) of acceptable drop over time.

Up until Sept 2023 (2 1/2 years old) it hadn't dropped at all when left.

TAI

 

Shouldn't be dropping to the floor. It needs a diagnostic check to see if any fault codes flag up but does sound like a leaking suspension airbag. 

Front NSF drop is excessive and the other ride height changes could be attributed to that.  NSF is down and OSR has gone up. OSF and NSR slightly down but could be caused by NSF being so low just like a puncture would. You said front right had been changed so front left failing now would be logical 

2 hours ago, Steve Q said:

Shouldn't be dropping to the floor. It needs a diagnostic check to see if any fault codes flag up but does sound like a leaking suspension airbag. 

Steve, cheers for the feedback.

No messages unless it's on the desk at which point it reports a "Sports differntail Fault" and an "Air suspension: vehicle currently too low"  and a C11E2F1 and a couple of U122B00 messages.

If the suspension just drops a bit then nothing so I agree an airbag or possibly an air suspension controller that has a leek??

46 minutes ago, Sid2020 said:

Front NSF drop is excessive and the other ride height changes could be attributed to that.  NSF is down and OSR has gone up. OSF and NSR slightly down but could be caused by NSF being so low just like a puncture would. You said front right had been changed so front left failing now would be logical 

Agreed, cheers

1 hour ago, K200CWC said:

Steve, cheers for the feedback.

No messages unless it's on the desk at which point it reports a "Sports differntail Fault" and an "Air suspension: vehicle currently too low"  and a C11E2F1 and a couple of U122B00 messages.

If the suspension just drops a bit then nothing so I agree an airbag or possibly an air suspension controller that has a leek??

The car itself has detected a leak so if definitely say it's the bag. If non were working then that'd be more likely the compressor but thankfully not in this case. 

Sorry for the delay in updating, front NS suspension unit replaced but the car is still dropping on all four corners, roughly 10mm on both fronts and 6mm on both rears after 6 days of being parked up; is this acceptable? 

On 4/7/2025 at 11:59 AM, K200CWC said:

Sorry for the delay in updating, front NS suspension unit replaced but the car is still dropping on all four corners, roughly 10mm on both fronts and 6mm on both rears after 6 days of being parked up; is this acceptable? 

Sorry for the delayed reply, did you get this sorted? Not sure it should be dropping after 6 days. I'd definitely say it's a leaking bag.  

1 minute ago, Steve Q said:

Sorry for the delayed reply, did you get this sorted? Not sure it should be dropping after 6 days. I'd definitely say it's a leaking bag.  

Appears to be sorted but looking for a C8 specialist once the warranty expires as I've lost total confidence with the main dealer customer services management.  I found a dealer with decent customer servers but as soon as they had to escalate for clearance I encountered feedback from someone who shouldn't be in this type of roll.

I still have lots CAN bus communications errors but can't get Audi to do anything about them, TADS (they all do that sir) but I work in data communications and don't agree.  It's either poor module firmware or a loose fibre/copper connection.  If I had access to the schematics and module / connections location I'd go through it myself once out of warranty but I cant find these anywhere.  

Cheers for the chase.

Sorry to hear you're still having issues. Keep fighting because they'd love to charge you for the work if it was out of warranty! 

Hello Charles,

If this were mine, I would be seeking advice on your air suspension issue from BagpipingAndy ( obviously up your neck of the woods). He is the guru on these systems, and may well have come across this before with this model. You will find him on EBay. Try searching ‘air suspension compressor piston ring’ or similar.

Please let us know how you get on. 
Regards,

Gareth. 

did you get this resolved? 

My 50tdi has a suspension low message and the local garage found that the ecus werent talking which I assume are can bus errors.

I don't want to type the word begging with Y as I'll get bitten!

After the dealership got 'the tool' from Audi for the 3rd / 4th time to plug into the suspension it's had both front suspension units replaced (I think it only needed one but OS was swapped first and NS when the fault came back within 48h), a controller and some software updates and so far so good.

Major issue was the dealership getting hold of 'the tool' as it appeared to take 3-9 weeks to get hold of from Audi UK.