I recently had a new compresser pump fitted to my audi s8 56 plate . After 8 weeks the pump is kicking in on short trips. I returned to the garage and after having my car for a week they concluded it had a faulty sensor which is part of the valve block. After replacing that my pump is still kicking in. Relay was replaced and everything was tested for leaks.. no faults showing up on diagnostics. Garage is baffled and so am I. Anyone out there had a similar problem

 

What do you mean the pump is kicking in on short trips? If you mean the pump runs when you start driving the car then it is working properly. When you get out of the car and lock it the system notices the car is to high because you have removed your weight from the car. It bleeds off some air. You can hear it do this. Then when you get back in and start driving it has to add air to bring the ride height back up.

 

Leaks may often no codes FWIW. Also may be impossible to leak test a strut adequately unless removed and put in a tub of water with some basic pressure. Simple check to get around this is leave it parked for an extended period when ever possible--may be a few days. See if it is dropped. If slow you may need to measure to fender edge as a reference point.

Said another way, codes can help for things like the air block solenoid issues, but may not for basic leakage. One of those handful of areas on the car where even though there are electronics and sensors, it may not generate fault codes. But it does for other elements that can make you think it has codes for everything. Thus it does have codes for things like an overheated pump (often an indirect leak symptom), valve block solenoids and the height sensors. I saw it on my own car --I have the VCDS code reading cable and software, it leaked down over a day or so, and no codes. Faulty air strut and 100% functioning immediately after replacement.

 

tI understand what you are saying g but rhe pump comes on 3 or 4 rims over a distance of a mile or 2. That's with the suspension set on comfort. I've been to 3 garages and thy said it's not normal and it must have a leak somewhere

 

If you had a leak that causes the compressor to run that often, your car would drop overnight, the yellow and green lift lights would come on at startup, and you'd have DTC's like this:

01583 - Leak in System Detected
000 - -
Freeze Frame:
Fault Status: 11100000
Fault Priority: 3
Fault Frequency: 15
Reset counter: 220
Mileage: 117788 km
Time Indication: 0
Date: 2015.11.09
Time: 14:05:14

01400 - Suspension Level Control
002 - Lower Limit Exceeded - Intermittent
Freeze Frame:
Fault Status: 00100010
Fault Priority: 2
Fault Frequency: 2
Reset counter: 4
Mileage: 117965 km
Time Indication: 0
Date: 2015.12.02
Time: 12:53:02

01577 - Turn-Off due to Over-Temp
001 - Upper Limit Exceeded - Intermittent
Freeze Frame:
Fault Status: 00100001
Fault Priority: 4
Fault Frequency: 2
Reset counter: 4
Mileage: 117971 km
Time Indication: 0
Date: 2015.12.17
Time: 12:28:01

 

Check this tread:

https://www.audiworld.com/forums/a8-...-leak-2894405/