Air suspension flukey
08-03-2017, 11:03 PM
#11
AudiWorld Member
In the crank chamber there is no air pressure! This is the suction area. Usually when there is leakage of air pressure, the dryer inside the compressor is filled with water. Check it. I am convinced that there are massive air leaks in the system and the compressor can not fill the missing. This is why the compressor with wear is high in the first place 
Last edited by amiram; 08-03-2017 at 11:17 PM.
08-04-2017, 08:02 PM
#12
Tried resealing the side plate of the compressor but I still feel a constant flow of air escaping from the edges of the plate when it runs. The compressor runs but cuts out when it gets to the overheat point. The the car won't raise beyond level 1 but seems to be holding. I know I need to get a hold of a scanner cable to see if there and codes that show up. I did replace the dryer media in the compressor and the was a small amount of moisture inside but not a lot.
08-05-2017, 08:29 AM
#13
AudiWorld Member
Ensure that the compressor can raise air pressure up to 16 bar. The air blowing thet you feel at the side plate. This happens when the piston goes down and pushing the air backwards. the side plate is flexible. Basically like a one-way valve. This is not your problem
Last edited by amiram; 08-05-2017 at 08:32 AM.
08-11-2017, 01:01 AM
#14
Leak from the airpipes between the bag and valveblock is very uncommon.
Also leak at the airpipe connector at the valveblock side.
Most often leaks and reasons
Fittings:
A. O-ring seals (upper, bottom) - often! Improper mounting and/or using the old ones. Further, e.g. installing twisted and/or without silikon grease. - Slow loss of air. Quick loss in cold weather (shrinking)
B. airpipe connector at airbag: improper mount, mostly. Especially: the sleeve torn in - Arnott specific problem with the black plastic upper part. - Slow air loss.
Air bag:
C. The classical cracks in the rubber material as commonly known... after 2 years it is quite common, hence, within 1 year also, at the chinese ones...
- Slow / quick air loss.
D. Leak at the steel collar. That is manufacturing failure. For me it was an Arnott-specific problem in 2013. The car lost 1-2cm height in 24 hours on the front but not more. A half level or almost a whole level (with thermodrift). It was changed under warranty.
- Slow air loss.
Also leak at the airpipe connector at the valveblock side.
Most often leaks and reasons
Fittings:
A. O-ring seals (upper, bottom) - often! Improper mounting and/or using the old ones. Further, e.g. installing twisted and/or without silikon grease. - Slow loss of air. Quick loss in cold weather (shrinking)
B. airpipe connector at airbag: improper mount, mostly. Especially: the sleeve torn in - Arnott specific problem with the black plastic upper part. - Slow air loss.
Air bag:
C. The classical cracks in the rubber material as commonly known... after 2 years it is quite common, hence, within 1 year also, at the chinese ones...
- Slow / quick air loss.
D. Leak at the steel collar. That is manufacturing failure. For me it was an Arnott-specific problem in 2013. The car lost 1-2cm height in 24 hours on the front but not more. A half level or almost a whole level (with thermodrift). It was changed under warranty.
- Slow air loss.
I replaced the air springs myself with Chinese items direct from Aliexpress but now upon reading the above I'm wondering how long my "fix" will in fact last... Well I suppose it's not the end of the world as I know how to change them now so maybe I just need to be prepared to do it again in a few years?
I've also replaced my air compressor piston ring with good results so far, but upon reading this thread I note that this might also be a temporary fix. I'm starting to wonder if a standard C6 rather than an allroad might've been a better solution for me!
08-11-2017, 05:13 PM
#15
Suspension is working but not quite 100%.
I installed a new compressor, cleared all the codes. The car raises to L3 but a bit slowly. Will not go to 4. Seems to be holding well at L2 which is what I normally drive it at.
A few strange noises as it reaches L2 and then L3. As soon as it reaches the selected level there's a bit of a thump as the compressor stops. Almost like valve shutting loudly. Never heard that previously.
As long as it holds at L2 I'm ok with that for the short term, but I do want to find out what's keeping the suspension from performing 100%
I installed a new compressor, cleared all the codes. The car raises to L3 but a bit slowly. Will not go to 4. Seems to be holding well at L2 which is what I normally drive it at.
A few strange noises as it reaches L2 and then L3. As soon as it reaches the selected level there's a bit of a thump as the compressor stops. Almost like valve shutting loudly. Never heard that previously.
As long as it holds at L2 I'm ok with that for the short term, but I do want to find out what's keeping the suspension from performing 100%
08-21-2017, 06:53 AM
#17
Suspension held for a week with no codes till 2 days ago. After driving a short distance the suspension error light lit up solid. I parked for 30 minutes and came back to see that the rear suspension had dropped to below L1 position, but the fronts were fine — the rears have never dropped separately, only the fronts or both front and back together.
I scanned the codes and came up with Upper Limit Exceeded, and 01772 - Signal from Level Control Pressure Sensor (G291) 27-10 - Implausible Signal - Intermittent. I was able to clear the codes and raise the suspension back up to L2. The car was fine for a day.
Then last night again after a 2 hour drive and then slowing down for stop and go traffic, I got the flashing yellow suspension dash light. The suspension dropped from L2 to L1 and then the held for another half hour of traffic. The yellow suspension then light lit solid. Strange thing was that when the suspension dropped to L1, the UP button on the level control buttons was blinking as if I had had pushed it, which I hadn't. Also there are times when the suspension has read at L1 when it's actually at L2.
This morning I scanned the codes and again came up with 01577 - Turn-Off due to Over-Temp: Upper Limit Exceeded, and 01772 - Signal from Level Control Pressure Sensor (G291) 27-10 - Implausible Signal - Intermittent. I was able to clear the codes and raise the suspension back up to L2.
As I mentioned earlier, I replaced the front air bags a year ago with Arnott Gen I's and last week I replaced the compressor. I have fastidiously tested for leaks with soapy water and tightened connections everywhere I can get to. I once received the 01772 code indicating that the harness that feeds the level control pressure sensor has an intermittent short on it's 12V positive wire.
Hate just throwing parts at the problem without know exactly what it is. But with all these variations it's been hard to nail down exactly where the problem is. Thinking it could very well be the valve block/pressure sensor is shot as there seem to be so many variables. I haven't tried testing the tank for a Bar measurement, but with a new compressor in place there should be proper pressure.
Thanks for everyone's input on this problem.
I scanned the codes and came up with Upper Limit Exceeded, and 01772 - Signal from Level Control Pressure Sensor (G291) 27-10 - Implausible Signal - Intermittent. I was able to clear the codes and raise the suspension back up to L2. The car was fine for a day.
Then last night again after a 2 hour drive and then slowing down for stop and go traffic, I got the flashing yellow suspension dash light. The suspension dropped from L2 to L1 and then the held for another half hour of traffic. The yellow suspension then light lit solid. Strange thing was that when the suspension dropped to L1, the UP button on the level control buttons was blinking as if I had had pushed it, which I hadn't. Also there are times when the suspension has read at L1 when it's actually at L2.
This morning I scanned the codes and again came up with 01577 - Turn-Off due to Over-Temp: Upper Limit Exceeded, and 01772 - Signal from Level Control Pressure Sensor (G291) 27-10 - Implausible Signal - Intermittent. I was able to clear the codes and raise the suspension back up to L2.
As I mentioned earlier, I replaced the front air bags a year ago with Arnott Gen I's and last week I replaced the compressor. I have fastidiously tested for leaks with soapy water and tightened connections everywhere I can get to. I once received the 01772 code indicating that the harness that feeds the level control pressure sensor has an intermittent short on it's 12V positive wire.
Hate just throwing parts at the problem without know exactly what it is. But with all these variations it's been hard to nail down exactly where the problem is. Thinking it could very well be the valve block/pressure sensor is shot as there seem to be so many variables. I haven't tried testing the tank for a Bar measurement, but with a new compressor in place there should be proper pressure.
Thanks for everyone's input on this problem.
08-23-2017, 02:43 AM
#18
AudiWorld Member
Suspension held for a week with no codes till 2 days ago. After driving a short distance the suspension error light lit up solid. I parked for 30 minutes and came back to see that the rear suspension had dropped to below L1 position, but the fronts were fine — the rears have never dropped separately, only the fronts or both front and back together.
I scanned the codes and came up with Upper Limit Exceeded, and 01772 - Signal from Level Control Pressure Sensor (G291) 27-10 - Implausible Signal - Intermittent. I was able to clear the codes and raise the suspension back up to L2. The car was fine for a day.
Then last night again after a 2 hour drive and then slowing down for stop and go traffic, I got the flashing yellow suspension dash light. The suspension dropped from L2 to L1 and then the held for another half hour of traffic. The yellow suspension then light lit solid. Strange thing was that when the suspension dropped to L1, the UP button on the level control buttons was blinking as if I had had pushed it, which I hadn't. Also there are times when the suspension has read at L1 when it's actually at L2.
This morning I scanned the codes and again came up with 01577 - Turn-Off due to Over-Temp: Upper Limit Exceeded, and 01772 - Signal from Level Control Pressure Sensor (G291) 27-10 - Implausible Signal - Intermittent. I was able to clear the codes and raise the suspension back up to L2.
As I mentioned earlier, I replaced the front air bags a year ago with Arnott Gen I's and last week I replaced the compressor. I have fastidiously tested for leaks with soapy water and tightened connections everywhere I can get to. I once received the 01772 code indicating that the harness that feeds the level control pressure sensor has an intermittent short on it's 12V positive wire.
Hate just throwing parts at the problem without know exactly what it is. But with all these variations it's been hard to nail down exactly where the problem is. Thinking it could very well be the valve block/pressure sensor is shot as there seem to be so many variables. I haven't tried testing the tank for a Bar measurement, but with a new compressor in place there should be proper pressure.
Thanks for everyone's input on this problem.
I scanned the codes and came up with Upper Limit Exceeded, and 01772 - Signal from Level Control Pressure Sensor (G291) 27-10 - Implausible Signal - Intermittent. I was able to clear the codes and raise the suspension back up to L2. The car was fine for a day.
Then last night again after a 2 hour drive and then slowing down for stop and go traffic, I got the flashing yellow suspension dash light. The suspension dropped from L2 to L1 and then the held for another half hour of traffic. The yellow suspension then light lit solid. Strange thing was that when the suspension dropped to L1, the UP button on the level control buttons was blinking as if I had had pushed it, which I hadn't. Also there are times when the suspension has read at L1 when it's actually at L2.
This morning I scanned the codes and again came up with 01577 - Turn-Off due to Over-Temp: Upper Limit Exceeded, and 01772 - Signal from Level Control Pressure Sensor (G291) 27-10 - Implausible Signal - Intermittent. I was able to clear the codes and raise the suspension back up to L2.
As I mentioned earlier, I replaced the front air bags a year ago with Arnott Gen I's and last week I replaced the compressor. I have fastidiously tested for leaks with soapy water and tightened connections everywhere I can get to. I once received the 01772 code indicating that the harness that feeds the level control pressure sensor has an intermittent short on it's 12V positive wire.
Hate just throwing parts at the problem without know exactly what it is. But with all these variations it's been hard to nail down exactly where the problem is. Thinking it could very well be the valve block/pressure sensor is shot as there seem to be so many variables. I haven't tried testing the tank for a Bar measurement, but with a new compressor in place there should be proper pressure.
Thanks for everyone's input on this problem.
08-24-2017, 08:33 AM
#19
AudiWorld Member
Suspension held for a week with no codes till 2 days ago. After driving a short distance the suspension error light lit up solid. I parked for 30 minutes and came back to see that the rear suspension had dropped to below L1 position, but the fronts were fine — the rears have never dropped separately, only the fronts or both front and back together.
I scanned the codes and came up with Upper Limit Exceeded, and 01772 - Signal from Level Control Pressure Sensor (G291) 27-10 - Implausible Signal - Intermittent. I was able to clear the codes and raise the suspension back up to L2. The car was fine for a day.
Then last night again after a 2 hour drive and then slowing down for stop and go traffic, I got the flashing yellow suspension dash light. The suspension dropped from L2 to L1 and then the held for another half hour of traffic. The yellow suspension then light lit solid. Strange thing was that when the suspension dropped to L1, the UP button on the level control buttons was blinking as if I had had pushed it, which I hadn't. Also there are times when the suspension has read at L1 when it's actually at L2.
This morning I scanned the codes and again came up with 01577 - Turn-Off due to Over-Temp: Upper Limit Exceeded, and 01772 - Signal from Level Control Pressure Sensor (G291) 27-10 - Implausible Signal - Intermittent. I was able to clear the codes and raise the suspension back up to L2.
As I mentioned earlier, I replaced the front air bags a year ago with Arnott Gen I's and last week I replaced the compressor. I have fastidiously tested for leaks with soapy water and tightened connections everywhere I can get to. I once received the 01772 code indicating that the harness that feeds the level control pressure sensor has an intermittent short on it's 12V positive wire.
Hate just throwing parts at the problem without know exactly what it is. But with all these variations it's been hard to nail down exactly where the problem is. Thinking it could very well be the valve block/pressure sensor is shot as there seem to be so many variables. I haven't tried testing the tank for a Bar measurement, but with a new compressor in place there should be proper pressure.
Thanks for everyone's input on this problem.
I scanned the codes and came up with Upper Limit Exceeded, and 01772 - Signal from Level Control Pressure Sensor (G291) 27-10 - Implausible Signal - Intermittent. I was able to clear the codes and raise the suspension back up to L2. The car was fine for a day.
Then last night again after a 2 hour drive and then slowing down for stop and go traffic, I got the flashing yellow suspension dash light. The suspension dropped from L2 to L1 and then the held for another half hour of traffic. The yellow suspension then light lit solid. Strange thing was that when the suspension dropped to L1, the UP button on the level control buttons was blinking as if I had had pushed it, which I hadn't. Also there are times when the suspension has read at L1 when it's actually at L2.
This morning I scanned the codes and again came up with 01577 - Turn-Off due to Over-Temp: Upper Limit Exceeded, and 01772 - Signal from Level Control Pressure Sensor (G291) 27-10 - Implausible Signal - Intermittent. I was able to clear the codes and raise the suspension back up to L2.
As I mentioned earlier, I replaced the front air bags a year ago with Arnott Gen I's and last week I replaced the compressor. I have fastidiously tested for leaks with soapy water and tightened connections everywhere I can get to. I once received the 01772 code indicating that the harness that feeds the level control pressure sensor has an intermittent short on it's 12V positive wire.
Hate just throwing parts at the problem without know exactly what it is. But with all these variations it's been hard to nail down exactly where the problem is. Thinking it could very well be the valve block/pressure sensor is shot as there seem to be so many variables. I haven't tried testing the tank for a Bar measurement, but with a new compressor in place there should be proper pressure.
Thanks for everyone's input on this problem.
10-06-2017, 08:25 AM
#20
Finally got to swapping out the front air springs. Unfortunately the fronts still drop overnight. So should I assume that there is an air leak between the valve block and the front springs? Do the air lines go bad? I swapped out the valve block as well just to rule that it's the problem. As I understand it the valve block's default is that all valves are closed.
I'm getting the usual dtc codes:
01400 - Suspension Level Control Sporadic: Resulting limit not reached
02538 - Function Restriction due to Overload sporadic
01772 - Signal from Level Control Pressure Sensor (G291) sporadic
01770 - Tempurature Sensor Overheating
I can tell my recently renovated compressor is starting to wear and struggling with all the action it's getting from working all the time. Can barely get to level 2 now.
As a side note, I replaced the front shocks (when I replaced the airsprings) with Arnott's SK- 2779 shock. Wow they are harsh! Any decent sharp bump and they slam the body. I'm going go back to my old oem shocks. They're worn but better than the Arnott's.
I'm getting the usual dtc codes:
01400 - Suspension Level Control Sporadic: Resulting limit not reached
02538 - Function Restriction due to Overload sporadic
01772 - Signal from Level Control Pressure Sensor (G291) sporadic
01770 - Tempurature Sensor Overheating
I can tell my recently renovated compressor is starting to wear and struggling with all the action it's getting from working all the time. Can barely get to level 2 now.
As a side note, I replaced the front shocks (when I replaced the airsprings) with Arnott's SK- 2779 shock. Wow they are harsh! Any decent sharp bump and they slam the body. I'm going go back to my old oem shocks. They're worn but better than the Arnott's.