Audi A6 4F air suspension not raising

Hello everyone,

My Audi A6 4F, manufactured in 2005, was in the garage for 3 years due to a period of living abroad. Before that, everything on the car was in good condition. During this time, the air suspension system lowered. The car starts and runs normally, but the suspension remains in the lowered position. I can access control unit 34 using VCDS. However, it is not possible to bleed the pressure reservoir or the front or rear air springs, nor is it possible to initiate the default height setting. When I try to adjust the suspension using function 31564, selecting "initial spring leg front left," I receive the message "Channel not available" after a short time. The compressor does not activate. The fuses, relays, and height sensors have been checked and were okay, but they were replaced as a precaution, along with the compressor and the valve block. All components are working correctly. When I connect the compressor directly to 12 volts, it runs. The suspension raises after some time and maintains the air pressure for days. Therefore, the air bladders are airtight. Does anyone have any ideas where the problem might lie, or whether I need to change anything in the programming sequence using VCDS?

I'm at a loss now... Thank you in advance for your help!

Hello,

The air suspension can be lowered, and I have some reports to that effect. However, the alignment seems to be tricky, and nothing was broken on these cars.

Perhaps the instructions and the things to keep in mind will be helpful to you.

Okay, I'm ready. Please provide the German text you want me to translate.

Best regards, Rainer.

Hello Rainer,
Thank you for the quick response and the tip about the manual. I have already adjusted various Audi air suspension systems using VCDS, which generally works very well. However, in this case, I'm at a loss. Perhaps someone knows the best way to proceed when a vehicle fails to raise after such a long period of inactivity. Could it be necessary to completely re-initialize the control unit...? If so, how and in what order?
Thank you in advance for your help!

After 18 years of riding Allroad bikes, I've definitely experienced quite a bit.
Check the temperature sensor in the extended measurement blocks. For that, you need to enter the login code.
The temperature value displayed in the main blocks is the calculated value. In the extended measurement blocks, the actual temperature value is shown. If the sensor's resistance is too high, resulting in a displayed temperature that is too high, the compressor will not turn on.

Great tip. Thank you very much. It will be tested tomorrow!