Primastar Air Suspension Problem

Leaning and ride height issues, along with the error message, do suggest a problem with the air suspension system. Is the compressor running constantly, trying to compensate? Have you inspected the air springs for any visible signs of damage or heard any hissing sounds that might indicate an air leak?

I have not specifically checked if the compressor is running constantly. I did not hear any hissing sound but I will check for it again. What does the bellows valve do, exactly, and how would a defect there manifest?

The bellows valve, also known as the air spring valve, controls the inflation and deflation of the air springs. A defective valve can cause air leaks, preventing the system from maintaining proper ride height, thus leading to the symptoms you described. I would suggest a thorough inspection by a qualified mechanic to confirm the valve's condition, and potentially the air compressor as well. It is likely the bellows valve is defective.

Thank you for the clarification. I followed your advice and took the vehicle to a workshop. They confirmed that the suspension air bag valve was indeed defective. The repair, including parts and labor, cost 590€. The system is now functioning correctly.