So this is my problem ? That piston ring ?

1. If i order it, is hard to change it ?

2. If i disconnect the compresor to change the ring, the car will be low ?

3. After i change the ring, just plug back the compresor, delete the error with Inpa, and the leverl button will work to rise and low the car ?

Sorry for all my questions, but i'm a bit affrair, not to do something wrong and can't use the car anymore.