I have an 05 and have hard a few air suspension woes. Of course the dealer tried to get out of paying for them but ended up admitting the CPO warranty covered the front right strut. They replaced the strut and still had issues. They had the car for 3 weeks and finally found the problem, one of the fittings had a pin hole leak. They R&R free of charge.

I had the left front strut replaced under the original warranty at 40k, and the right front was replaced at 63k and the leaking fitting shortly thereafter. I am currently at 84k and all is well. If I experience another suspension problem, I will most likley throw a set of KW's in her.