Need help suing the BMWNA for CPOed X5

[JonK]

I CPOed and bought 2005 X5 at the end of lease 6 weeks ago. After 3 weeks of the purchase. The X5 developed a plethora of electrical problems that I have mentioned in this thread.
http://www.xoutpost.com/x5-e53-forum/...hlight=massive

8 days after I took the car to the dealer, they claimed they have somehow fixed the car by plugging out all the electrical plugs and putting them back in. While I was communicating with the adviser he told me they have not identified the problem such as an error code, etc.. As a conclusion they suspect bad electrical contacts and claimed they have resolved the problem.
A day after I took the car back, the problems started again. I start seeing every warning messages conceivable such as 4X4 failure, Trans Safety Prog, etc. My wipers completely stopped working during the heavily raining day. Wiper fluid started squirting without being initiated. The seat belt, brake, and airbag warning light remained on with no reason.

I took the car back to the dealer last Friday to the reluctant dealer who hasn't returned my repeated calls. The service adviser said he will try to have a BMW Engineer come resolved the problem. Just an hour ago I got a call from the same guy who promised to fixed the car saying that BMW denied the CPO coverage and now I have to pay the hourly rate for their attempts to repair the car.
I am going through the California Lemon Law via internet but so far I haven't found anything that is encouraging. Is it common that BMW deny repair claims only because they don't know how to fix it?

Of course I am mad as hell and looking for the ways to make it right.
Why would anyone buy a CPOed vehicle if dealer gave up fixing the vehicle because they do not know how?
I would really appreciate any inputs.
Thanks in advance.