M - I had a similar problem to yours with my 2008 CTT with PDCC. When I started it, it said chassis system fault. When I tried to put it into sport mode - it again said Chassis Fault. It was an expensive fix - labor and parts. There were several hydraulic lines that were worn - so those had to be replaced. And similar to this video posted for a later car, the pressure sensor also needed to be replaced (under the rear seat). While they were at it - they replaced the PDCC mineral oil reservoir (common item should be replaced periodically to keep things clean). The system was bleed and tested. Been working great every since. I don't think the repair is a DIY job unless you really understand everything. Most of the pieces were a remove and replace. But the testing of the system - running it through the various settings - I was not sure how to do this. So I paid the price. But PDCC is the best feature when working.