Automobile(s): 08 STS4 V8 F55 1SG Euro tails & 01 Monte SS Pace Car
Re: 2005 XLR Cruise Control Issue
I wont pretend to know much about the DSCC used in the XLR, but I would have to assume that the adaptive cruise control system used in the XLR is likely designed similarly to the STS that I have.
My STS has had a lot of radar cruise control issues, each time the 'faulty part' had been the multifunction lever.
Before I bought the car it didn't work, the dealer told me it needed a new radar cruise module ($1k+ part), I made it part of the sales deal that they repair the cruise.
They agreed to fix it before delivery. fast forward a few months and about 13,000 miles worth of driving and more cruise control issues started happening, dealers had issues figuring out what the issue was and what was causing it.
Eventually I called the selling dealer to ask them what they actually replaced. Found out it was the Multifunction lever (less than $100 part) that they actually replaced. Told my dealer to look into that part and it was reporting open circuit from time to time but it wasn't storing codes for it long enough for me to have issues and them to see the code.
So basically what I am saying is get to know that cruise system very well before trying to locate and spend that kind of money on a part when it could be a different part.
You may also want to check the connections/cleanliness of the connectors etc...
Also Chris Heath at Rippy Cadillac is a good place to get parts for a good cost and he will go above and beyond to get things done if its at all possible.
(got my export STS lamps from him that other dealers wouldn't consider ordering for me, was able to locate navigation firmware upgrades for the STS that other dealers said didn't exist)