By the time something is detected I would assume it's because there's already a failure. I'm guessing the valve will likely work until the module overloads and burns out. I guess there may be a point of low resistance where the module can't properly control the valve but hasn't overloaded to the point of burning out, but I think it would be hard or impossible to detect, especially if the load is rising slowly over days or weeks, maybe even months.

 

There are several failure modes. So it depends. Sometimes the DCCV does keep working but draws too much current. Other times it fails to operate anymore. We did not find out about the module getting damaged until a good number of DCCV's had been changed out.

Then reoccurring problems showed up and the new DCCV's checked OK. So that finally pointed to the CCM/RCCM being damaged by the bad DCCV.

Eventually someone looked deeper and found the module was poorly designed and had no protection on the output drivers. Maybe Jaguar just never thought of a failure mode where the DCCV draws a large amount of current, so they did not spend the money on circuit protection?
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I think they also expected the Bosch DCCV would be far more reliable than turns out to be the case.

 

Considering they also buried it where it's a pain to get to, I hope that was their thought. Then again, they used that same DCCV for several years (I think) without ever adding protection so maybe they just don't care since they're probably not having many failures within warranty. Anyone know when they started and stopped using that DCCV and if protection was ever added?

 

Latest date they stopped was 2007 when they made the last S-Type. The 3-port that fails so often came in 2003 USA (2002.5MY).