OBD2 is purely for emissions related faults, to talk to the rest of the systems you need a specialised scan tool. Some car makers were nice and kept the same protocols for all systems meaning a generic scan tool works. Chrysler were not nice and there is a very limited number of professional tools that can talk to all systems. If you are down cambridge way I can clear it for you and (hopefully) diagnose the fault...but it's a long trip for you.

Regards
Richard

Richard, that's a fine offer and I appreciate it. If I can find an excuse to come down Cambridge way, I shall use it! Thank you. Dave.