OVP's effect on the engine depends on the type of fuel injection system fitted. However the give away is that if it fails it will always bring up the ABS light. certainly has nothing to do with climate control or A/C.
gmaltz, how is the engine temperature - on some models the a/c shuts down if engine gets too hot (over 120 degrees)
'08 Chrysler 300CRD (MB OM 642 engine)
'95 E220 estate
'89 230TE (R.I.P.)