OK, get ready for an interesting story...just got an email from a fellow at IATN who had the same problem with a 960 caused by the wrong torque converter being installed during an engine swap...the interrupter ring on the '92 and '93 models are different - they're basically inverse copies of each other - one is mostly a continuous band with gaps, the other is a mostly contiuous gap with a few "teeth" for cylinder identification ...you'll still get a proper looking scope trace of the crank sensor signal, but it's actually ass backwards. this IATN guy's problem child came in for a crank sensor code. he replaced the sensor and it wouldn't start. then he found out about the engine swap and finally realized the problem and got the right converter installed.

my customer's was in for the first time 6 months ago for an engine swap. he supplied the engine, which he got from a Volvo collector guy in town. i couldn't get the transmission to line up due to a mismatch at the crankshaft/torque converter, so the customer went back to his guy and got the converter from the donor vehicle...his guy swore that all parts on '92 to '95 960s were interchangeable - i told him that if anything went wrong, it would be his problem...

what's really strange is that in both of these cases, the engine started and ran for some time with the wrong converter installed...how/why the ECM finally decided that that there was a problem is beyond me!
JUST GLAD TO HAVE IT SOLVED!!
hope this info will be useful to others.