My son reported his '95 850 has an intermittent but frequent stall - (see previous note). Car apparently runs fine when not stalled. Following up on already good advice from the board I got more details from him:

Read diagnostic codes:
A1 114 - Program Selector Open Circuit (sport/econ/winter mode switch)
A1 223 - Throttle Position (TPS) Sensor Signal Too Low

He cleared the codes and drove it today. Says at a stoplight the idle fell to 700-800 rpms, then returned to normal. Just before getting back to the dorm the radio (aftermarket, not Volvo radio) turned off, then 5 seconds later the car died. Turned key - nothing: no lights, no click, nothing. Even the emergency flashers didn't work. Got out and jiggled the battery cable and the horn honked! Got back in and car started. He does not remember if the check engine light had come back on.

Suggestions so far:
- ignition switch
- throttle position sensor (diganostic code A1-223)
- sport/econ/winter switch (diagnostic code A1-114)
- bad grounds (any in particular?)
- loose wire (where?)
- wiring to main system relay
- fuel pump (or fuel injector) relay
- friend of his says he had the same problem in a v70 that was caused by subwoofers pulling too much current (there are subs in the car)
- probably a few others

There are lots of clues but I haven't been able to put them together. It is possible the program selector switch and throttle position sensor went bad at the same time it seems unlikely. Would that cover these symptoms? Where to start? Any suggestions for how to narrow it down or rule something out?

Thanks,

Terry


History: 2 weeks ago went to car and it was dead (nothing happened when turned key). Bought a new battery which mechanically disinclined son installed. Problems continue.