Volvo Repair: map sensor connection, turbo wagon, auto air

Question
Hi, I have a 94 850 r turbo wagon with auto air and has 101,000 Miles the MAP sensor connection has 4 wires and there is only 12 volts to one no other power to the other 3 wires.

Any idea on how to check the connector to make sure it is correct?

Thanks

Bryan

(car is running very poorly wont idle and will stall)

Answer
One wire is power
One wire is ground
One wire is signal ground
One wire is signal

12v at the first, ground at the second, intermittent ground at the third, and vary voltage with vacuum change at the last one.  I don't know which wire is which though until i look at a diagram and We lost the diagrams for that year 850 at the dealer.  That should give you some kind of idea though.

James