I recently acquired a 94 850 non-turbo, my first Volvo. While driving home today the check engine light came on. Checking the codes when I got home revealed a 1-2-1 (Manifold Absolute Pressure (MAP) signal absent or faulty) code and a 2-3-2 (oxygen sensor control/long term fuel mixture too weak at idle) code.
First off, after researching am I correct in my conclusion that the 94 850 does not have a MAP sensor but a MAF sensor? Most of the issues with these codes I have found instances of online seem to come down to a bad MAF sensor and that was my initial suspicion. My car was running fine down the road but began idling rough while doing diagnostics (bouncing around in the 600-800rpm range). Clearing the fault codes erased the 2-3-2 code but the 1-2-1 remained. Following some suggestions I found on the forum I tried to isolate the issue in the MAF sensor if it was there. Unplugging it's electrical connection while the car was running resulted in it stalling out immediately. From what I found, the car should have still run with it unplugged. Another suggestion I found was that the coolant temperature sensor fails and more errors precipitate from that. Any ideas what is going on here? Thanks.

 

The first thing you should do is read the "New 850 Owner" thread.

My suggestion is for you to check your vacuum lines and elbows.

 

'94 850 no turbo, will not idle; on occasion after warm up.

 

My advice to you would be...







..start a new thread!