We bought a 1994 Volvo 940 Turbo Wagon when it was new. My wife has driven it for 16 years without a problem. Now, without warning, the engine stops, all dashboard lights come on, and she has to pull off the road. The car has, up to this point, re-started without problem and she can continue on her way. This has happened about 6 times over the past 4 months. She wants to sell the car because she can't stand the uncertainty of when or where it will die again and whether it will start or not. Our mechanic has no idea what's wrong. He said to tow it in next time it happens and maybe he can figure out the problem. It has always started up right away after dying so I don't want to have my wife call a wrecker just to find out the mechanic still doesn't know what the problem is. Has anyone ever experienced this type of problem?

 

My wife had a similar problem with her 240 wagon. Always an intermittant failure. Took a year before it hard-failed and I was able to diagnose it as a failed fuel pump relay.

That is the first thing I would check given the symptoms you describe and the age of the car. You can pick up a new relay or, if your handy with a soldering iron, just re-solder the joints of the relay. The relay is usually the gray plastic one underneath the glove compartment. You should hear it click when you turn the key on.

Check the fuse as well (I don't know which fuse it is on a 940).

 

Oh yeah my car started doing this a while ago. First thing I checked after making sure I had a spark was the fuel injector relay, when I tried to pull it off all its insides came out in a puff of dust. Must have been original, surprised it lasted however many decades it lasted. Found a new one at the Volvo Recycler, was all better in a matter of hours. So yeah, check that fuel injector relay and that fuel pump relay. I've never actually had to test a relay myself, I'm not sure how to do that. All the bad relays on my car have been either obviously disintegrating or obviously melted.

 

My identical model has same problem last summer. The fuel relay was good but the problem was a failed power stage module. It is about 2 x 3 inch black bracket with a silver plate on it. Located on the right side above the wheel well.

 

Intermittent problems are hard to diagnose. Unless you're lucky replacing things piece by piece, the best thing to do is wait for the car to die completely. Then the symptoms are constant and it's easier to diagnose. Go to www.stepbystepvolvo.com for free guide to 740 no-starts. Has some info for 940s. The rpm sensor could be the culprit.