1997 850. Purchased this vehicle about 4 months ago. Temperatures have begun to rise in Kansas this past week, days averaging 90+. Noticed last Saturday morning (about 90 degrees at the time) the Service Engine light come on for about 1/2 mile of driving then goes out. Checked hoses, listened for airleaks, etc., and other obvious things but didn't see or hear anything notable. Didn't come on any more on Saturday. Sunday, same thing, light came on duruig morning idle, went out after I drove about 1/2 mile again. Now whenever I turn the car off and recrank, it reoccurs and still goes out after 1/2 mile of driving. Thought it might be oxygen sensor (do not have maintenance records, so it's hard to tell when it was last -- if ever -- changed). Any ideas on where to begin diagnosing would be greatly appreciated.

That is just a message that the car needs an oil change, it goes off after 2 minutes. My 1998 needs a special tool to turn it off, so it has been doing that for the last 6 years! Total ignore on my part because I never go to the dealer for an oil change.

There is a way to turn off your light, but I forgot. Perhaps a search for 'service light 850' will get you an answer.

If you happen to take out the instrument cluster to replace bulbs, just remove that bulb. Or a piece of black tape?

Klaus
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Always willing to listen, just not able to take direction.

Thanks Klaus. I changed the oil and filter 26 days ago. And I'd changed the oil during the week I purchased the vehicle (February 2011). Could infrequent oil changes by the previous owner be producing this? I can easy-enough ignore the light, just don't want something to be looming that I could take care of now with some investigation. When I finally get the gear and the time to fix the classic broken odometer I'll consider removing the bulb for that warning light as well. Any other ideas on this issue?

The service light is a 'dumb' system, ie. it is miles driven and nothing else. The system can accept either 5,7.5, or 10K miles, some such nonsense. It takes a dealer tool to turn it off.

If your odo is broken, the dealer can get the mileage from the computer so long as the instrument cluster is still in the dash. Then you can use a pencil with eraser in a drill to drive the odo up to the proper mileage. Lifting the left side of the dash to get the cluster out is not hard.

Klaus
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Always willing to listen, just not able to take direction.