I recently rescued a 1992 Olds 98 that had been sitting unused and unloved for about 3 years in a garage with only 40K miles on it. After a brief trip to the repair shop, it is running well, averaging 23 mpg highway, with cold air conditioning. There is one puzzle, however. Here it is: The “Service Engine Soon” light comes on as soon as the engine warms up. The repair shop tells me the diagnostic code is 41, which means “cam shaft position”. The shop further tells me that if the warning was accurate, then the car would not be driveable, but that is obviously not the case because the car performs very well. The shop advises me to ignore the warning and treat it as a computer glitch. Should I follow the shop’s advice?
The thing to do would be to have the repair shop run down the diagnostic chart for the code. That would tell you if there is something that has failed and needs to be repaired. If they can’t perform the diagnostics then you need to find a shop that can.
The Cam Shaft Position sensor sends a signal to the computer so it can set the ignition timing and the fuel injector timing. If the sensor signal is lost, the computer will go into default mode so the engine is still able to run. This usually results in a richer fuel mixture and the retarding of the ignition timing. So if this problem is resolved to where the Check Engine light no longer comes on, you’ll probably see an increase in fuel mileage along with improved performance from the engine.