My 1988 Bonneville pulls a check engine light when the car starts to warm up to its normal operating temperature, about the middle of the temp gauge (190-220 F). When you accelerate and get up to speed and the car cools down it will flash on and off depending on how much the car has been idling. I used a code reader and it flashed 14 and my book said it was a coolant sensor or high temperature. The car has a brand new radiator and fresh coolant/water and it never goes above the 1/2 mark on the temp gauge even in 100F weather. So should the sensor be replaced or can it just be jiggled around or something to stop showing the service engine light. If I replace it how do I go about it. My shop manual doesn't give a good picture of where it is located and I can't stand seeing the check engine light keep flashing on and off while driving.

3.8L Vin C 3800 Pre Series
110,900 Miles

Is this the only code being thrown?

Assuming the gauge is correct, and it's not actually overheating, it could also be caused by a short, which could be either wiring, or a bad sensor.

If memory serves, there should be 2 senders, 1 for the ECM, one for the gauge. They are down the drivers side of the engine block, and can be very tricky to spot with the throttle body, and exhaust crossover in the way. I also believe they are the only sensors on the driver side face of the engine block as well.

I also had this code set on my with several others when I thought the ECM was packing up, only to find that the battery was bad, and may have been causing the ECM to trip out.

Given potential age of the sensor, ruling out any obvious wiring concerns, I don't see the harm in replacing the sender, assuming you can get to it. The easiest access I had with mine (on my L27) was when I was doing the UIM/LIM job and had the manifolds off. It was staring me right in the face, but I didn't replace it as there was no reason to then.

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~Randall~


1993 Buick Park Avenue - 197k - Some odds and ends done - Simply won't die
1994 Buick Regal - 78k - Bone stock - Always ready for a good kicking
1990 Oldsmobile 88 - Gone to a better place