Pontiac Repair: High temp reading onn gauge, gm dealer, insterment

Question
Pontiac sunfire 2004 temp gauge max out pass red danger and the engine actual temp was normal. WHAT COULD BE THE PROBLEM, the gauge or the sending unit. or could there be another cause

Answer
Hi Jonas:

It's more than likely the temp gauge it's self. That car uses the same sensor for the engine control module and the dash gauge. If the sensor was bad and telling the gauge it's that hot the car would start really hard whenit's cold and since you didn't mention that I would assume the sensor is good. You have to get a complete insterment cluster assembly to get that gauge and it's a dealer only item they have to get them from a regional rebuild facility. Getting one from a junk yard is not feasble because there are a few different options available they may physically look the same but the internal components are different. To be completely certain that's what it is I would stop at your local gm dealer and just apy them a minimal diag. fee to scan the engine control computer to make sure the temp sensor is good and they can also perform a gauge sweep test with their scan tool on the IPC. Good luck :)