Pontiac Problems? Ask a Mechanic for Answers ASAP
Hi my name is ***** ***** I will be happy to assist with this today.In some cases I may need more info to assist better.I apologize for any delay.
On this model the PCM (engine and transmission computer) send the signal to the dash gauge to control the temp gauge itself.There are electronics in the instrument cluster that control the actual gauge and one of them is stepper motor.This stepper motor is common to act up intermittently in the gauge assembly itself causing this fault here needing replaced as I have seen and had to do several times in the past.
The PCM wont click but the stepper motor can in the instrument cluster.So this does sound like the fault is with the instrument gauge cluster itself needing removed and repaired or removed and replaced.
If you can I would have the fault codes checked using a scan tool that will plug in and communicate with the instrument cluster to see what codes are set as well as the scan tool used to do a gauge sweep test to help verify the instrument cluster needs repaired or replaced.
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Did they check for codes in the instrument cluster at all?In allot of cases they will only check for codes in the engine/transmission computer and this can be why no codes were detected here.
I do suspect this fault is in the instrument cluster with the stepper motor for the gauge acting up as this is common.But this will have to be checked into/tested further to be sure which will involve a scan tool that can communicate with the instrument cluster to observe the coolant temp data to see if it reads correctly when the fault occurs.If it reads the correct temp when the gauge is acting up then the instrument cluster needs replaced.
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