P0128 Code..07' Pontiac G6...55K miles?

CallawayGolfer

New member
P0128 - Coolant Thermostat (Coolant Temp Below Thermostat Temp)

Autozone said its most likley my sensor and should be about $30 for the part. My question is, is that what it sounds like and can I do it myself?

**Also, my temp gague on my instrument panel is not working** Autozone said its because my sensor is bad...
Its suppose to be right in the middle of hot and cold but its just burried at the bottom of cold and will not move.
 
It seems it could go either way with this particular sensor. This sensor is not the coolant temp sensor but the thermostat temp sensor. This indicates that the temp. for the thermostat is below what it should be and that the thermostat should have opened after a certain amount of time after starting. But of course I would first check the sensor and see if Auto Zone can give you a print out of the location and how to do it. Its hard to test this sensor because the thermostat has to open for you to get the correct reading. Its best to remove and put sensor into some boiling water and try to get the readings of the sensor while still hot. If the sensor is within spec then you can replace the thermostat.

But if your problem still persists you might have a problem with your PCM. It might not be reading correctly and causing problems. This is caused by software problems with the PCM and just like your PC the cars computer needs updates every now and then. The only draw back is that the Dealer is the only one that can resolve update issues. Very few Independent shops will be able to resolve this problem

So try to check the sensor and the thermostat first. If you can't resolve it take to the dealer for an in depth analysis of the concern. Here's the definition of your code on the obd II website http://www.obd-codes.com/p0128 . Good luck.
 
Yes, it could be the sensor. Could also be the wire harness. The sensor itself is easy enough to change. Unscrew it and screw in the new one. Do it with engine cold so you don't get burned.
 
Yes, it could be the sensor. Could also be the wire harness. The sensor itself is easy enough to change. Unscrew it and screw in the new one. Do it with engine cold so you don't get burned.
 
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