OBDII Trouble codes

I have a 2000 Grand Prix and the check engine light comes on. The scan tool reads the code 0128 coolant temperature not up to proper temp. I'm confused on what it's telling me to fix? Does the thermostat need to be changed? Or is there some other problem? If I clear out the code the "service engine soon" light comes on a couple weeks later. If anyone knows any info I'd sure appreciate your input.

I have a 2000 Grand Prix and the check engine light comes on. The scan tool reads the code 0128 coolant temperature not up to proper temp. I'm confused on what it's telling me to fix? Does the thermostat need to be changed? Or is there some other problem? If I clear out the code the "service engine soon" light comes on a couple weeks later. If anyone knows any info I'd sure appreciate your input.

It would be helpful to know the mileage, model and engine you have in your GP. It means the PCM has detected an improper warm up condition. Normally the thermostat is sticking open. Also the ECT - engine coolant temperature sensor could be out of calibration but I doubt that.

I used to get that DTC error code when I ran a 160 degree thermostat in the winter before I installed a DHP PCM.

In generic terms the coolant temperature is below thermostat regulating temperature.

Sorry, 2000 Pontiac Grand Prix GT sedan 3.8 L V-6 with approx 73,000 miles. If the Thermostat is sticking is it easy to get to? Or if its the sensor where the hell is it located? THX

Sorry, 2000 Pontiac Grand Prix GT sedan 3.8 L V-6 with approx 73,000 miles. If the Thermostat is sticking is it easy to get to? Or if its the sensor where the hell is it located? THX

Easy job. Just follow the procedure in link below:

http://www.pfyc.com/supportfiles/tstat/tstat.htm

The ECT sensor is located right below the thermostat assembly about 3" -4 ".

Good luck!