Thromostat / temp sensor

does anyone know where the "coolant temperature sensor" is on an 02 Trailblazer? Code P0128 is in my OBD-II, and it means the temperature sensor is measuring coolant temperature below what the thermostat is regulating. Looks like i need a new temp sensor... I bought a new thermostat just in case that does not fix it, but the thermo is burried behind the power steering pump (BTW... THANKS GM!)

Where is the coolant sensor?

Thanks!

does anyone know where the "coolant temperature sensor" is on an 02 Trailblazer? Code P0128 is in my OBD-II, and it means the temperature sensor is measuring coolant temperature below what the thermostat is regulating. Looks like i need a new temp sensor... I bought a new thermostat just in case that does not fix it, but the thermo is burried behind the power steering pump (BTW... THANKS GM!)

Where is the coolant sensor?

Thanks!

Sorry, have no answers for you as I may have a similar problem. Was wondering why my 02 TB was not really heating up. This AM, it only got up to about 160 degrees while driving on I95 and the Check Engine Light eventually cam on. Noticed the heater was not blowing really hot for the past few days. Haven't had a chance to look into it yet - don't know if it is the thermostat or some sensor?

My Trailblazer is only heating up to about 130. I've read that it might be the Coolant Temperature Sensor, but I'm not sure where that is. I tried taking the Thermostat off to replace it, but ran into 2 problems. Advanced Auto Parts gave me the wrong part and I have no idea how to get the thermostat off. Please Help.

My Trailblazer is only heating up to about 130. I've read that it might be the Coolant Temperature Sensor, but I'm not sure where that is. I tried taking the Thermostat off to replace it, but ran into 2 problems. Advanced Auto Parts gave me the wrong part and I have no idea how to get the thermostat off. Please Help.

The top bolt for the thermo housing is easy, but the bottom one is behind the power steering pump. you have to remove the serp belt, the PS pump, and then you can get to it. Its not too fun. good luck.

Before replacing the sensor, you need to check the basics.
Is the cooling system full?
Most likely one of two senerios have taken place.
The thermostat is stuck open not allowing the engine to reach operating temperature or its extremely cold and the engine is not warming up as fast as the PCM wants.

Did you fix yours, How long did it take? Was it the sensor or the Thermostat? My Service Engine Light is also on.

Did you fix yours, How long did it take? Was it the sensor or the Thermostat? My Service Engine Light is also on.


mine is fixed, dont know which one it was because both the thermo and temp sensor were replaced. had a local shop do it, (didnt want to rip out the PS pump). your SES light is probably on due to code P0128. goto Autozone, they will check it for FREE.

Hopefully i am done with electrical issues! probably not though...

If you don't mind me asking, What was the cost? Did you have them buy the parts or did you supply them?

i supplied the parts ($25-thermo $17-sensor) and the laber was 1.4 hours... $154 for all.

I have one more question. I went to advanced auto parts to buy the thermostat, they sold me one that didn't fit. I took it back and they had nothing to fit it. They told me it wasn't an aftermarket part and that I would have to go to the dealer to buy it. Is this true, did you buy yours from the dealer?

NAPA - $30 or so... Make sure you get the one with the seal. here's a link:

http://www.napaonline.com/masterpages/NOLMaster.aspx?PageId=470&LineCode=THM&PartNumber=426190&Description=Thermostat+-+OE+Specified+Temperature+190+Degree

It looks like the same one I got from Advanced Auto Parts. It doesn't look like it will fit. My thermostat makes a 90 degree turn towards the front, this doesn't.