2003 gmc envoy code p0128

ect sensor wwear is it full of antifreeze what does it mean 2003 gmc envoy 6 cylinder 85000 miles
LF of block, near alternator. Why are you looking for it? Trouble code?
Loren
SW Washington po128code maybe sensor
That's not necessarily a bad sensor. The code means the sensor is reading lower than the engine should be running. That could just as easily be a bad thermostat causing the engine to actually run too cool. You really need a scan tool to see just when temp the PCM is seeing and whether that is the actual temp of the engine. It can also be related wiring causing the problem.