I have had this P0128 Code for over a year now - so it obviously is not causing problems because the engine runs fine, great gas mileage, etc. The problem says that the thermostat should be replaced; but that is very involved and expensive. Are there any other things I can try? It seems strange the the Check Engine light would stay on (even after reset) for the same thing yet not cause any obvious problems. I know TBs have instrument cluster electric problems.
2004 TB P0128 OBD Code on 2004 Chevrolet Trailblazer
by jsgoofn in Broomfield, CO on January 18, 2011
1 answer 1 comment
ANSWER by mastertech6371 , January 18, 2011
it does not say the thermostat needs to be changed. what the code identifies is that the engine is not running at the temperature it is supposed to run at. the coolant sensor may be at fault or wiring or maybe the t stat. that is what a diag will tell you. get it checked by a shop instead of throwing parts at it. Roy
COMMENT by Visitor , January 18, 2011
Hello, Roy - I made a mistake by saying that is what the code meant. I should have said that when I researched the possible reasons for the code, one of them was to replace the thermostat. I will get it checked by a shop as you suggested.