Temperature sensor 04 Trailblazer/Envoy 6cyl code says it may need to be replaced

 

Codes never tell you what needs to be replaced they only tell you which system is being afffected. Does the code happen to be po128?

 

I actually took it to my local Autozone and let them scan it guy gave me a printout with 3 potential items that could need attention. Low coolant temp sensor or thermostat I checked and added coolant but check engine is still on so I am doing a process of elimination. If I can remember what I did with the printout I will see if there were any codes given and what they are and post them.

Thanks for your help Anthony.

Ecomonic cicumstances have dictated i have to do some of my own stuff again which I haven't in many years but you know I had forgotten how satisfying to get out there and do it myself although frustrating as all get out at times.

 

chances are it is P0128--
and if you have some miles or yrs on your Trailblazer..
its most likely the thermostat....


You can test this....
on a cool night-- look at the temp gauge- get on the highway- and open your windows..
get to about 55 MPH and stay there-
then turn on your HEATER to full.

The low RPM's, the highway speeds, and the heater also dissipating the heat- will lower the coolant temp enough--- that if the thermostat is lazy--- it will be slow to close or not close at all--
pretty soon you may see the needle DROP...

if you get off the highway- turn off the heater and your needle goes back up...
time to change the thermostat.

 

Replace the t-stat. It will fix it 99.9% of the time. The light will take a while to go out on it own. It could be turned off with a scan tool.

 

Cant you just leave the negative battery cable off over night to clear the code also?

 

only need to disconnect the battery for 2-10 min to allow any capacitive charge to dissipate, the code will clear as soon as power is lost to the ECM.

NOTE: it is best to use a code reader to clear the code rather then disconnect the battery most obvious reason is setting your clock, but the ECM does have to go through a brief relearn period, not a big deal but your vehicle may drive differently for a bit and is best to be driven for several miles... or so I have been told.

 

Code P0128. As you mentioned, process of ellimination. But back to original question, where is the ECT sensor on 2004 Trailblazer?
Arty.
Found it. It is underneath the air intake tube. It's the only plug you see out of engine.