2008 GMC Canyon with engine code P0128

Question

my 2008 G.M.C. Canyon is giving me the p0128 code / also the check engine light keeps coming on and it is also saying A.C. off/ and at this point the temp. gauge drops to the bottom when the truck is running after a while it will pop back up but never getting past the half mark the truck is not getting hot at all all levels are fine no leaking i have already replaced the engine col-lent sensor its still doing the same thing ok my question is before i replace the thermostat is last yr i replaced th e Engine control module and this code has been coming on since could that be thew problem or should i go ahead and replace the thermostat

Answer 1

This code condition was occurring after the ECM was replaced? Then this may just be related to the ECM being replaced. You can use a scan tool if there is a datastream you would be able to measure the temperature that the ECM see.

Answer 2

P0128 GMC - Engine Coolant Temperature Below Thermostat Regulating Temperature
Read more: https://www.autocodes.com/p0128_gmc.html