BIG-DAVE

ok i havw a 2.2 and i keep throwin this code p00128 does any1 know what that is it would help alot thanks .....

redlineblueline

its your thermostat

Halfcent

Please try a search. We have a sticky right in the general section with the DTC list.
https://www.cobaltss.net/forums/problems-service-maintenance-69/cobalt-dtc-thread-merged-12015/

P0128 Engine Coolant Temperature (ECT) Below Thermostat Regulating Temperature ECM, PCM

Probably have a stuck open thermostat.

At this point, the tech goes to books to determine the troubleshoot. You are probably still under warranty, just take it to the dealer are get it fixed for free.

3fo893013L

Are you overheating? most likely scenario is your thermostat is stuck wide open and cannot close or the direct opposite.