Code PO128

[ratrod67]

Can anyone tell me what to replace to make this code stop? 2001 Silverado 4.8

PO128: Coolant temp below Thermostat regulating temp

[edhtrd71]

Replace the thermostat. This dtc sets if a predetermined amount of time has gone by and the coolant temp is lower than the thermostats rating. The tstat is sticking open or opening to early. Very common on newer cars.

[ratrod67]

Originally Posted by edhtrd71

Replace the thermostat. This dtc sets if a predetermined amount of time has gone by and the coolant temp is lower than the thermostats rating. The tstat is sticking open or opening to early. Very common on newer cars.

Thanks for your reply. Is there anything else it can be? I replaced the thermostat 2 weekends ago and the code still comes back. Maybe a new thermostat that's bad??

[truckdude239]

Bad temp sensor if the t-stat been changed