General Information

P0128 Coolant Thermostat (Coolant Temperature Below Thermostat Regulating Temperature)

General Information

Component Location





General Description

The Thermostat is a mechanical (thermal) device located in an engine coolant passage that allows passage of coolant into the radiator once the coolant has reached a manufacturer specified temperature called the Regulating Temperature. It has a metallic frame with a spring-loaded,centrally mounted, wax filled cylinder/piston assembly that expands and contracts with changes in temperature, thereby controlling the passage of coolant into the radiator.

DTC Description

If the engine coolant temperature does not reach the specified value within the allocated period, the PCM sets DTC P0128.

DTC Detecting Condition





Schematic Diagram