Detection Condition
DTC P0126: If ECT signal never exceeds 160°F (71°C) after engine runs for a certain period, PCM determines coolant thermostat is stuck open.
Monitoring Conditions:
- IAT: 14°F (-10°C) or less
- Difference between ECT at engine start and minimum IAT: 43°F (6°C) or less
- Vehicle speed: 3.7 MPH or more (MTX)
- Vehicle speed: 5.8 MPH or more (ATX)
DTC P0128: PCM monitors MAF, IAT, VSS and ECT signals and calculates radiator heat radiation ratio while the following monitoring conditions are met. If calculated value exceeds the threshold, PCM determines coolant thermostat is stuck open.
Monitoring Conditions:
- ECT at engine start: 97°F (36°C) or less
- IAT: 14°F (-10°C) or more
- Difference between ECT at engine start and minimum IAT: 43°F (6°C) or less
- Vehicle speed: 18.6 MPH or more (MTX)
- Vehicle speed: 12.4 MPH or more (ATX)