General Description
Thermostat , installed between engine and radiator, is automatically opened or closed in order to control the amount of flowing water so that ECM matains engine coolant temperature at certain level. If, generally, engine coolant temperature reaches about 80?(176 °F), wax in the thermostat is expended in order to open the valve. And, reversely, if coolant temperature is low, wax in the thermostat is contracted that makes valve is closed. Thermostat maintains engine temperature in order to active best engine performance and prevent overheat and overcooling.
DTC Description
Checking time and coolant temperature under detecting condition, if the coolant temperature dose not reach the target temperature as the test timer reaches the threshold time, ECM sets P0128.
DTC Detecting Condition
Item | Detecting Condition | Possible Cause |
DTC Strategy | Thermostat open stuck monitor
| Thermostat stuck |
Enable Conditions | -7.0?(19.4?) < IAT temp < 57?(134.6?)
-7.0?(19.4?) <ECT temp < 57?(134.6?)
IAT at start - IAT <5.0?(41?)
Low speed drive(< 25mph) ratio driving time < 0.7
|
Threshold value | The coolant temperature dose not reach the target temperature as the test timer reaches the threshold time.
|
Diagnosis Time | -
|
MIL On Condition | 2 Driving Cycles
|