| DESCRIPTION |
Thermostat stuck open |
| DETECTION CONDITION |
Determination conditions |
- Actual engine coolant temperature does not exceed 77 °C {171 °F} even though the estimated engine coolant temperature after the engine is started exceeds 77 °C {171 °F}.
|
| Preconditions |
- Engine coolant temperature after engine start: 77 °C {171 °F} or less
- If the following condition is implemented 3 times or more.
- Vehicle is driven for approx. 35.9 s at a speed of 40 km/h {25 mph}, and engine coolant heat radiation amount is frequently at 240 W/K or more compared to 240.01 W/K or less
- The actual engine coolant temperature is 18.9 °C {66 °F} higher than the estimated ambient temperature calculated by the PCM based on the values input.
- Intake air temperature: -10-45 °C {14-113 °F}
- Engine coolant temperature at engine start: -10-58 °C {14-136 °F}
- Vehicle speed: 140 km/h {87 mph} or less
- Engine speed: 5, 400 rpm or less
- Idle ratio: 50 % or less
- The following DTCs are not detected:
- Fuel system malfunction: P0171:00, P0172:00, P2096:00, P2097:00
- ECT sensor malfunction: P0117:00, P0118:00
- MAF sensor malfunction: P0102:00, P0103:00
|
| Drive cycle |
|
| Self test type |
|
| Sensor used |
- Desired engine coolant temperature: intake air temperature (IAT sensor), engine speed (CKP sensor), charging efficiency
- Actual engine coolant temperature: ECT sensor
|
| FAIL-SAFE FUNCTION |
|
| VEHICLE STATUS WHEN DTCs ARE OUTPUT |
- Illuminates check engine light.
- Heating is ineffective after engine is started
|
| POSSIBLE CAUSE |
- ECT sensor malfunction
- Poor assembly of ECT sensor
- Poor assembly of engine coolant hose (engine coolant passage malfunction)
- Poor engine coolant, leakage, or freezing
- Use of unspecified engine coolant
- Foreign matter caught in thermostat (foreign matter penetration in engine coolant)
- Thermostat malfunction
- PCM malfunction
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