P0128

DTC P0128 COOLANT THERMOSTAT (ENGINE COOLANT TEMPERATURE BELOW THERMOSTAT REGULATING TEMPERATURE)

1. OUTLINE OF DIAGNOSIS
Detect malfunctions of the thermostat function.
Judge as NG when any one of the following conditions is established.
- Actual engine coolant temperature does not reach the highest temperature which is necessary to perform other OBDII diagnoses. (Judgment 1)
- Actual engine coolant temperature is not within the range of the regulated temperature to -11 °C (-19.8 °F). (Judgment 2)
- Difference between the estimated engine coolant temperature and actual engine coolant temperature exceeds the specified value. (Judgment 3)

2. COMPONENT DESCRIPTION






3. ENABLE CONDITION






4. GENERAL DRIVING CYCLE
Perform the diagnosis only once after starting the engine.

5. DIAGNOSTIC METHOD

- Abnormality Judgment
If the duration of time while the following conditions are met is longer than the time indicated, judge as NG.






Time Needed for Diagnosis: 16 - 30 seconds

Malfunction Indicator Light Illumination: Illuminates when malfunction occurs in 2 continuous driving cycles.

- Normality Judgment
Judge as OK and clear the NG if the continuous time while the following conditions are established is more than the predetermined time.






Time Needed for Diagnosis: Less than 1 second