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.
- When the actual engine coolant temperature does not reach the maximum temperature necessary to perform other OBDII diagnosis and Sigma (Estimated engine coolant temperature - actual engine coolant temperature) exceeded the predetermined value. (Judgment 1)
- When the actual engine coolant temperature does not reach the range within -11 °C (-19.8 °F) from the regulated temperature and Sigma (Estimated engine coolant temperature - actual engine coolant temperature) exceeded the predetermined value. (Judgment 2)
- When the difference between the estimated coolant temperature and the actual engine coolant temperature exceeds the predetermined value, and Sigma (Estimated engine coolant temperature - actual engine coolant temperature) exceeded the predetermined 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: 300 -- 700 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: 300 -- 700 seconds