Monitor Description

Engine coolant temperature sensor cold start monitor 

When a cold engine start is performed and then the engine is warmed up, if the engine coolant temperature sensor value does not change, it is determined that a malfunction has occurred. If this is detected in 2 consecutive driving cycles, the MIL is illuminated and a DTC is set.

Engine coolant temperature sensor soak monitor 

If the engine coolant temperature sensor value does not change after the warmed up engine is stopped and then the next cold engine start is performed, it is determined that a malfunction has occurred. If this is detected in 2 consecutive driving cycles, the MIL is illuminated and a DTC is set.

Examples: 

• Upon starting the engine, the engine coolant temperature is between 35°C and 60°C (95°F and 140°F). If after driving for 250 seconds, the engine coolant temperature remains within 3°C (37.4°F) of the starting temperature, the DTC is set (2 trip detection logic).
• Upon starting the engine, the engine coolant temperature is over 60°C (140°F). If after driving for 250 seconds, the ECM remains within 1°C (33.8°F) of the starting temperature, the DTC is set (6 trip detection logic).