Thermostat Monitor

OBD System Description - Thermostat Monitor

System Description / Monitoring Procedure
The system accumulates the intake air quantity to simulate the engine operating condition as the warm up counter.

The thermostat is considered malfunctioning if the coolant temperature does not reach 75 °C at which the thermostat is at the regulating temperature (82 °C) within 11 °C. The time interval required for monitoring is based on the accumulated intake air quantity.
1. Time interval required for monitoring: Approximately 15 minutes maximum
2. Monitoring condition: engine start ECT=-8 to 65 °C

DTC Description / Detecting Condition / Confirmation Procedure

P0128
Refer to DTC P0128: Coolant Thermostat (Coolant Temperature below Thermostat Regulating Temperature):H27 Engine.

Operation:

Enable Conditions:

Common Prohibition Mode:

Typical Malfunction Thresholds:

Thermostat Monitor