Monitor Description
WARNING: This page is about a different car, the 2025 Toyota GR Corolla, 2024 Toyota GR Corolla, and 2023 Toyota GR Corolla. However, it is still accessible from the selected car via links, so may be relevant.
After the engine has stopped for 5 hours or more, the ECM monitors the voltage of the engine coolant temperature sensor and engine oil temperature sensor. If the difference between the readings of the engine coolant temperature and engine oil temperature is higher than 20°C (36°F), the ECM determines that there is a malfunction in the engine coolant temperature sensor circuit or engine oil temperature sensor circuit, and stores a DTC and illuminates the MIL.