Monitor Description

WARNING: This page is about a different car, the 2025 Lexus RX 350, 2024 Lexus RX 350, and 2023 Lexus RX 350. However, it is still accessible from the selected car via links, so may be relevant.

Engine Coolant Temperature Sensor (for Cylinder Head Side) Cold Start Monitor

When a cold engine start is performed and then the engine is warmed up, if the engine coolant temperature sensor (for cylinder head side) 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 this DTC is stored.

Engine Coolant Temperature Sensor (for Cylinder Head Side) Soak Monitor

If the engine coolant temperature sensor (for cylinder head side) 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 this DTC is stored.