Coolant temperature sensor (BMW X5 E53)

The coolant temperature sensor is a resistor with a negative temperature coefficient, meaning its resistance decreases as the temperature increases.

During engine warm-up, the ECU-KSUD ensures enrichment of the fuel mixture based on an electrical signal coming from the temperature sensor installed in the cylinder head.

If the engine does not start, starts with difficulty or stalls after starting, as well as with increased fuel consumption and CO content in the exhaust gas, it is necessary to check the serviceability of the coolant temperature sensor.