Engine Coolant Temperature Sensor

WARNING: This page is about a different car, the 2018 Land Rover Range Rover, 2017 Land Rover Range Rover, and 2016 Land Rover Range Rover. However, it is still accessible from the selected car via links, so may be relevant.

The Engine Coolant Temperature (ECT) sensor is located in the Exhaust Gas Recirculation (EGR) cooler intake hose, at the front of the engine.

The Powertrain Control Module (PCM) uses the temperature information for the following functions:

Fueling calculations
Limit engine operation if engine coolant temperature becomes too high
Electric cooling fan operation
Glow plug activation time.

The Instrument Cluster (IC) uses the temperature information for generation of engine temperature messages. The ECT signal is also transmitted on the High Speed (HS) Controller Area Network (CAN) chassis systems bus by the IC for use by other systems.

The ECT sensor circuit consists of an internal voltage divider circuit which incorporates a Negative Temperature Coefficient (NTC) thermistor. The PCM compares the signal voltage to stored values and adjusts fuel delivery to ensure optimum driveability at all times.

The input to the sensor is a 5 V reference voltage supplied from the voltage divider circuit within the PCM. The ground from the sensor is also connected to the PCM which measures the returned current and calculates a resistance figure for the sensor which relates to the coolant temperature.

For additional information, refer to: ENGINE COOLING

If the ECT sensor fails, the following symptoms may be observed:

Difficult cold start
Difficult hot start
Engine performance compromised
Temperature gauge inoperative or inaccurate reading.

In the event of ECT sensor signal failure, the PCM applies a default value of 80°C (176° F) coolant temperature for fueling purposes. The PCM will also permanently operate the cooling fan at all times when the ignition is switched on, to protect the engine from overheating.