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# What is the ECT sensor for?

## What is the ECT sensor for?

A coolant temperature sensor (CTS) (also known as an ECT sensor or ECTS (engine coolant temperature sensor) is used to measure the temperature of the coolant/antifreeze mix in the cooling system, giving an indication of how much heat the engine is giving off.

## How does the ECT sensor work in a car?

The engine coolant temperature sensor, also known as the ECT sensor, is a negative temperature coefficient thermistor – meaning, the electrical resistance goes down, while the temperature rises. When a signal from the ECT sensor is missing or it is outside of the expected range, the powertrain control module turns on the check engine light.

What does the coolant temperature sensor ( ECT ) do?

The engine coolant temperature sensor is temperature-variable resistor, which usually has a negative temperature coefficient. It is a two-wire thermistor immersed in coolant and measures its temperature. The onboard computer uses the signal of ECT as the main correction factor when calculating the ignition advance and the injection duration.

What is the resistance of an ECT sensor?

The ECT sensor is shown on fig. 1. Fig. 1 In order to convert the ECT resistance variation to voltage variation, which is further processed by the ECU, the ECT sensor is connected in a circuit typically supplied with a reference voltage of +5V. In cold engine and an ambient temperature of 20 ºC the sensor resistance is between 2000Ω and 3000Ω.

### What should the ECT be when the engine is warm?

Start the engine and warm it to the operating temperature. During engine warming the voltage should decrease in accordance with the values given in Table-1. Common problem is that the output resistance (and voltage) changes incorrectly beyond its normal range. The normal value of the ECT sensor voltage is 2V at cold engine and 0.5V at warm engine.

The engine coolant temperature sensor, also known as the ECT sensor, is a negative temperature coefficient thermistor – meaning, the electrical resistance goes down, while the temperature rises. When a signal from the ECT sensor is missing or it is outside of the expected range, the powertrain control module turns on the check engine light.

### What should the resistance of an ECT sensor be?

Check your vehicle service manual for the correct resistance value for your ECT sensor. However, not all service manuals have this information. Most sensors of this type have a resistance value of 3000 ohms or more at about 55F (13C).

How does the CHT sensor work in a car?

The CHT sensor works similar to the ECt sensor, but it measures the cylinder head metal temperature. This allows the CHT sensor to measure the engine temperature correctly, even if the coolant is leaking.

How does a coolant sensor work in an engine?

The (ECT) sensor, is an engine management system sensor; that is used to monitor the temperature of the engine’s coolant. The tip of the (ECT) sensor protrudes into one of the cooling system passages; and is immersed in coolant. Most (ECT) sensors operate using electrical resistance, to measure the temperature of the coolant.

Ruth Doyle