How do coolant temp sensors work?

How the Temperature Sensor Works

1. On most vehicles, the coolant temperature sensor (CTS) can be found somewhere near the engine thermostat, which allows it to function optimally.
2. The sensor works by measuring the temperature that’s being given off by the thermostat and/or the coolant itself.

How can I tell if my coolant temperature sensor is bad?

To diagnose the coolant temperature sensor, you need a repair manual for your car model to find what measurement values you should expect from the coolant temperature sensor. Connect an OBD2 Scanner and look for related trouble codes. Check the live data to see the temperature from the sensor.

What’s the name of the coolant temperature sensor?

Coolant temperature sensors are also known as engine coolant temperature sensors or ECT sensors. The principle working of this sensor involves the use of an electrical resistance which measures the temperature of the coolant.

What should coolant temp be when engine is hot?

With a good OBD2 code reader, you can also check the live data and the parameters of the CTS sensor. Check that the temperature value of the CTS is around 80-90c when the engine is hot. A lot of engine coolant temperature sensors have two wires and the sensor is controlled by Ohm.

How many temperature sensors does a car have?

There may be two temperature sensors in some vehicles, one to send information from the engine system to the control unit and another from the control unit to the dashboard. However, some vehicles dispense with the need for two temperature sensors by using just one sensor to do both tasks.

What is the correct way to check a coolant temperature sensor?

If your vehicle won’t start when cold, the easiest way to check the engine coolant temperature sensor is to depress the gas pedal while cranking the engine. If it starts, that’s a pretty good sign the sensor is off.

What are the symptoms of a bad coolant temperature sensor?

Another symptom of a problem with the coolant temperature sensor is an overheating engine. The coolant temperature sensor can also fail in a manner that causes it to send a permanently hot signal. This can cause the computer to incorrectly compensate for a lean signal, which can result in overheating, and even misfires or engine ping.

What does a bad coolant temperature sensor do?

If the coolant temperature sensor goes bad it can send a false signal to the computer and throw off the fuel and timing calculations. It is not uncommon for the coolant temperature sensor to fail and send a permanently cold signal to the computer.

How much voltage should a coolant temp sensor have?

Engine Coolant Temperature (ECT) Sensor Voltage – Testing. The reference voltage to the sensor from the (PCM) should be about 5-volts . The return voltage signal should be around 3 to 4 volts, when the engine is cold. This should gradually drop to 2 volts or less as the engine reaches, normal operating temperature.