EGTSensor

Exhaust Gas Temperature Sensor (EGT)

Group: Emissions and exhaust

The EGT sensor measures exhaust gas temperature. It protects the turbocharger and the catalytic converter from overheating and, on diesels, controls regeneration of the diesel particulate filter (DPF).

Contents

What does the EGT sensor do?

It is a resistance thermometer (PT200) or a thermocouple able to measure above 900 °C (1,650 °F). The computer reduces power or enriches the mixture if the temperature gets too high, and diesels use several EGT sensors (before the turbo, before the catalyst and before the DPF) to know when filter regeneration starts and ends.

Where is it located?

Screwed into the exhaust manifold or pipe: before the turbo, before the catalytic converter, or before and after the DPF, depending on the system.

Signal type and reference values

  • 2 wires. PT200 resistance thermometer: about 200 ohms at 0 °C, rising with temperature (about 580 ohms at 500 °C).
  • Approximate exhaust temperatures: 150 to 300 °C at idle, 500 to 700 °C under load, over 600 °C during DPF regeneration.

Values are a guide only: always check the manufacturer's data for your engine.

Symptoms of a bad EGT sensor

  • DPF regenerations that never finish.
  • Limp mode with loss of power.
  • On some diesels, the cooling fan keeps running after the engine is shut off.
  • Codes P0544 to P0549 and P2031 to P2035.

How to test the EGT sensor step by step

  1. With the engine cold, every EGT sensor should read close to the ambient temperature.
  2. A fixed, very high or very low reading points to an open or shorted circuit.
  3. Measure the sensor resistance at room temperature and compare it with the manufacturer's chart.
  4. Check the wiring near the exhaust: the heat burns it easily.

Trouble codes related to the EGT sensor

Frequently asked questions about the EGT sensor

What is the EGT sensor for on a diesel?
To control and protect particulate filter regeneration: the computer needs the exact exhaust temperature to burn off the soot without damaging the filter.
Can the EGT sensor be deleted?
It is not recommended, and in many countries it is illegal: it affects emissions control and the protection of the turbo and the catalyst.

Updated September 25, 2026. Values are a guide only: always confirm them in the service manual for your engine.

Other sensors