What is the EGR Temperature Sensor all about?

Vehicle manufacturers have been required for decades to lower the level of car emissions. One of the earliest methods of pollution control was the exhaust gas recirculation system, which is still in use by nearly all vehicles today. The exhaust gas recirculation (EGR) system re-introduces partially burned exhaust gases into the intake manifold along with the air/fuel mixture to complete its burn before being expelled out the tailpipe and into the atmosphere.

The EGR valve opens and closes to regulate the amount of exhaust to allow into the intake. The EGR temperature sensor is mounted in the EGR tube and measures the temperature of the exhaust gases entering the EGR valve. The engine control module receives the information from the EGR temperature sensor, determines the correct amount of flow through the EGR valve, and adjusts the valve accordingly. If the EGR temperature sensor isn’t reading properly, the EGR valve will not be open in the correct position. It can cause engine knock, which will cause internal engine damage. The Check Engine light can come on with EGR system-related codes and the emissions from the tailpipe will exceed the maximum standards set by your state’s smog/emissions test.

Keep in mind:

• If the EGR temperature sensor is being replaced, check for proper operation of the EGR valve as well.
• The EGR temperature sensor is extremely hot while the engine is on. Allow the engine to cool before attempting to inspect or service the temperature sensor.

How it's done:

• The EGR temperature sensor is verified that it needs to be replaced. The engine top trim cover is removed.
• The defective EGR temperature sensor is removed by disconnecting the electrical connection and removing the sensor from the EGR base or tube.
• The new EGR temperature sensor is installed into the EGR tube and the electrical connection is reconnected.
• The engine is started and the EGR temperature sensor is tested for operation. The engine trim cover is reinstalled.
• The vehicle is road tested to ensure proper operation of the EGR temperature sensor.

Our recommendation:

The EGR temperature sensor should last the lifetime of your vehicle. It would be advisable to have the EGR system scanned when a smog test is performed, especially if the test fails. If the EGR temperature sensor is reading incorrectly, one of our expert technicians will need to replace it.

What common symptoms indicate you may need to replace the EGR Temperature Sensor?

• Audible engine knock
• Check Engine light is on
• Failed emissions or smog test

How important is this service?

If left unaddressed, the engine knock caused by a faulty EGR temperature sensor will produce internal engine damage which can only be fixed through expensive repairs. You will likely fail a smog test with a faulty EGR temperature sensor. If the EGR temperature sensor fails, have it replaced quickly.