EGR Temperature Sensor: Description and Operation

OPERATION
The Exhaust Gas Recirculation (EGR) temperature sensor converts the temperature of EGR gas downstream from the EGR valve to voltage and inputs it to the engine control module. The engine control module judges the condition of the EGR by this signal If there is abnormal condition, the check engine/malfunction indicator lamp is turned on to notify the driver.

Five volt power supply in the engine control module is applied to the EGR temperature sensor through the resistance in the module. This power supply further passes through the EGR temperature sensor, which is a kind of a resistor, and is grounded at the engine control module The resistance of the EGR temperature sensor is characterized by a decrease in resistance with an increase of EGR temperature due to increase in quantity of EGR.

EGR temperature sensor terminal voltage increases or decreases with EGR temperature sensor resistance. Therefore, EGR temperature sensor terminal voltage changes with EGR gas temperature. The higher the EGR gas temperature, the lower the EGR temperature sensor terminal voltage.