Impreza Wagon AWD F4-1820cc 1.8L SOHC (1993)
EGR Temperature Sensor: Description and Operation
PURPOSE
The EGR temperature sensor (CA only) senses exhaust gas being recirculated into the engine. The sensor is used for diagnosis of the EGR system.
LOCATION
Threaded into the EGR passage on the intake manifold.
OPERATION
Whenever the ignition is ON, the sensor signal is available. When the EGR valve is open, and exhaust is flowing into the engine, the sensor reads
high temperature. When the EGR is closed, it reads low temperature. Because the ECU triggers the EGR through a solenoid, it is able to determine
if the EGR is responding to it's control.