Diagnostic Aids
The Exhaust Gas Recirculation (EGR) actuator is a variable position valve that controls the amount of exhaust that enters the intake manifold. The EGR is controlled by the PCM using a pulse width modulated signal that varies from 0-85 percent. The EGR actuator consists of two components, a valve with actuator (solenoid) and a position sensor to monitor valve movement. The EGR sensor is a potentiometer sensor. When the EGR receives a 5-volt reference signal and a ground from the PCM, a linear analog voltage signal from the sensor will indicate position of the EGR valve.
The PCM will detect an open or short in the EGR control circuit after the KOEO test has run and set a DTC. The EGR actuator can be tested for a stuck or sticking valve by performing an output state low test while monitoring EGR percentage.