The 2.3L engine incorporates a stepper motor-controlled EGR valve which receives its signal from the Powertrain Control Module (PCM). Engine coolant is used to cool the EGR valve. The EGR valve and stepper motor are serviced as an assembly.3.0L And 4.0L Engines
The Differential Pressure Feedback EGR (DPFE) sensor is a ceramic, capacitive-type pressure transducer that monitors the differential pressure across a metering orifice located in the orifice tube assembly. The DPFE sensor receives this signal through 2 hoses referred to as the downstream pressure hose (REF SIGNAL) and upstream pressure hose (HI SIGNAL). The HI and REF hose connections are marked on the differential pressure feedback EGR sensor housing for identification (note that the HI signal uses a larger diameter hose). The DPFE sensor outputs a voltage proportional to the pressure drop across the metering orifice and supplies it to the PCM as EGR flow rate feedback.
The PCM controls the EGR vacuum regulator solenoid. The EGR vacuum regulator solenoid controls the vacuum to the EGR valve. When the EGR valve opens, exhaust gas flows to the intake manifold to be returned to the combustion cycle. The differential pressure feedback EGR system monitors the flow and returns a signal to the PCM.
The amount of recirculated exhaust gas depends upon:
Removal & Installation
3.0L And 4.0L Engines
- Disconnect the negative battery cable.
- Disconnect the pushpin retainer from the Differential Pressure Feedback EGR (DPFE) sensor.
- Disconnect the DPFE sensor electrical connector.
- Remove the DPFE sensor from the hoses.
- To install, reverse the removal procedure.
3.0L And 4.0L Engines
Disconnect the DPFE sensor harness connector. With the ignition on and engine off, measure the voltage between VREF and SIGRTN terminals of the DPFE harness connector. If the voltage is 4 -5.5V, the power circuits to the sensor are okay.
NOTETypical sensor voltage with no EGR flow is between 0.25 volt and 1.3 volts. A higher voltage at idle may be due to a non-seating or heavily carboned EGR valve pintle. DPFEGR PID voltage must increase as the valve opens and decrease as the valve closes. A slow return voltage is an indication of a binding or slow closing EGR valve.