International DT466 – ELECTRONIC CONTROL SYSTEMS DIAGNOSTICS – EGR Actuator (Exhaust Gas Recirculation)

The function diagram for the EGR actuator includes the following:
• Electronic Control Module (ECM)
• Variable Geometry Turbocharger (VGT) actuator
• Accelerator Position Sensor (APS)
• EGR actuator with position sensors
• EGR drive module
• Exhaust Back Pressure (EBP) sensor
• Manifold Absolute Temperature (MAT) sensor
• Barometric Absolute Pressure (BAP) sensor

• Engine Coolant Temperature (ECT) sensor
• Engine Oil Temperature (EOT) sensor
• Manifold Absolute Pressure (MAP) sensor
• ENGINE lamp (amber)

The EGR actuator consists of three major components, a valve, an actuator motor, and Integrated Circuit (IC). The IC has three Hall effect position sensors to monitor valve movement. The EGR actuator is located at the front of the engine on the mixer duct.

The EGR drive module controls the EGR actuator and is located on the left side of the engine on the ECM
and Injector Driver Module (IDM).
The EGR actuator is a variable position valve that controls the amount of exhaust entering the intake system.
The ECM uses sensor input from the BAP, EBP, MAT, MAP, APS, EOT, ECT, and VGT control to calculate the desired position of the EGR actuator. The EGR drive module receives the desired EGR actuator position from the ECM across the CAN 2 datalink to activate the valve for exhaust gas recirculation. The EGR drive module provides
feedback to the ECM on the valve position. The EGR drive module interprets the ECM command and sends the command using three pulse width modulated signals to the valve actuator.

The system is closed loop control using the EGR position signals. The EGR drive module provides a 9 V supply and ground to the IC in the motor of the valve. When the EGR drive module directs the valve to move, the IC with three Hall effect sensors provides the EGR drive module with the valve position signals.
The EGR drive module interprets the three signals to determine valve position and sends the information back to the ECM.