The EGR drive module is supplied 12 V to Pin 1 from the ECM main power relay through Pin 10 of the 12-pin
connector. Ground is supplied to Pin 2 from battery ground through Pin 4 of the 12-pin connector.
The ECM sends the desired position to the EGR drive module across the CAN 2 datalink. CAN 2 positive
is ECM Pin X2-6 to EGR drive module Pin 3. CAN 2 negative is ECM Pin X2-13 to EGR drive module Pin 4.
The EGR drive module provides a 9 V supply to the IC from Pin 12 to Pin 1 of the EGR actuator. The EGR drive module provides ground to the IC from Pin 16 to Pin 5 of the EGR actuator. The IC in the EGR actuator produces the following valve position signals:
• Position U – EGR actuator Pin 4 to EGR drive module Pin 13
• Position V – EGR actuator Pin 3 to EGR drive module Pin 14
• Position W – EGR actuator Pin 2 to EGR drive module Pin 15
Depending on desired valve position from the ECM signal and position feedback signal from the IC, the EGR drive module drives the 3 phase DC motor to move the valve to the proper position using the following pulse width modulated signals:
• Motor U – EGR drive module Pin 6 to EGR actuator Pin 8
• Motor V – EGR drive module Pin 7 to EGR actuator Pin 7
• Motor W – EGR drive module Pin 8 to EGR actuator Pin 6
The EGR drive module provides two shields to suppress electrical noise. One shield is for the CAN 2 datalink (EGR drive module Pin 5). The other shield is for the valve position sensor signals used by the EGR drive module to monitor position (EGR drive module Pin 9).
Fault Detection / Management
The EGR drive module constantly monitors the EGR actuator. When an EGR control error is detected,
the EGR drive module sends a message to the ECM, a DTC is set, and the amber ENGINE lamp is illuminated.
EGR Diagnostic Trouble Codes (DTCs)
DTCs are read using the Electronic Service Tool (EST) or by counting the flashes from the amber and red ENGINE lamp.
DTC 163
EGRP signal fault
• DTC 163 is set by the ECM when the EGR drive module detects a position signal failure.
• DTC 163 can be set due to an open or short to ground on the position sensor signal power supply circuit, an open ground circuit, an open or short to ground on any of the position signal circuits, or a failed IC.
• When DTC 163 is active the amber ENGINE lamp is illuminated.
DTC 365
EGR actuator fault detected
• DTC 365 is set by the ECM when the EGR drive module detects an EGR actuator fault.
• DTC 365 can be set due to an open, short to ground, short to a power source on any of the motor signal circuits, failure of EGR actuator motor, or a stuck valve assembly.
• When DTC 365 is active the amber ENGINE lamp is illuminated.
DTC 368
EGR drive module/ECM communication fault
• DTC 368 is set by the ECM when CAN 2 datalink communications are not received from EGR drive module.
• DTC 368 can be set for the EGR drive module due to the following conditions:
If engine starts and runs, the DTC is specific to the EGR drive module and ECM communications.
The following are possible causes:
– An open or short to ground on the power circuit exists.
– An open or short to power on the ground circuit exists.
– CAN 2 positive and CAN 2 negative are both open or high resistance exists.
When CAN communication is not present from the EGR drive module, the ECM sends 100 percent EGR position to the EST. If a no start condition exists with DTC 368 and 543 active, check the CAN 2 wiring (EGR to ECM and
IDM to ECM). See “ECM / IDM Communications” (page 373). One of the CAN 2 datalink wires (CAN 2 positive or negative) is open, short to ground, or short to power exists.
• When DTC 368 is active the amber ENGINE lamp is illuminated.
Tools
• EST with MasterDiagnostics® software
• EZ-Tech® interface cable
• Digital Multimeter (DMM)
• EGR Valve Breakout Harness
• 12–pin Breakout Harness
• Breakout Box
• Terminal Test Adapter Kit
