The VGT actuator receives power at Pin 1, through the 12-pin connector Pin 10, from the ECM main power
relay Pin 87. Ground for the VGT actuator is supplied at Pin 2, through the 12-pin connector Pin 4 from battery ground. The ECM controls the VGT actuator by sending a pulse width modulated signal from the ECM, Pin X1-18 to the actuator harness connector Pin 3.
The VGT actuator is controlled by varying the percentage of ON/OFF time of the VGT actuator control signal to control module. A high duty cycle indicates a high amount of exhaust back pressure is being commanded. A low duty cycle indicates less pressure being commanded.
Fault Detection / Management
When the engine is running, the ECM can detect if exhaust back pressure equals the desired pressure. When measured exhaust back pressure does not equal the desired pressure, the ECM will ignore the EBP sensor signal and use a preset value based on engine operating conditions.
If the VGT actuator is suspect, use the EST to run the Output State Test Low. See “Diagnostic Software Operation” in Section 3 (page 68). Check crank lever operation during this test.
VGT Diagnostic Trouble Codes (DTCs) There are no specific DTCs relating to the wiring or Output Circuit Check (OCC) for the VGT actuator.
When diagnosing the air management system, VGT wiring and operation can be tested with the following checks.
Tools
• EST with MasterDiagnostics® software
• EZ-Tech® interface cable
• Digital Multimeter (DMM)
• Turbo Breakout Harness
• 12-pin Breakout Harness
• Breakout Box
• Terminal Test Adapter Kit
• 500 Ohm Resistor Harness
