Circuit DescriptionThe variable geometry turbocharger (VGT) is electronically activated by the VGT actuator. The VGT actuator is a smart device and receives information via the J1939 data link from the primary engine control module (ECM). The VGT actuator performs its own diagnostics and reports malfunctions back to the primary engine ECM, using the J1939 data link. The ECM then decodes the error message and converts it to a fault code. Component LocationThe VGT actuator is located on the turbocharger bearing housing. Conditions for Running the DiagnosticsThis diagnostic runs continuously when the keyswitch is in the ON position or when the...

Circuit DescriptionThe sensor supply 6 circuit of the engine control module (ECM) is a dedicated (+) 5-VDC supply for the fuel rail pressure sensor. Component LocationSensor Supply 6 originates in the Engine Wiring Harness portion of the ECM. It supplies 5 volts to sensors in the engine wiring harness. Conditions for Running the DiagnosticsThis diagnostic runs continuously when the keyswitch is in the ON position or when the engine is running. Conditions for Setting the Fault CodesThe Engine Control Module (ECM) detected the sensor supply 6 signal voltage was greater than 5.2-VDC for more than 1 second. Action Taken When...

Circuit DescriptionThe sensor supply 6 circuit of the engine control module (ECM) is a dedicated (+) 5-VDC supply for the fuel rail pressure sensor. Component LocationSensor Supply 6 originates in the Engine Wiring Harness portion of the ECM. It supplies 5 volts to sensors in the engine wiring harness. Conditions for Running the DiagnosticsThis diagnostic runs continuously when the keyswitch is in the ON position or when the engine is running. Conditions for Setting the Fault CodesThe Engine Control Module (ECM) detected the sensor supply 6 signal voltage was less than 4.8-VDC for more than 1 second. Action Taken When...

Circuit DescriptionThe variable geometry turbocharger (VGT) is electronically activated by the VGT actuator. The VGT actuator is a smart device and receives information via the J1939 data link from the primary engine control module (ECM). The VGT actuator performs its own diagnostics and reports malfunctions back to the primary engine ECM, using the J1939 data link. The ECM then decodes the error message and converts it to a fault code. Component LocationThe VGT actuator is located on the turbocharger bearing housing. Conditions for Running the DiagnosticsThis diagnostic runs continuously when the keyswitch is in the ON position. Conditions for Setting...

Circuit DescriptionThe air shutoff valve position switch is located inside the air shutoff valve. During testing, the engine is accelerated and the air shutoff valve closes at a predetermined engine speed. When the air shutoff valve closes, the position switch closes. The ECM monitors the Air Shutoff Valve Position Signal circuit for a change indicating the switch closed. Component LocationThe air shutoff valve position switch is located inside the air shutoff valve. The air shutoff valve is either an OEM or Cummins® installed component, and is usually located on the air intake connection. Conditions for Running the DiagnosticsThis diagnostic only...