Cummins ISX11.9 CM2250 (2010-12) Fault Code: 2636 PID: SID 27 SPN: 641 FMI: 9 VGT Actuator Driver Circuit- Abnormal Update Rate

Circuit Description
The variable geometry turbocharger (VGT) is electronically activated by the VGT actuator. The VGT actuator is a smart device that receives information via the J1939 data link from the primary engine electronic control module (ECM). The VGT actuator performs its own diagnostics and reports malfunctions back to the primary engine ECM, using the J1939 data link.

Component Location
The VGT actuator is located on the turbocharger bearing housing.

Conditions for Running the Diagnostics
This diagnostic runs continuously when the keyswitch is in the ON position or when the engine is running.

Conditions for Setting the Fault Codes
The primary engine ECM does not receive a valid J1939 message from the VGT actuator for more than 1 second.

Action Taken When the Fault Code is Active
The ECM illuminates the red STOP ENGINE lamp and/or Malfunction Indicator Lamp (MIL) immediately when the diagnostic runs and fails.
The VGT will move to the default open position.
Conditions for Clearing the Fault Code
To validate the repair, start the engine and let it idle for 1 minute
The fault code status displayed by INSITE? electronic service tool will change to INACTIVE immediately after the diagnostic runs and passes.
The ECM will turn off the red STOP ENGINE lamp after the diagnostic runs and passes.
For OBD engines, the ECM will turn off the MIL after three consecutive trips where the diagnostic runs and passes
The ?Reset All Faults? command in INSITE? electronic service tool can be used to clear active and inactive faults, as well as extinguish the MIL for OBD applications.

Shop Talk
Troubleshoot high inactive counts of Fault Code 2636 as an active fault code.

Possible causes of this fault code include:

The VGT actuator is not receiving power from the ECM. This can be caused by an open circuit in the power supply wire or low voltage supplied by the primary engine ECM.
Rapid cycling of the keyswitch
An open return circuit on the VGT actuator circuit
An open or short circuit on the J1939 data link circuit between the ECM and VGT actuator
Intermittent communications between the VGT actuator and the primary engine ECM on the J1939 data link
A damaged termination resistor in the engine data link harness
A malfunctioning engine ECM.

Possible Cause:
1) OEM wiring harness
2) Intake NOx sensor failure
3) VGT Actuator failure
4) Engine wiring harness
5) OEM terminating resistor failure
6) ECM calibration