VGT Actuator Driver Circuit – Abnormal Update Rate
|Fault Code: 2636
VGT Actuator Driver Circuit – Abnormal Update Rate. No communications on the J1939 data link between the engine ECM and the smart VGT controller.
The VGT will move to the default open position.
ISB, ISC, and ISL – VGT Actuator Circuit
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.
The VGT actuator is located on the turbocharger bearing housing. Refer to Procedure 100-002 in Section F.
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 light immediately when the diagnostic runs and fails.
- The VGT will move to the default open position.
Conditions for Clearing the Fault Code
The ECM will turn off the red STOP ENGINE light and enable VGT operation immediately after a valid J1939 message is received from the VGT actuator.
Verify the electronic control module (ECM) calibration is correct. Check the calibration revision history found on QuickServe™ Online for applicable fixes to the calibration stored in the ECM. If necessary, calibrate the ECM again. Refer to Procedure 019-032 in Section 19.
This fault code is logged when the primary engine ECM does not receive valid J1939 information from the VGT actuator.
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 could be caused by an open circuit in the power supply wire or low voltage supplied by the primary engine ECM
- 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
- Rapid cycling of the keyswitch
- Connector pins are not installed in the appropriate locations specified by the wiring diagram.
- A damaged termination resistor in the engine data link harness
- A damaged engine ECM.
The aftertreatment system must be inspected after making the appropriate repair outlined in this fault code troubleshooting tree. Progressive damage to the aftertreatment system may have occurred. Use the following procedures to perform the aftertreatment initial check procedure to test for a damaged diesel particulate filter. Refer to Procedure 014-013 in Section 14, in the ISB CM2150 Service Manual, Bulletin 4021578. Refer to Procedure 014-013 in Section 14, in the ISC and ISL CM2150 Service Manual, Bulletin 4021569.