CM871 and CM876 Electronic Control Systems, ISX and ISM Engines – FAULT CODE 1962

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Overview

ISX – VGT Actuator Circuit SMALL | MEDIUM | LARGE

ISM – VGT Actuator Circuit SMALL | MEDIUM | LARGE

Circuit Description

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

Component Location

The VGT actuator is located on the turbocharger bearing housing. Refer to Procedure 100-002 (Engine Diagrams) in Section E for a detailed component location view.

Conditions for Running the Diagnostics

The diagnostic runs continuously when the keyswitch is turned on.

Conditions for Setting the Fault Codes

The fault code will log when the internal temperature of the VGT actuator exceeds 125°C [257°F] continuously for 30 minutes.

Action Taken When the Fault Code is Active

• The ECM illuminates the amber CHECK ENGINE light immediately when the diagnostic runs and fails.

Conditions for Clearing the Fault Code

The ECM will turn off the amber CHECK ENGINE light immediately after the internal actuator temperature drops below 125°C [257°F].

Shop Talk

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, recalibrate the ECM. Refer to Procedure 019-032 (ECM Calibration Code) in Section 19 in the corresponding Troubleshooting and Repair Manual for the engine being serviced.

The fault code will log when the internal temperature of the VGT actuator exceeds 125°C [257°F].

This fault code will be inactive when the vehicle is in the shop because the VGT actuator temperature has cooled down.

Troubleshoot multiple inactive counts of this fault code as an active fault code.

Also check for exhaust leaks blowing on the VGT actuator. Repair any exhaust leaks.

Refer to Troubleshooting Fault Code t05-1962