Cummins Fault Code 6432

11/12/2025

Overview

CODE

REASON

EFFECT

Fault Code: 6432
PID:
SPN: 641
FMI: 14/14
LAMP: Amber
SRT:

The VGT actuator has been installed incorrectly.

Possible reduced engine performance.

Cummins Fault Code 6432 — VGT Actuator Circuit

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 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 Location

The VGT actuator is located on the turbocharger bearing housing.

Conditions for Running the Diagnostics

This diagnostic runs when the keyswitch is initially turned to the ON position.

The keyswitch must be turned OFF for more than 30 seconds before this diagnostic will run at initial key ON.

Conditions for Setting the Fault Codes

The Variable Geometry Turbocharger (VGT) actuator position was not known during initial power ON.

Action Taken When the Fault Code is Active

The ECM illuminates the amber CHECK ENGINE lamp and/or the malfunction indicator lamp (MIL) immediately when the diagnostic runs and fails.

VGT actuation will be disabled.

Exhaust gas recirculation (EGR) valve operation will be disabled.

Engine torque will be reduced if the engine is operated for an extended period of time with this fault active.

Conditions for Clearing the Fault Code

To validate the repair, perform a key cycle, and leave the keyswitch in the ON position for 1 minute. Note that the keyswitch must be completely turned OFF for more than 30 seconds before this diagnostic will run at initial key ON.
The fault code status displayed by the recommended Cummins electronic service tool or equivalent will change to INACTIVE immediately after the diagnostic runs and passes.
The ECM will turn off the amber CHECK ENGINE lamp and/or MIL immediately after the diagnostic runs and passes.
For On-Board Diagnostics (OBD) engines, the ECM will extinguish the Malfunction Indicator Lamp (MIL) after three consecutive trips where the diagnostic runs and passes.
The “Reset All Faults” command in the recommended Cummins electronic service tool or equivalent can be used to clear active and inactive faults, as well as extinguish the MIL for OBD applications.

Shop Talk

This fault code can only be logged after the VGT actuator has been removed or replaced, and then not installed correctly. The gear alignment between the actuator and the turbocharger housing is misaligned. The correct installation procedure must be followed when replacing the VGT actuator.

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