CM871 and CM876 Electronic Control Systems, ISX and ISM Engines – FAULT CODE 1932

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Overview

ISX and ISM – Aftertreatment Fuel Injector System SMALL | MEDIUM | LARGE

Circuit Description

This fault code checks for system errors in the aftertreatment fuel injection system. This diagnostic can detect fuel leaks in the system, as well as a damaged aftertreatment fuel injector, aftertreatment fuel shutoff valve, and aftertreatment fuel drain valve.

Every time the engine is started and prior to active regeneration of the aftertreatment system, a diagnostic test is performed on the system. The aftertreatment fuel drain valve opens and relieves fuel pressure in the line. The aftertreatment fuel pressure sensor must be reading atmospheric pressure at this point in the test. The aftertreatment fuel drain valve closes and the aftertreatment fuel shutoff valve opens. This pressurizes the aftertreatment fuel system to gear pump operating pressure. The diagnostic then checks to make sure the aftertreatment pressure sensor is reading gear pump operating pressure. The aftertreatment fuel shutoff valve then closes and traps the fuel between the aftertreatment fuel shutoff valve and the aftertreatment fuel injector. The diagnostic checks to make sure the system maintains fuel pressure. The aftertreatment fuel drain valve then opens and relieves the remaining pressure in the system.

Component Location

The aftertreatment fuel injector is installed in the exhaust system in the turbocharger outlet flange. The aftertreatment fuel pressure sensor, aftertreatment fuel shutoff valve, and aftertreatment fuel drain valve are installed in the shutoff valve manifold. The aftertreatment shutoff valve is located on the same side of the manifold as the aftertreatment pressure sensor, while the aftertreatment fuel drain valve is located by itself, on the other side of the manifold. Refer to Procedure 100-002 (Engine Diagrams) in Section E for a detailed component location view.

Conditions for Running the Diagnostics

This diagnostic runs during the first minutes of engine operation and before the aftertreatment system begins injecting fuel into the exhaust system for active regeneration of the aftertreatment system.

Conditions for Setting the Fault Codes

The electronic control module (ECM) detects system damage in the aftertreatment fuel system.

Action Taken When the Fault Code is Active

• The ECM will illuminate the amber CHECK ENGINE lamp immediately after the diagnostic runs and fails.
• Active regeneration of the aftertreatment particulate trap will be disabled.

Conditions for Clearing the Fault Code

The ECM will turn off the amber CHECK ENGINE light immediately after the diagnostic runs and passes.

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, calibrate the ECM. Refer to Procedure 019-032 (ECM Calibration Code) in Section 19.

Possible causes of this fault code include:

• Stuck open or closed aftertreatment fuel shutoff valve or aftertreatment fuel drain valve
• Internal or external leak in the aftertreatment fuel shutoff valve or fuel drain valve
• Internal or external leak in the aftertreatment fuel injector
• Loose fittings in the aftertreatment fuel system
• Fuel leaks in the aftertreatment fuel system.

In order to correctly troubleshoot the aftertreatment fuel system, the following INSITE™ electronic service tool ECM tests must
be used. These ECM tests command the aftertreatment fuel injector, aftertreatment fuel shutoff valve, and the aftertreatment fuel drain valve open or closed. The chart below shows how each test operates. It is important to note that the override test stops after 60 seconds, when the “STOP” button is pressed, or when the keyswitch is turned off.

Refer to Troubleshooting Fault Code t05-1932