CM871 and CM876 Electronic Control Systems, ISX and ISM Engines – FAULT CODE 1923

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Overview

ISX – Aftertreatment Fuel Shutoff Valve 1 Circuit SMALL | MEDIUM | LARGE

ISM – Aftertreatment Fuel Shutoff Valve 1 Circuit SMALL | MEDIUM | LARGE

Circuit Description

The aftertreatment fuel shutoff valve is used to disable the fuel supply to the aftertreatment system.

Component Location

The aftertreatment fuel shutoff valve sensor is located in the aftertreatment shutoff valve assembly. Refer to Procedure 100-002 (Engine Diagrams) in Section E for a detailed component location view.

Conditions for Running the Diagnostics

This diagnostic runs within the first 30 seconds of the engine starting and prior to active regeneration of the diesel particulate filter.

Conditions for Setting the Fault Codes

The engine fuel shutoff valve circuit pulse width modulated (PWM) signal is detected to be at system voltage when the PWM voltage is turned off.

Action Taken When the Fault Code is Active

• The electronic control module (ECM) illuminates the amber CHECK ENGINE light immediately when the diagnostic runs and fails.
• Active aftertreatment diesel particulate filter regeneration 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.

The fault code will clear within 30 seconds of starting the engine or prior to an active regeneration event of the diesel particulate filter.

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.

Possible causes of this fault code include:

• Open return circuit in the engine harness, connectors, or shutoff valve.
• Fuel shutoff valve signal wire shorted to a voltage source in the harness.
• A damaged aftertreatment fuel shutoff valve.

Refer to Troubleshooting Fault Code t05-1923