CM871 and CM876 Electronic Control Systems, ISX and ISM Engines – FAULT CODE 2345

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Overview

ISX – Turbocharger 1 Speed Circuit SMALL | MEDIUM | LARGE

ISM – Turbocharger 1 Speed Circuit SMALL | MEDIUM | LARGE

Circuit Description

The turbocharger speed sensor is a variable reluctance speed sensor. It consists of a coil of wire and an iron core. The target on the turbocharger shaft is a ground flat in the center of the shaft. As the flat on the turbocharger shaft passes the speed sensor, a signal is generated. The electronic control module (ECM) interprets this signal and converts it to a turbocharger speed reading.

Component Location

The turbocharger speed sensor is located in the center housing of the turbocharger. Use the following procedure for a detailed component location view. Refer to Procedure 100-002 in Section E.

Conditions for Running the Diagnostics

This diagnostic runs continuously when the engine is running.

Conditions for Setting the Fault Codes

The ECM detects that the turbocharger speed has increased faster than physically achievable by the turbocharger.

Action Taken When the Fault Code is Active

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

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, recalibrate the ECM. Use the following procedure in the appropriate Troubleshooting and Repair Manual for the engine being serviced.Refer to Procedure 019-032 in Section 19.

This fault becomes active if the engine is running and the turbocharger speed signal rapidly changes faster than the capabilities of the turbocharger. This fault code can be caused by an intermittent turbocharger speed sensor connection, incorrect turbocharger speed sensor air gap, or a faulty turbocharger speed sensor.

Refer to Troubleshooting Fault Code t05-2345