CM871 and CM876 Electronic Control Systems, ISX and ISM Engines – FAULT CODE 2764

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Overview

ISX – Exhaust Gas Pressure Sensor Circuit SMALL | MEDIUM | LARGE

ISM – Exhaust Gas Pressure Sensor Circuit SMALL | MEDIUM | LARGE

Circuit Description

The exhaust gas pressure sensor is used to measure exhaust gas pressure in the exhaust manifold. This information is used by the electronic control module (ECM) to control emissions and exhaust gas recirculation (EGR) valve operation. The ECM provides a 5 volt supply to the exhaust gas pressure sensor on the sensor supply circuit. The ECM also provides a ground on the sensor return circuit. The exhaust gas pressure sensor provides a signal to the ECM on the exhaust gas pressure sensor signal circuit. This sensor signal voltage changes, based on the pressure in the exhaust manifold.

Component Location

The exhaust gas pressure sensor is located above the front section of the exhaust manifold and is plumbed into the exhaust manifold. Refer to Procedure 100-002 in Section E.

Conditions for Running the Diagnostics

This diagnostic runs continuously when engine speed is greater than 500 rpm.

Conditions for Setting the Fault Codes

This fault code is logged when the exhaust gas pressure sensor is reading a value above the engine protection limits.

Action Taken When the Fault Code is Active

• The fault code is set active immediately when the exhaust gas pressure is above the engine protection limits.
• The ECM illuminates the amber check engine light immediately after the diagnostic runs and fails.
• An engine RPM derate is issued by the ECM.

Conditions for Clearing the Fault Code

The ECM will disable the fault code immediately after the diagnostic runs and passes.

Shop Talk

Verify the 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 in Section 19.

Possible causes of this fault code include:

• Malfunctioning variable geometry turbocharger
• Damaged in-range exhaust gas pressure sensor
• Plugged or restricted aftertreatment diesel particulate filter
• Plugged or restricted EGR cooler
• Exhaust gas pressure sensor connector water intrusion.

Refer to Troubleshooting Fault Code t05-2764