CM2150 Electronic Control System – FAULT CODE 2554

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Overview

ISB, ISC, and ISL – Exhaust Gas Pressure 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 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 F.

Conditions for Running the Diagnostics

• This diagnostic runs when the keyswitch is initially turned ON.
• The diagnostic will also run when the engine is running and lower than expected exhaust pressure is detected.

Conditions for Setting the Fault Codes

• The ECM detects that the exhaust pressure reading is higher or lower than the other absolute pressure sensors on the engine when the keyswitch is ON and the engine is not running.
• The ECM detects that the exhaust pressure is lower than a calibratible value during normal engine operation.

Action Taken When the Fault Code is Active

• The ECM illuminates the amber CHECK ENGINE light immediately when the diagnostic runs and fails.
• A default value is used for the exhaust gas pressure reading.

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

At KEY ON, before the engine starts, the sensor readings for intake manifold pressure, barometric air pressure, and exhaust gas pressure are compared to each other. This fault code occurs if the exhaust gas pressure sensor reading is different from the other sensor readings. This check is only done once after the keyswitch is turned ON.

Possible causes of this fault code include:

• A stuck in-range exhaust gas pressure sensor reading
• A high resistance in the exhaust gas pressure sensor signal or return lines
• Plugging or restriction in the exhaust gas pressure sensor tube.

Refer to Troubleshooting Fault Code t05-2554