CM2150 Electronic Control System – FAULT CODE 2639

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Overview

ISB, ISC, and ISL – Aftertreatment System SMALL | MEDIUM | LARGE

Circuit Description

The engine aftertreatment system monitors the soot load in the aftertreatment diesel particulate filter. Under normal operating conditions, the aftertreatment diesel particulate filter is self-cleaning, where soot is converted to carbon dioxide, nitrogen, and water. Under light load operating conditions, it can be necessary to perform a stationary regeneration of the aftertreatment diesel particulate filter. The soot load in the aftertreatment diesel particulate filter is estimated, using the aftertreatment differential pressure sensor and the calculated soot output of the engine.

This fault code can be triggered if the application is not operating at a duty cycle high enough to regenerate the aftertreatment diesel particulate filter. This fault code indicates that the exhaust temperatures exiting the turbocharger are not high enough to actively regenerate the soot that is trapped in the aftertreatment diesel particulate filter. It may be necessary to increase the duty cycle of the application in order to prevent plugging of the aftertreatment diesel particulate filter.

Component Location

The aftertreatment diesel particulate filter is located in the exhaust system and is installed by the original equipment manufacturer (OEM). Refer to the OEM troubleshooting and repair manual.

Conditions for Running the Diagnostics

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

Conditions for Setting the Fault Codes

The electronic control module (ECM) detects that the soot load of the aftertreatment diesel particulate filter is above normal – least severe. The aftertreatment system needs to be regenerated to remove the soot.

Action Taken When the Fault Code is Active

• The ECM will illuminate the aftertreatment diesel particulate filter lamp immediately after the diagnostic is set.
• The ECM will flash the aftertreatment diesel particulate filter lamp as the severity of the soot load increases.
• A mild torque derate will be applied to the output of the engine after the aftertreatment diesel particulate filter lamp begins to flash. (Note: There is no derate in emergency vehicle calibrations.)

Conditions for Clearing the Fault Code

The ECM will turn off the aftertreatment diesel particulate filter lamp immediately after the soot load in the aftertreatment diesel particulate filter has dropped below the least severe level.

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 in Section 19 in the corresponding Troubleshooting and Repair Manual for the engine being serviced.

Note: This fault code indicates that the aftertreatment diesel particulate filter requires maintenance by performing a stationary regeneration procedure. This is a maintenance procedure only and is not covered by Cummins Inc. warranty.

Note: Repeated occurrences of this fault code may indicate the engine requires frequent regeneration. Refer to symptom tree t147 (Aftertreatment Diesel Particulate Filter-Excessive Automatic and/or Stationary Regeneration) to identify the cause of frequent regeneration.

Possible causes of this fault code include:

• The engine has been operating in light load operating conditions that prevent exhaust temperatures from being high enough to regenerate the aftertreatment diesel particulate filter
• Possible engine damage that causes excessive black smoke to be generated.

The aftertreatment diesel particulate filter soot loading can be classified into four different stages. As the soot load increases, the aftertreatment diesel particulate filter lamp and the Cummins CHECK ENGINE (Amber) or STOP ENGINE (Red) lamp will operate according to the table below. Inadequate temperature for the exhaust gases entering the aftertreatment system can be a cause of high soot loads in the aftertreatment diesel particulate filter. The duty cycle of the application will need to be increased in order to prevent excessive soot from accumulating in the filter.

Refer to Troubleshooting Fault Code t05-2639.