CM2150 Electronic Control System – FAULT CODE 1896

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Overview

ISB, ISC, and ISL – EGR Valve Circuit SMALL | MEDIUM | LARGE

Circuit Description

The exhaust gas recirculation (EGR) valve is opened by a motor located on top of the EGR valve. A pin is extended from the motor and contacts the dual-poppet valve to open the EGR valve. The EGR valve motor is not used to close the EGR valve. The pin retracts and a spring is used to close the EGR valve.

Component Location

The EGR valve location can vary, depending on the engine application. Refer to Procedure 100-002 (Engine Diagrams) in Section E for a detailed component location view.

Conditions for Running the Diagnostics

This diagnostic runs continuously when the keyswitch is in the ON position or when the engine is running.

Conditions for Setting the Fault Codes

The EGR valve motor measures the position of the EGR valve at initial key-on. If the valve is detected to be greater than 20 percent open, the fault code is set active.

Action Taken When the Fault Code is Active

• The ECM illuminates the amber CHECK ENGINE light immediately when the diagnostic runs and fails.
• The EGR valve will stop responding to commands and the spring will close the EGR valve.

Conditions for Clearing the Fault Code

The ECM will turn off the amber CHECK ENGINE light and clear the fault code after the keyswitch is cycled and 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. Refer to Procedure 019-032 (ECM Calibration Code) in Section 19 in the corresponding Troubleshooting and Repair Manual for the engine being serviced.

When the keyswitch is initially turned on and at various times during engine operation, the closed position of the EGR valve is checked. This diagnostic checks to make sure the EGR valve is not stuck open.

This fault code is logged when the following error conditions exist:

• The EGR valve motor measures the position of the EGR valve at initial key-on. If the valve is detected to be out of the normal position, this fault code will be logged.
• The EGR valve will close when the fault code is active.
• The fault code will remain active until the next key cycle.

The fault code will only go inactive if the initial key-on EGR position check passes.

The aftertreatment system must be inspected after making the appropriate repair outlined in this fault code troubleshooting tree. Progressive damage to the aftertreatment system may have occurred. Perform the Snap-Acceleration Test to check for a malfunctioning diesel particulate filter.

• Refer to Procedure For ISB engines, 014-013 (Aftertreatment Testing) in Section 14 in the ISB Series 6.7L Engines (CM2100 and CM2150 Common Rail Fuel Systems) Service Manual, Bulletin 4021578, for aftertreatment reuse guidelines.
• Refer to Procedure For the ISC and ISL engines, 014-013 ( Aftertreatment Testing) in Section 14 in the ISC and ISL CM2150 Service Manual, Bulletin 4021569, for aftertreatment reuse guidelines.

Refer to Troubleshooting Fault Code t05-1896