CM871 and CM876 Electronic Control Systems, ISX and ISM Engines – FAULT CODE 1896

EGR Valve Controller – Out of Calibration


Fault Code: 1896
PID: S146
SPN: 2791
FMI: 13/13
LAMP: Amber

EGR Valve Controller – Out of Calibration. The EGR valve has failed the automatic calibration procedure at initial key ON.

EGR valve actuation will be disabled.

ISX CM871 – EGR Valve Circuit
ISM CM876 – EGR Valve Circuit

Circuit Description

The exhaust gas recirculation (EGR) valve is a smart device and receives commands from the engine electronic control module (ECM) via the J1939 data link. The EGR valve performs its own internal diagnostics and reports failures back to the primary engine ECM using the J1939 data link.

The 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. Use the following procedure for a detailed component location view. Refer to Procedure 100-002 in Section F.

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 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.

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 ECM calibration contains an automatic EGR valve override test 30 seconds after turning the keyswitch ON. The EGR valve will be commanded open to 60 percent and will be held in this position for 1 minute and then it will be commanded to 0 percent open. Turn the keyswitch OFF for 20 seconds and then turn the keyswitch ON and read the fault codes. If Fault Code 1896 is active, this indicates the EGR valve is stuck in the open position.

The fault code will only become 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 damaged diesel particulate filter. Use the following procedure in the ISM, ISMe, and QSM11 Service Manual, Bulletin 3666322, or the Signature, ISX and QSX15 Service Manual, Bulletin 3666239, for aftertreatment reuse guidelines. Refer to Procedure 014-013 in Section 14.

Refer to Troubleshooting Fault Code t05-1896.

Last Modified:  03-Dec-2010