Cummins X15 CM2450 X124B (2018 & Newer) Fault Code: 6656 PID: SPN: 5842 FMI: 14 SCR Monitoring System Malfunction- Special Instructions

Circuit Description
The ECM continuously monitors the engine’s fault code status to determine if any fault codes critical to successful engine operation are active.

Component Location
The ECM mounting location varies, depending on the engine model, and may be mounted either on or off the engine.

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 Engine Control Module (ECM) detected certain critical fault codes related to engine operation were active and the engine continued to operate.

Action Taken When the Fault Code is Active
The ECM logs the fault code immediately when the diagnostic runs and fails.
Conditions for Clearing the Fault Code
This fault code will go inactive once all other active fault codes have been addressed. Refer to the appropriate fault code troubleshooting tree.

Shop Talk
This fault code is for information only, and indicates that an engine speed derate has been implemented in order to make sure that the critical SCR related fault codes that are presently active in the ECM are addressed as quickly as possible.

Possible Cause:
1) ECM calibration