Cummins Fault Code
Free · no signupCummins 3712 (SPN:5246 / FMI:0)
Final Derate / 5 MPH Limit.
System
Aftertreatment
Symptom
Final Derate / 5 MPH Limit.
Diagnosis & fix steps
LOGIC: Regulatory Inducement—SCR system failure has been ignored for too long.
ACTION: Resolve the "root cause" code (e.g., DEF quality or NOx sensor) and perform a "Stationary Regeneration" or "SCR Crystalization Reset."
Red Seal field insights
Red Seal Fix: You cannot "clear" this code by just unhooking the batteries. The ECM has a timer that must be satisfied. Usually, you need to fix the secondary fault (like SPN 6254) and then run the engine at high exhaust temps to prove the SCR is working again.
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