Cummins Fault Code

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SPN 5246 FMI 0

5-MPH Derate Active.

System

Exhaust

Symptom

5-MPH Derate Active.

Diagnosis & fix steps

LOGIC: Aftertreatment Regulatory Derate. ACTION: Perform a Forced Regen. If it fails, check for a "Face Plugged" DPF.

Red Seal field insights

Specs: Triggered after multiple ignored regens. RED SEAL FIX: If the soot load is low but this code is active, the SCR has failed a "Performance Test." Check DEF quality first.

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