Cummins Fault Code

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SPN 5246 FMI 15

Derate (Speed limited to 5 mph)

System

Aftertreatment

Symptom

Derate (Speed limited to 5 mph)

Diagnosis & fix steps

LOGIC: SCR Operator Inducement Severity - Least Severe. ACTION: Check DEF tank level and quality. Ensure the DEF pump is priming.

Red Seal field insights

Logic: This is the "First Warning." If ignored, it moves to FMI 16. PRO-TIP: Often triggered by a crystallized dosing nozzle.

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