Cummins Fault Code
Free · no signupSPN 3216 FMI 3
SCR Engine Derate / MIL On
System
Emissions
Symptom
SCR Engine Derate / MIL On
Diagnosis & fix steps
LOGIC: Aftertreatment 1 Intake NOx Sensor Circuit - Voltage Above Normal.
ACTION: Check for a melted sensor wiring harness near the exhaust pipe or a loose pin connection at the 4-pin plug.
Red Seal field insights
Diagnostic Logic: High voltage usually indicates an open circuit or a signal wire shorted to a 12V/24V power supply line.
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