Cummins Fault Code
Free · no signupSPN: 3582 FMI: 2
SCR System Fault / Derate.
System
Aftertreatment
Symptom
SCR System Fault / Derate.
Diagnosis & fix steps
LOGIC: SCR Catalyst Intake Temperature - Data Erratic.
ACTION: Inspect the SCR temperature sensor harness for rubbing. Swap sensor with the SCR Outlet sensor to see if the fault follows.
Red Seal field insights
Specs: Voltage should fluctuate between 0.5V and 4.5V.
RED SEAL FIX: This is often a "correlation" error. If the sensors differ by more than 25°C at dead-cold (engine off 8+ hours), the ECM flags an FMI 2.
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