Detroit Diesel Fault Code
Free · no signupSPN 520372 FMI 16
Progressive 5 MPH Inducement Derate
System
Emissions
Symptom
Progressive 5 MPH Inducement Derate
Diagnosis & fix steps
LOGIC: SCR Closed Loop Control at Maximum Limit.
ACTION: Check for a crystallized or clogged DEF doser injector nozzle. Check delta pressure sensors and run an active parked regeneration, immediately followed by an SCR Efficiency Test.
Red Seal field insights
Inducement Risk: If ignored, this code cascades into active inducement lockouts (SPN 521049 / SPN 521052). It indicates the system is using excessive DEF to maintain compliance due to a failing catalyst brick or bad upstream readings.
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