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Cummins Engines · 3725
Aftertreatment 1 Intake NOx Sensor Fault
What this code means
Aftertreatment 1 Intake NOx Sensor - Data Erratic, Intermittent, or Incorrect (abnormal update / rationality)
Applies to: all electronic engines.
Possible causes / checks (from the source)
SPN 3216, FMI 10
Need the part?
If diagnosis points to a failed sensor, solenoid, controller or harness part, send us the code (3725), machine model and serial number — we quote genuine and OEM replacement parts for export.
Ask for the replacement part on WhatsAppSource: 30-Minute DPF Clean — Cummins fault code list. Single published source — confirm against the manual for your exact model before ordering parts. Compiled 2026-10-30. No manufacturer affiliation.