The Cummins ISX code 3725 manual is a 7-page PDF that documents fault code 3725, the aftertreatment intake NOx sensor abnormal rate of change fault. It explains that the aftertreatment intake NOx smart sensor reports over the J1939 data link, and that this code is set when the sensor reading is judged not valid while exhaust temperature is above 150 C (302 F). The procedure is credited to TruckFaultCodes.com and covers the circuit description, component location and full troubleshooting steps.
Official document details
| Brand | Cummins |
| Model coverage | Cummins ISX11.9 CM2250 and ISX12 CM2250 (2010-12) engines |
| System / group | ISX11.9 CM2250 (2010-12) / DTCs |
| Fault code | 3725 (PID P102, SPN 3216, FMI 10) |
| Warning lamp | Amber |
| Pages | 7 |
| File size | 0.2 MB |
| Format | |
| Language | English |
Document table of contents
- Fault code 3725 description
- Circuit description and ECM operation
- Component location
- Shop talk and possible causes
- Step-by-step troubleshooting flow
Applicable truck models
This diagnostic applies to Cummins ISX11.9 CM2250 and ISX12 CM2250 (2010-12) engines. The aftertreatment intake NOx sensor is mounted near the turbocharger turbine outlet and is serviced only with its NOx control module. The reported cause is an invalid intake NOx sensor reading, with no direct effect on performance. For engine data and authorised service, visit the Cummins official website.
Who needs this Cummins ISX code 3725 manual
Heavy-duty diesel technicians, fleet workshops and owner-operators reach for this manual when fault code 3725 is logged and the amber warning lamp is on. It helps an emissions technician confirm an unstable NOx signal and decide whether the sensor assembly must be replaced.
Download the ISX code 3725 PDF
The complete procedure, wiring detail and step tables are available in the DiagTechPro manuals library; a free account is required to download the PDF. Keep it alongside the related ISX11.9 CM2250 fault-code sheets listed below.
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