This page covers the Detroit fault code SPN 5017 FMI 4, NOx Sensor Digital Output 5 Circuit Signal Failed Low, on DD Platform engines. It documents the SCR outlet NOx sensor and ACM harness diagnostic flow.
Official document details
| Brand | Detroit |
| Model coverage | Detroit DD13, DD15 and DD16 (DD Platform) |
| System / Group | DD Series (EPA 2007-Current) / DTCs |
| Source | TruckFaultCodes.com |
| Year / Revision | 2017 (EPA10 / GHG14) |
| Pages | 2 |
| File size | 0.30 MB |
| Format | |
| Language | English |
SPN 5017 FMI 4 table of contents
- Fault description and affected circuit
- SCR outlet NOx sensor connector check
- Supply voltage measurement to ACM
- Sensor resistance and harness tests
- ACM internal resistor test
This circuit fault targets the SCR outlet NOx sensor and its wiring to the Aftertreatment Control Module (ACM). The procedure begins by disconnecting the sensor and inspecting the harness for bent, spread or corroded pins.
With the key on, supply voltage between pins 1 and 4 is measured (should be under 11.5 volts) and the wire is traced to ACM pins 42 or 43. With the key off, resistance between pins 2 and 3 is checked against 50-70 ohms; out-of-range values lead through short and open tests to ACM pins 40 and 41. If the ACM internal resistor reads 50-70 ohms, the SCR outlet NOx sensor is replaced; otherwise the ACM is replaced.
Applicable truck models
This guide applies to Detroit DD13, DD15 and DD16 engines on EPA10 and GHG14 aftertreatment. Sensor removal follows the EPA10 SCR Outlet NOx Sensor procedure in Power Service Literature, referencing the ACM 120-pin connector. Manufacturer resources are at Detroit’s official website.
Who needs this SPN 5017 FMI 4 manual
Electrical and aftertreatment technicians diagnosing a low NOx sensor signal on DD Series trucks use this document to verify wiring and the ACM before replacing the sensor.
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