SPN 3226 FMI 3 is the Detroit DD Series fault-code procedure for an SCR outlet NOx sensor circuit failed-high fault. This 1-page diagnostic PDF documents the fault, its monitored circuit on the SCR outlet NOx sensor, and the exact troubleshooting steps a technician follows to confirm and repair the failure.
Official document details
| Brand | Detroit |
| Model coverage | DD Series (EPA 2007-Current); Series 60 DDEC VI |
| System / Group | DD Series / DTCs |
| SPN (fault code) | 3226 |
| FMI (failure mode) | 3 |
| Emission family | EPA10 / GHG14 calibration |
| Source | Detroit Power Service Literature (Copyright © 2017) |
| Pages | 1 |
| File size | 0.26 MB |
| Format | |
| Language | English |
Document table of contents
- Fault code identification (SPN 3226, failure mode 3)
- Fault description and enabling conditions
- Troubleshooting steps
- DTC occurrence counter check
Applicable truck models
This procedure applies to Detroit DD13, DD15 and DD16 engines in the DD Series (EPA 2007-Current) range and the equivalent Series 60 (DDEC VI) platform, as fitted to Freightliner and Western Star trucks. Confirm the EPA10 / GHG14 emission family matches the truck before following the steps; full model and coverage data is published on the Detroit official website.
Who needs this SPN 3226 FMI 3 manual
Diesel technicians, fleet workshops and mobile mechanics diagnosing an SCR outlet NOx sensor circuit reading failed high on EPA10 or GHG14 Detroit engines need this reference to test the circuit correctly with a diesel diagnostic tool instead of replacing parts by guesswork.
SPN 3226 FMI 3 repair steps explained
This is a short, counter-based procedure. The technician checks the DTC occurrence counter for this circuit-failed-high code: if the counter is 5 or less the fault is cleared and the vehicle released, and if it is higher the SCR outlet NOx sensor is replaced per Detroit Power Service Literature. The monitor is always enabled with a typical two-second duration and lights the MIL and CEL dash lamps, and it is verified by a one-minute engine idle using a diesel diagnostic tool.
The full PDF is available in the DiagTechPro manuals library; a free account is required to download it.
Related manuals library
