SPN 3226: Outlet NOx Codes by Engine
What SPN 3226 identifies
SPN 3226 identifies outlet NOx in the aftertreatment system. DEF tank level is 1761; inlet NOx is 3216. Record the FMI and reporting controller before selecting a test. A sensor-related code does not, by itself, establish that the sensor needs replacement.
Documented SPN/FMI examples
Scroll horizontally to see the application and source.
| SPN / FMI | OEM FC | Meaning | Application / source |
|---|---|---|---|
3226 / 2 | 1694 | Erratic NOx data | Cummins 2013 ISX15/ISX12/ISL9/ISB6.7* Cummins SPN/FMI cross-reference — Atlas Copco |
3226 / 4 | 1887 | Low circuit voltage | Cummins 2013 ISX15/ISX12/ISL9/ISB6.7* Cummins SPN/FMI cross-reference — Atlas Copco |
3226 / 9 | 2771 | Irregular/missing updates | Cummins 2013 ISX15/ISX12/ISL9/ISB6.7* Cummins SPN/FMI cross-reference — Atlas Copco |
3226 / 20 | 3749 | High drift | Cummins 2013 ISX15/ISX12/ISL9/ISB6.7* Cummins SPN/FMI cross-reference — Atlas Copco |
3226 / 2 | — | Outlet NOx drift | Detroit DD EPA10/GHG14 Detroit 01 15-17 (January 2017) |
3226 / 10 | — | Abnormal rate of change | Navistar N13 before 2014-08-01; N9/10 before 2015-08-01, specified vertical exhaust* Navistar IK0700087 (November 2015) |
Examples only; a dash means no separate FC is supplied here. *See source applicability below; a model name alone does not establish calibration coverage.
The Detroit example is specifically EPA10/GHG14 DD heavy-duty FMI 2. The Navistar water-shield bulletin also covers FMI 4 and is limited to listed vertical-exhaust configurations and build dates. Neither procedure applies automatically to every truck with 3226. Detroit 01 15-17 (January 2017) · Navistar IK0700087 (November 2015)
Choose the diagnostic branch
- Record engine serial, emissions generation, active and inactive codes, occurrence counts, and available freeze-frame data. Confirm the matching OEM procedure.
- For a circuit or update-rate code, establish sensor power, ground and communication using that engine's wiring diagram before interpreting NOx performance.
- For the cited Detroit FMI 2 procedure, investigate exhaust condition and DEF dosing before deciding whether the sensor is responsible. Its 108–132 mL quantity criterion belongs to the specified service routine; it is not a universal dosing specification.
- Use the manufacturer's verification routine after repair. A cleared code alone does not demonstrate a successful repair.
Sources and applicability
Source check: September 12, 2026. These are documented examples. Confirm the engine serial number, software calibration and current OEM instructions before using a test or repair procedure.
- Cummins SPN/FMI cross-reference — Atlas Copco — 2013 ISX15, ISX12, ISL9 and ISB6.7; use only the applications marked in the source table.
- Detroit 01 15-17 (January 2017) — EPA10/GHG14 DD heavy-duty, SPN 3226/FMI 2; DDC-SVC-MAN-0084.
- Navistar IK0700087 (November 2015) — SCR with specified vertical exhaust: N13 built before August 1, 2014; N9/10 before August 1, 2015. Confirm exhaust feature code.
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