Aftertreatment outlet NOx sensor voltage low – poor NOx data
Aftertreatment outlet NOx sensor voltage low – poor NOx data
This appears when the SCR outlet NOx sensor reports voltage lower than expected. It often shows with mild aftertreatment warnings before a bigger issue. Common failure points are the wiring harness near the sensor head, where moisture gets in.
The videos below are embedded using YouTube’s official player. We do not host or claim ownership of this content. Use it as a visual reference and always confirm with diagnostics for your exact truck configuration.
Compare symptoms, repairs and real-world experience from drivers, technicians and owner-operators.
Ask the community and include your truck year, make, engine, active codes, symptoms and recent repairs so people can give useful answers instead of performing mechanical astrology.
Ask the Community →
Mechanic community notes for SPN 3226 FMI 4
Back to top ↑Real-world tips from technicians. Submissions are moderated to keep spam and “my cousin fixed it with duct tape” content out.
Share your fix / advice
Keep it useful: symptoms, what you checked, what fixed it, and whether the code stayed inactive after a drive cycle.