SCR Outlet NOx Sensor - Data Drifted High
The JD-SPN3226-FMI20 (John Deere PowerTech) diesel fault code means: SCR Outlet NOx Sensor - Data Drifted High. This is a moderate severity code.
Unverified. We could not confirm this code's definition against freely available manufacturer documentation, so treat the meaning, severity and fix guidance on this page as unconfirmed. Check it against the manufacturer's service information for your exact model and serial range before acting on it. This page is kept out of search engines for that reason, and we are working through this family manual by manual.
- Keep driving?
- Yes, with caution
- DIY difficulty
- intermediate
- Estimated cost
- $650-$1,400 sensor, $3,500-$6,500 SCR
What Are the Symptoms of JD-SPN3226-FMI20?
- Inducement timer active if not cleared
- Final rate low at SCR outlet
What Causes JD-SPN3226-FMI20? (Most Likely First)
- Outlet NOx sensor failed / contaminated Very Likely
- SCR catalyst aged Possible
Can I Still Drive with JD-SPN3226-FMI20?
Yes, with caution. JD-SPN3226-FMI20 is rated moderate severity. Keep trips short and get it diagnosed soon rather than waiting for symptoms to worsen.
Frequently Asked Questions
What is John Deere fault code SPN 3226 FMI 20?
On John Deere PowerTech engines, SPN 3226 FMI 20 means: SCR Outlet NOx Sensor - Data Drifted High. Moderate code. Keep working cautiously and plan repair.
Can I keep using my John Deere tractor with SPN 3226 FMI 20?
Moderate fault -- continue light use, fix at next service. Diagnose with John Deere Service ADVISOR via an EDL v3 / CF3 interface.
How much does it cost to fix John Deere SPN 3226 FMI 20?
Repair cost range: $650-$1,400 sensor, $3,500-$6,500 SCR. Dealer labor on large tractors runs $180-$240/hr in 2026.
Mechanics Guide Step-by-step diagnosis
How Do You Diagnose JD-SPN3226-FMI20?
Compare outlet NOx to inlet NOx; outlet should read ~10% of inlet at normal SCR temp.
Replace outlet NOx sensor first; re-test before condemning SCR.
Sources 1
This page is built from documented references. Verify against your own service info before repair work.
- SAE J1939-73Application Layer: Diagnostics (defines the SPN/FMI fault-identifier framework)
SPN3226-FMI20 on Other Platforms
The same code ID appears across other engines, vehicles, and equipment. Diagnostic flow varies by platform — see the matching breakdown:
Which Vehicles Commonly Get JD-SPN3226-FMI20?
- 2014+ John Deere 6R Series tractors
- 2015+ John Deere 7R Series tractors
- 2015+ John Deere 8R / 8RT Series tractors
- 2015+ John Deere 9R / 9RT / 9RX Series tractors
- 2015+ John Deere S670 / S680 / S690 combines
- John Deere S770 / S780 / S790 combines
- John Deere 544/644/724 wheel loaders (construction)
- John Deere 310/410 backhoes
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