SCR Conversion Efficiency - Below Normal Range
The JD-SPN4364-FMI17 (John Deere PowerTech) diesel fault code means: SCR Conversion Efficiency - Below Normal Range. This is a serious 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
- $15 DEF retest, $650-$1,400 NOx sensor, $3,500-$6,500 SCR replacement
What Are the Symptoms of JD-SPN4364-FMI17?
- DEF inducement warning -> low-idle lockout if ignored
- Failed emissions self-check
What Causes JD-SPN4364-FMI17? (Most Likely First)
- Contaminated or non-API DEF (water / wrong fluid) Very Likely
- Aged SCR catalyst (>8,000 hrs) Likely
- Leaking exhaust joint before NOx outlet sensor Possible
- Failed outlet NOx sensor Possible
Can I Still Drive with JD-SPN4364-FMI17?
Yes, with caution. JD-SPN4364-FMI17 is rated serious 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 4364 FMI 17?
On John Deere PowerTech engines, SPN 4364 FMI 17 means: SCR Conversion Efficiency - Below Normal Range. Serious code -- address promptly to avoid inducement / further damage.
Can I keep using my John Deere tractor with SPN 4364 FMI 17?
Serious fault -- you can move the machine to a shop but don't run it under load. Diagnose with John Deere Service ADVISOR via an EDL v3 / CF3 interface.
How much does it cost to fix John Deere SPN 4364 FMI 17?
Repair cost range: $15 DEF retest, $650-$1,400 NOx sensor, $3,500-$6,500 SCR replacement. Dealer labor on large tractors runs $180-$240/hr in 2026.
Mechanics Guide Step-by-step diagnosis
How Do You Diagnose JD-SPN4364-FMI17?
Test DEF with refractometer (target 32.5% urea).
Smoke-test exhaust between DOC and SCR for leaks.
Swap NOx sensors (inlet <-> outlet) and re-run.
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)
Which Vehicles Commonly Get JD-SPN4364-FMI17?
- 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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