Injector Metering Rail #2 Pressure - Current Above Normal or Grounded Circuit
The JD-SPN660-FMI6 (John Deere PowerTech) diesel fault code means: Injector Metering Rail #2 Pressure - Current Above Normal or Grounded Circuit. 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, but fix soon
- DIY difficulty
- intermediate
- Estimated cost
- $250-$950 injector or rail sensor, $1,200-$3,800 HPFP
What Are the Symptoms of JD-SPN660-FMI6?
- Low power / derate under load
- Hard start or no-start after key-off heat soak
- Fuel knock at idle, particularly on cold start
What Causes JD-SPN660-FMI6? (Most Likely First)
- Valve-cover injector harness broken at pass-through (classic PowerTech issue) Very Likely
- Sticking injector with carbon on control valve Likely
- Low rail pressure from HPFP wear or suction restriction Possible
- Water in fuel contaminating HPFP Possible
Can I Still Drive with JD-SPN660-FMI6?
Yes, but fix soon. JD-SPN660-FMI6 is rated moderate severity. It is not an immediate stop-driving fault, but it will not clear itself — book the repair rather than ignoring it.
Frequently Asked Questions
What is John Deere fault code SPN 660 FMI 6?
On John Deere PowerTech engines, SPN 660 FMI 6 means: Injector Metering Rail #2 Pressure - Current Above Normal or Grounded Circuit. Moderate code -- diagnose soon; continued operation may increase repair scope.
Can I keep using my John Deere tractor with SPN 660 FMI 6?
Moderate fault -- you can usually keep working but expect derate if aftertreatment-related. Diagnose with John Deere Service ADVISOR via an EDL v3 / CF3 interface.
How much does it cost to fix John Deere SPN 660 FMI 6?
Repair cost range: $250-$950 injector or rail sensor, $1,200-$3,800 HPFP. Dealer labor on large tractors runs $180-$240/hr in 2026.
Mechanics Guide Step-by-step diagnosis
How Do You Diagnose JD-SPN660-FMI6?
Inspect / swap cylinder injectors using Service ADVISOR cylinder-cutout test.
Measure actual vs. desired rail pressure at full load and on crank.
Drain primary water separator and recheck fuel filter service interval.
Check injector harness through the valve cover -- broken wire is a known failure.
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-SPN660-FMI6?
- 2015+ John Deere 7R Series (7210R, 7250R, 7290R, 7310R)
- 2015+ John Deere 8R / 8RT Series (8245R-8370R)
- 2015+ John Deere 9R / 9RT / 9RX Series (9370R-9620R)
- John Deere S670 / S680 / S690 combines
- John Deere S770 / S780 / S790 combines
- John Deere 544 / 624 / 724 wheel loaders
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