John Deere Engines SPN655FMI7 Fault Code: Injector #5 Not Responding
Also called Cylinder #5 EI Fuel Delivery Failure, Cylinder #5 EI Mechanical Failure
Injector #5 Not Responding · ai-assisted, editor-reviewed · Last updated 2026-07-13
TL;DR
SPN 655 FMI 7 means the ECU did not see the fuel rail pressure drop that should happen when electronic injector #5 fires. The engine will miss or run rough at cylinder #5 because that injector is not injecting fuel as commanded. This is logged as a Warning-level code on affected John Deere engines.
Medium severity. The engine keeps running but will misfire and run rough at cylinder #5. It is not an immediate shutdown condition, but ignoring it risks injector damage, uneven cylinder loading, and rising fuel or emissions problems, so it should be diagnosed before continued heavy use.
What does John Deere Engines error code SPN655FMI7 mean?
SPN 655 FMI 7 points at cylinder #5's electronic injector (EI) on John Deere engines that use a high pressure common rail fuel system. Each EI sits in the cylinder head under the valve cover and sprays fuel directly into the cylinder. The ECU controls each injector's Two-Way Valve (TWV) by opening and closing that injector's ground circuit, which opens and closes the EI spill valve to start and meter injection.
This code sets specifically because the ECU expects to see fuel rail pressure drop each time cylinder #5's injector fires, and that pressure drop did not happen. In other words, the ECU commanded the injection but got no confirming signal that fuel actually left the rail toward cylinder #5.
Power to groups of injectors is shared on a common wire (for example, cylinders 1-2-3 on one wire and 4-5-6 on another on 6-cylinder engines), while each injector has its own ground circuit that the ECU switches individually. Because of this wiring layout, a fault can trace back to a shared power circuit, a cylinder-specific ground or connector, the injector itself, the fuel line feeding it, or the ECU.
Common causes of SPN655FMI7
- Bad terminals or connector at the ECU
- Bad terminals or connector at the EI (injector) harness connector
- Restricted, leaking, pinched, bent, or cracked fuel line between the high pressure common rail and the inlet to the #5 injector
- Bad flow limiter on the #5 injector fuel line
- Bad fuel line fitting or bad fuel inlet connector at the #5 injector
- Loose retaining nuts at the #5 injector
- Bad #5 injector, including dirty injectors or a fuel leak-off test failure
- Incorrect high pressure pump timing
- Failed cylinder cutout test or failed cylinder misfire test
- Bad ECU software
- Bad ECU
How to troubleshoot John Deere Engines SPN655FMI7: first checks
- With the ignition off, visually inspect the ECU connectors and the injector harness connector at the side of the cylinder head for contamination, damage, or a connector that is not fully seated
- Check the wiring harness between the ECU and the #5 injector for chafing, pinches, or damage, paying attention to the shared power wire and the individual ground circuit for that injector
- Inspect the fuel line from the high pressure common rail to the #5 injector for leaks, restrictions, pinches, bends, or cracks, and check that the fuel line fitting and fuel inlet connector at the injector are tight and undamaged
- Check that the retaining nuts holding the #5 injector in the cylinder head are torqued and not loose
- Look for dirty injectors or contamination in the fuel supply that could affect injector #5 specifically
- Confirm whether the fault is active only when the ignition is on and stays active, since that is when this code is displayed
How the code clears
No separate clearing step is listed. The code is described as active whenever the ignition is on and the fault condition is present, so once the underlying wiring, fuel line, injector, or ECU issue is repaired, the code should stop being active on its own. Run the engine and confirm the misfire at cylinder #5 is gone and recheck for the code before returning the machine to service.
Frequently asked questions
What does SPN 655 FMI 7 mean on a John Deere engine?
It means the ECU did not detect the expected drop in fuel rail pressure when it commanded electronic injector #5 to fire. The ECU treats this as a fuel delivery failure at that specific cylinder.
Can I keep running the engine with this code active?
The engine will keep running, but it will miss or run rough at cylinder #5 because that injector is not delivering fuel correctly. Continued operation risks uneven cylinder loading and further injector or fuel system damage, so it should be diagnosed promptly.
Is this a wiring problem or an injector problem?
It can be either, or a fuel line problem, or an ECU problem. Causes listed include bad connectors at the ECU or injector harness, damaged or restricted fuel lines to the #5 injector, a bad flow limiter, loose retaining nuts, a bad #5 injector, incorrect high pressure pump timing, bad ECU software, or a bad ECU itself.
Where is the #5 injector connector located?
The injector harness connector is located at the side of the cylinder head. The injectors themselves are mounted in the cylinder head under the valve cover, spraying directly into the center of the cylinder bore.
Does this code affect other cylinders too?
Injectors share power on common wires in groups, such as cylinders 1, 2, and 3 on one wire and 4, 5, and 6 on another, but each injector has its own ground circuit. A wiring fault on a shared power circuit could potentially affect more than one cylinder, but this specific code is tied to a failed pressure drop detection at cylinder #5 alone.
What alarm level does this code trigger?
It is logged as a Warning level alarm. The engine keeps running but will run rough and misfire at cylinder #5 while the fault is active.
Does the code clear itself once the injector or wiring is fixed?
No separate clearing procedure is listed. The fault is described as active whenever the ignition is on and the underlying condition is present, so repairing the cause should stop the code from being active, and you should verify this by rechecking after the repair.