John Deere Engines SPN654FMI5 Fault Code: Injector #4 Circuit Has High Resistance
Also called Cylinder #4 EI Circuit Open, Cylinder #4 EUI Circuit Open, Electronic Unit Pump #4 Circuit Has High Resistance, Injector #1 Circuit Has High Resistance, Injector #4 Spill Valve Circuit Has High Resistance
Injector #4 Circuit Has High Resistance · ai-assisted, editor-reviewed · Last updated 2026-07-13
TL;DR
SPN 654 FMI 5 means the John Deere ECU has detected an open circuit or high resistance in the cylinder #4 injector circuit, whether that engine uses electronic unit injectors (EUI), electronic injectors (EI) with a two-way valve, or a common rail injector setup. When it sets, cylinder #4 will not fire, so expect a rough-running or misfiring engine while the fault is active.
Medium severity. The engine keeps running and the ECU tries to control it normally, but with cylinder #4 not firing you get lost power, rough idle, and increased wear from unbalanced combustion. Diagnose it within the shift rather than ignoring it, since prolonged single-cylinder misfire can affect emissions components and fuel system components over time.
What does John Deere Engines error code SPN654FMI5 mean?
SPN 654 FMI 5 points to an electrical problem in the wiring or connections that fire the #4 injector, not a fuel quality or mechanical timing problem. On 10.5 L and 12.5 L engines this circuit feeds the #4 electronic unit injector (EUI), a combined pump and injector mounted in the cylinder head that the ECU fires by opening and closing a ground circuit to its solenoid. On 8.1 L engines it is the #4 electronic injector (EI), which uses a two-way valve (TWV) fed by the high-pressure common rail instead of an internal pump.
In all these designs, injectors for cylinders 1, 2, and 3 share one power wire, and injectors for cylinders 4, 5, and 6 share another. The ECU controls each individual injector by switching its ground side on and off. When the ECU sees an open circuit, or in the common-rail injector variant, just a few extra ohms of resistance anywhere in the #4 injector circuit, it sets this code.
The immediate effect is that cylinder #4 does not fire at all. On common-rail systems, the alarm level is listed as a Warning, and the ECU keeps trying to run the engine normally rather than shutting it down or entering a hard limp mode.
What triggers a John Deere Engines SPN654FMI5 code?
The ECU sets this code when it detects an open circuit, or on common-rail injector systems, high resistance (even just a few ohms of extra series resistance) anywhere in the cylinder #4 injector circuit. On common-rail systems this DTC is active while the engine is cranking or running, and it can also be displayed during the Harness Diagnostic Mode Test in Service ADVISOR, provided fuel rail pressure is below 5 MPa (725 psi) at the time of the test.
Common causes of SPN654FMI5
- Bad terminals or connector at the ECU (48-way connector on EUI engines)
- Bad terminals or connector at the injector harness connector (EUI, EI, or common-rail injector connector at or near the cylinder head)
- Open or short in the wiring harness between the ECU and the injector connector, including the main harness or the 90V circuit on EI engines
- Bad #4 injector itself (EUI, EI solenoid/TWV, or common-rail injector)
- Bad injector harness inside the cylinder head or along the engine
- Bad ECU, including a bad ECU connector connection or, on some systems, bad ECU software
- An open circuit in the shared injector high-voltage supply, which can also trigger high-resistance codes on other injector circuits at the same time
How to troubleshoot John Deere Engines SPN654FMI5: first checks
- Visually inspect the ECU connector (the 48-way connector on EUI-equipped engines) for dirty, damaged, bent, or poorly seated terminals
- Inspect the injector harness connector at the cylinder head (located at the back of the head on EUI engines, at the side of the head on EI engines) for contamination, damage, or poor positioning
- Check all wiring and connectors in between the ECU and the injector for chafing, corrosion, pinched wires, or loose pins
- On common-rail-injector engines, note that this code shares a troubleshooting sequence with SPN 627 FMI 1, so check that code and the shared high-voltage supply circuit as well, since an open in that supply can trigger high-resistance codes on multiple injectors at once
- Confirm fuel rail pressure is below 5 MPa (725 psi) before relying on results from the Harness Diagnostic Mode Test in Service ADVISOR on common-rail systems
- If connectors and wiring check out, test the #4 injector itself and the injector harness for continuity and resistance before condemning the ECU
How the code clears
No separate clearing step or reset procedure is listed for this code. Once the underlying open circuit or high-resistance connection is repaired, the code should stop being active; verify by cranking or running the engine and confirming cylinder #4 fires normally and the fault does not reset.
Frequently asked questions
What does John Deere SPN 654 FMI 5 mean?
It means the ECU has detected an open circuit or high resistance in the wiring that fires the cylinder #4 injector, whether that is an electronic unit injector, an electronic injector with a two-way valve, or a common-rail injector. Cylinder #4 will not fire while the code is active.
Can I keep driving or working with SPN 654 FMI 5 active?
On systems where the alarm level is listed as a Warning, the ECU keeps trying to control the engine in a normal manner, so the machine will typically keep running. Expect rough running, lost power, and possibly rougher idle from the dead cylinder, and get it diagnosed within the shift rather than running it long term.
Where should I check first for this code?
Start with the ECU connector and the injector harness connector at the cylinder head. Look for dirty, damaged, or poorly seated terminals, then work along the harness between the two, checking for chafing, corrosion, or damage.
Is SPN 654 FMI 5 related to any other fault codes?
On common-rail injector engines, John Deere lists a troubleshooting sequence that pairs this code with SPN 627 FMI 1, since both relate to the shared injector high-voltage supply. An open in that shared supply circuit can cause high-resistance codes on multiple injector circuits at the same time.
Does this code mean the injector itself is bad?
Not necessarily. Causes range from bad terminals or connectors at the ECU or injector harness, to an open or short in the harness in between, to a bad injector, bad injector harness, or even a bad ECU. Visual and continuity checks of the wiring should be done before replacing the injector.
Will a bad ECU cause this code?
Yes, a bad ECU or a bad connection at the ECU connector is listed as a possible cause on every version of this code, including bad ECU software on some common-rail systems. It is usually checked last, after wiring and injector connections are confirmed good.