John Deere Engines SPN652FMI5 Fault Code: Injector #2 Circuit Has High Resistance
Also called Cylinder #2 EI Circuit Open, Cylinder #2 EUI Circuit Open, Cylinder #2 EUI Cirucit Open, Electronic Unit Pump #2 Circuit Has High Resistance, Injector #2 Spill Valve Circuit Has High Resistance, Injector #3 Circuit Has High Resistance
Injector #2 Circuit Has High Resistance · ai-assisted, editor-reviewed · Last updated 2026-07-13
TL;DR
SPN 652 FMI 5 means the ECU has detected an open circuit or high resistance in the cylinder #2 injector circuit, whether that is an electronic unit injector (EUI), electronic injector (EI), or common-rail electronic injector depending on engine family. When this code sets, cylinder #2 will not fire and the ECU flags it as a Warning while continuing to control the engine in a normal manner.
Medium severity. This is logged as a Warning-level alarm and the ECU keeps controlling the engine normally, but a dead or misfiring cylinder #2 will cause rough running, power loss, and possible long-term wear if ignored. Diagnose within the shift rather than running it indefinitely.
What does John Deere Engines error code SPN652FMI5 mean?
John Deere engines covered by this code use one of a few fuel delivery designs depending on displacement. On 10.5 L and 12.5 L engines, fuel is delivered by six electronic unit injectors (EUIs), each combining an injection pump and injector, mounted in the cylinder head and firing directly into the cylinder bore. On 8.1 L engines, six electronic injectors (EIs) receive fuel from a high pressure common rail. Other engine families use a similar electronic injector circuit with a shared high voltage supply and individual ground control per cylinder.
In every version, the ECU controls injection timing and fuel quantity by switching a solenoid or valve inside the injector housing on and off. Power to injectors is usually supplied in groups (cylinders 1, 2, 3 on one common wire, and 4, 5, 6 on another), while the ECU switches the low side, or ground, of each individual injector circuit to fire it.
SPN 652 FMI 5 specifically means the ECU has detected an open circuit, or in some versions a high resistance condition of a few extra ohms, somewhere in the cylinder #2 injector circuit. This can be in the wiring, connectors, the injector itself, or the ECU. When it sets, cylinder #2 will not fire, which shows up as a rough-running or misfiring engine.
What triggers a John Deere Engines SPN652FMI5 code?
On engines using the high-resistance version of this fault, the code can be displayed while the engine is cranking or running with the error condition active, or during a Harness Diagnostic Mode Test in Service ADVISOR provided fuel rail pressure is below 5 MPa (725 psi). On the EUI and EI versions, the code sets when the ECU simply detects an open in the cylinder #2 injector circuit, with no separate pressure or time threshold given.
Common causes of SPN652FMI5
- Bad terminals or connector at the ECU
- Bad terminals or connector at the EUI, EI, or injector harness connector, including the 12-way (6.8L) or 6-way (4.5L) connector on some engines
- Bad #2 injector, EUI, or EI solenoid/valve itself
- Bad injector wiring harness, including the harness inside the cylinder head on EUI engines
- Open or short in the harness between the ECU and the injector or EUI/EI harness connector, or in the main harness
- Open or short in the 90V circuit on EI-equipped engines
- Bad ECU or bad ECU software
- An open circuit in the shared injector high voltage supply, which can also trigger high-resistance DTCs on other injector circuits at the same time
How to troubleshoot John Deere Engines SPN652FMI5: first checks
- Visually inspect the ECU connector(s), the EUI/EI or injector harness connector (located at the back or side of the cylinder head depending on engine), and any connectors in between for dirt, corrosion, damage, or terminals that are pushed back or poorly seated
- Check the wiring harness for chafing, pinches, or damage between the ECU and the injector connector, paying attention to the shared power wire feeding cylinders 1, 2, and 3
- If other injector circuits are also showing high-resistance codes at the same time, suspect an open in the shared high voltage supply feeding all injectors rather than a single injector problem
- Check for related active codes, especially SPN 627 FMI 1, since John Deere lists that code in the same troubleshooting sequence as SPN 652 FMI 5 on the high-resistance version of this fault
- With the engine off, check resistance and continuity through the #2 injector circuit from the ECU connector to the injector, looking for the few extra ohms of resistance or the open circuit described in the fault
How the code clears
No separate clearing step or reset procedure is listed for this code. Once the open circuit or high resistance condition in the cylinder #2 injector circuit is repaired, the code should stop being active on the next key cycle or engine run. If using Service ADVISOR's Harness Diagnostic Mode Test, keep in mind the test is only valid when fuel rail pressure is below 5 MPa (725 psi).
Frequently asked questions
What does SPN 652 FMI 5 mean on a John Deere engine?
It means the ECU has detected an open circuit or high resistance in the cylinder #2 injector circuit. Depending on the engine, this circuit may serve an electronic unit injector (EUI), an electronic injector (EI), or a common-rail style electronic injector. The result is that cylinder #2 will not fire correctly.
Can I keep driving or running the engine with this code active?
The ECU logs this as a Warning-level alarm and will attempt to control the engine in a normal manner, but cylinder #2 not firing means rough running and lost power. It is best treated as a diagnose-soon issue rather than an emergency shutdown, but should not be ignored long-term.
Where should I check first for this fault?
Start with a visual inspection of the ECU connector, the injector or EUI/EI harness connector at the cylinder head, and everything in between. Look for dirty, damaged, or poorly seated terminals before moving to wiring continuity and resistance checks.
Is SPN 652 FMI 5 related to any other codes?
On the high-resistance version of this fault, John Deere lists a troubleshooting sequence that includes SPN 627 FMI 1 alongside SPN 652 FMI 5. If both are active, the injector high voltage supply circuit is a likely shared cause.
Does this code mean the injector itself is bad?
Not necessarily. Possible causes listed include a bad injector or EUI/EI, but also bad terminals or connectors, an open or short in the harness, or even a bad ECU or ECU software. A full circuit check is needed before condemning the injector.
Will this code clear itself after I fix the wiring?
No separate clearing or reset procedure is documented for this code. Once the open or high resistance condition is repaired, the fault should stop setting on its own during normal engine operation or diagnostic testing.