John Deere Engines SPN1075FMI6 Fault Code: Low-Pressure Fuel Pump Circuit Has Low Resistance
Also called Low Pressure Fuel Pump Circuit Has Low Resistance
Low-Pressure Fuel Pump Circuit Has Low Resistance · ai-assisted, editor-reviewed · Last updated 2026-07-13
TL;DR
SPN 1075 FMI 6 means the ECU has detected low resistance (an apparent short toward ground or excess current) in the low-pressure fuel pump power or control circuit. It sets as a Warning-level code when the ignition is on, the fuel pump is commanded on, and the fault is active for longer than 60 seconds.
Medium severity. This is logged as a Warning alarm level, and the ECU tries to keep operating in a normal manner. It is not an immediate shutdown code, but a fuel delivery problem left unaddressed can lead to hard starting, low power, or a stranded machine, so it should be diagnosed the same shift it appears.
What does John Deere Engines error code SPN1075FMI6 mean?
SPN 1075 FMI 6 points to the low-pressure fuel pump, sometimes called the transfer pump, and its power or control circuit. This pump moves fuel from the tank through the filter header to the high-pressure system. On these engines the pump reports its current draw to the ECU over CAN, and the ECU compares that reported value against an internal threshold. When the reported current is higher than expected, or the ECU sees low resistance (which can look like a short to ground) in the relay control circuit, it logs this fault.
In plain terms, the ECU is watching the electrical health of the fuel pump circuit. Low resistance usually means current is finding an unintended path, whether through worn wire insulation, a shorted pump winding, a bad relay, or a failed valve inside the fuel filter header assembly.
The ECU responds by trying to keep the engine running as close to normal as possible, but a fuel pump circuit problem can still cause rough running, hard starting, or a no-start if it worsens.
What triggers a John Deere Engines SPN1075FMI6 code?
The DTC sets when the ignition is on, the low-pressure fuel pump (or its relay) is commanded on by the ECU, and the low-resistance error condition stays active for longer than 60 seconds. The ECU only checks for low resistance in the pump or relay control circuit while that output is switched on. If the ignition stays on for 60 seconds without the engine running, the ECU switches the fuel pump output off, which also affects when the check can occur.
Common causes of SPN1075FMI6
- Bad or corroded terminals or connector at the low-pressure fuel pump connector
- Bad or corroded terminals or connector at the ECU
- Bad terminals or connector at the low-pressure fuel pump relay connector
- Open or short in the wiring harness between the low-pressure fuel pump and the ECU
- Bad low-pressure fuel pump air bleed fitting
- Bad low-pressure fuel pump itself
- Bad low-pressure fuel pump relay
- Bad fuel filter header assembly, including a failed recirculation valve inside it
- Restricted fuel return line or insufficient flow out of the leak-off line
- High resistance in the fuel return or supply circuit
- Bad ECU software
- Bad ECU
How to troubleshoot John Deere Engines SPN1075FMI6: first checks
- Inspect the low-pressure fuel pump connector and terminals for corrosion, looseness, or pushed-back pins
- Inspect the ECU connector and terminals for the same kind of damage
- Inspect the low-pressure fuel pump relay and its connector if the machine uses a relay-controlled circuit
- Visually trace the wiring harness between the fuel pump (or relay) and the ECU, looking for chafed, pinched, or shorted wire insulation
- Check the low-pressure fuel pump air bleed fitting for damage or a bad seal
- Check the fuel filter header assembly, including the recirculation valve, for a failure that could feed back into the pump circuit
- Check the fuel return line and leak-off line for restrictions that could load the pump abnormally
- Confirm ECU software level is correct if all wiring and components check out
How the code clears
No separate clearing step is listed. Once the underlying wiring, connector, pump, relay, or fuel filter header issue is repaired, the code should stop being active on the next key cycle when the ECU rechecks the circuit while the fuel pump output is commanded on. If the fault will not clear after a confirmed repair, ECU software or the ECU itself should be checked, since bad ECU software or a bad ECU are both listed as possible causes.
Frequently asked questions
What does SPN 1075 FMI 6 mean on a John Deere engine?
It means the ECU detected low resistance, essentially an unexpected short-to-ground type condition, in the low-pressure fuel pump's power or control circuit. It is logged as a Warning after the fault stays active for more than 60 seconds while the ignition is on and the pump is commanded on.
Can I keep running the machine with this code active?
The alarm level is Warning, and the ECU tries to keep operating normally, so the engine may keep running. However, since this affects fuel delivery hardware, it should be diagnosed promptly rather than ignored, since pump or relay failure can progress to a no-start or power loss.
Is this the same as SPN 1075 FMI 4?
No. FMI 4 and FMI 6 are separate fault codes for the same circuit, and John Deere lists both in the same troubleshooting sequence along with SPN 94 FMI 16 and SPN 94 FMI 17. Each FMI represents a different type of detected electrical fault, so they should be diagnosed as distinct codes even though they involve related wiring.
What parts commonly cause this fault?
The most commonly cited causes are corroded or damaged connectors at the pump, relay, or ECU, an open or shorted harness section, a bad low-pressure fuel pump or relay, a bad fuel filter header assembly (including its recirculation valve), and in some cases restricted return or leak-off flow.
Does a bad fuel filter really trigger an electrical fault code?
Yes, indirectly. The fuel filter header assembly on these engines houses a recirculation valve. If that valve fails, it can affect the fuel pump's load and current draw enough that the ECU interprets it as a low-resistance circuit problem, even though the root cause is mechanical.
Why does the ECU only check this circuit sometimes?
The ECU only monitors for low resistance while the low-pressure fuel pump or relay output is actively switched on. If the ignition is on but the engine has not started within 60 seconds, the ECU turns that output off, which pauses the check until the output is commanded on again.
Will a wiring repair alone fix this code?
It depends on the root cause. If the issue is a chafed or shorted wire, a wiring repair should resolve it. But if the true cause is a failing pump, relay, or fuel filter header assembly, the code will likely return even after a harness repair, so all listed causes should be checked before closing out the repair.