John Deere Engines SPN3511FMI4 Fault Code: Sensor Supply #3 Voltage Out of Range Low
Also called Engine Shutdown Commanded by Application
Sensor Supply #3 Voltage Out of Range Low · ai-assisted, editor-reviewed · Last updated 2026-07-13
TL;DR
SPN 3511 FMI 4 means the ECU has detected that Sensor Supply #3, a 5-volt reference circuit, has dropped below 4.6 volts. This supply feeds sensors and actuators such as the air throttle actuator, engine oil pressure sensor, low-pressure fuel pressure sensor, EGR valve position sensor, EGR flow sensor, or exhaust throttle actuator depending on the engine configuration. It is logged as a Warning-level code and appears when the ignition is on and the fault is active.
Medium severity. This is logged as a Warning-level alarm rather than an immediate shutdown code, but because it affects sensor supply to components tied to fuel, air, and EGR control, it should be diagnosed promptly. Left unaddressed, affected sensors and actuators may not report or function correctly, which can affect engine performance and emissions control.
What does John Deere Engines error code SPN3511FMI4 mean?
SPN 3511 FMI 4 points to a low-voltage condition on Sensor Supply #3, a 5-volt reference circuit inside the ECU that powers a group of sensors and actuators. The ECU constantly monitors this supply, and when it measures voltage below 4.6 volts with the ignition on, it sets this code and logs it as a Warning.
Depending on the specific engine and configuration, Sensor Supply #3 can power the air throttle actuator, engine oil pressure sensor, low-pressure fuel pressure sensor, EGR valve position sensor, EGR flow sensor, air throttle actuator position sensor, or exhaust throttle actuator. A low voltage on this shared supply can affect one or several of these components at once, since they all draw from the same source inside the ECU.
When the fault is active, the ECU tries to maintain proper operating conditions as best it can, but accuracy and reliability of readings from the affected sensors cannot be guaranteed until the supply voltage issue is resolved.
Common causes of SPN3511FMI4
- Bad terminals or connector at the air throttle actuator, engine oil pressure sensor, low-pressure fuel pressure sensor, EGR valve position sensor, EGR flow sensor, or exhaust throttle actuator, depending on configuration
- A shorted or bad sensor or actuator on the Sensor Supply #3 circuit (air throttle actuator, engine oil pressure sensor, low-pressure fuel pressure sensor, EGR valve position sensor, EGR flow sensor, or exhaust throttle actuator)
- A short in the wiring harness on the Sensor Supply #3 circuit, including a short to a supply wire
- Too many devices connected to the Sensor Supply #3 circuit, causing the ECU to activate a current limit shutdown on that supply
- Bad terminals or connector at the ECU itself
- Bad ECU hardware
- Outdated or bad ECU software
How to troubleshoot John Deere Engines SPN3511FMI4: first checks
- Confirm the fault is active by checking with the ignition on, since this code is displayed only when the ignition is on and the error is active
- Check terminals and connectors at every component fed by Sensor Supply #3 for your engine's configuration (air throttle actuator, engine oil pressure sensor, low-pressure fuel pressure sensor, EGR valve position sensor, EGR flow sensor, or exhaust throttle actuator) for corrosion, looseness, or damage
- Inspect the wiring harness between the ECU and these components for chafed, pinched, or shorted wiring, including any short to a supply wire
- Verify that no aftermarket or additional devices have been tapped into the Sensor Supply #3 circuit, since an overloaded supply will trigger a current limit shutdown
- Check the ECU connector and terminals for corrosion or poor contact
- Confirm ECU software is up to date, since outdated or bad ECU software is listed as a possible cause
How the code clears
No separate clearing step is listed beyond correcting the underlying cause. Since the code is active only while the fault condition is present and the ignition is on, repairing the connector, harness, sensor, actuator, or ECU issue should allow the fault to clear on its own. Cycling the ignition after repair and confirming the fault does not return is good practice, though no specific reset procedure is documented.
Frequently asked questions
What does SPN 3511 FMI 4 mean on a John Deere engine?
It means the ECU has detected that Sensor Supply #3, an internal 5-volt reference circuit, has dropped below 4.6 volts. This supply powers sensors and actuators like the air throttle actuator, oil pressure sensor, fuel pressure sensor, EGR components, or exhaust throttle actuator depending on the engine.
Is SPN 3511 FMI 4 a serious problem?
It is logged as a Warning-level alarm, not an immediate shutdown code, but it should still be diagnosed soon since it can affect readings from fuel, air, and EGR-related sensors.
What components can be affected by this code?
Depending on configuration, Sensor Supply #3 feeds the air throttle actuator, engine oil pressure sensor, low-pressure fuel pressure sensor, EGR valve position sensor, EGR flow sensor, or exhaust throttle actuator.
Can too many accessories cause this fault?
Yes. If too many devices are connected to the Sensor Supply #3 circuit, the added load can cause the ECU to activate a current limit shutdown on that supply, which can set this code.
When does the fault code display?
It displays when the ignition is on and the error condition is active. It is not a stored-only code, it reflects a currently active low-voltage condition.
Will fixing a bad connector clear the code?
If a bad terminal or connector is the root cause, repairing it should stop the fault condition from recurring, but no separate reset procedure is documented, so the code should clear on its own once the ignition is cycled after the repair.
Could this be an ECU problem instead of a sensor problem?
Yes. Possible causes include bad ECU hardware, bad terminals or connector at the ECU, and outdated or bad ECU software, in addition to sensor, actuator, and harness issues.