John Deere Engines SPN3510FMI4 Fault Code: Sensor Supply #2 Voltage Out of Range Low
Also called Engine Shutdown Commanded by Application
Sensor Supply #2 Voltage Out of Range Low · ai-assisted, editor-reviewed · Last updated 2026-07-13
TL;DR
SPN 3510 FMI 4 means the ECU has detected the Sensor Supply #2 5-volt circuit reading below 4.59 volts (some versions list 4.6 volts) while the ignition is on. This supply feeds several sensors depending on the engine configuration, including oil pressure, intake manifold air pressure, low pressure fuel pressure, VGT vane position, fuel dosing pressure sensors, secondary analog throttle, and droop/ISOC governor switch. The alarm level is Warning, and the ECU will try to maintain the engine operating envelope, but performance may be affected.
Medium severity. This is logged as a Warning level code. The ECU attempts to keep running and maintain the operating envelope, but engine performance may be reduced since key sensors sharing this supply can lose accurate readings. It should be diagnosed promptly rather than ignored, since continued operation with a degraded sensor supply can mask other problems.
What does John Deere Engines error code SPN3510FMI4 mean?
This code applies to a shared 5-volt reference supply inside the ECU called Sensor Supply #2. Several sensors on the engine use this common voltage as their power reference, so when the ECU sees the supply drop below spec, it cannot trust the readings coming back from any sensor tied to that circuit.
Depending on the specific engine and ECU connector configuration, the sensors fed by Sensor Supply #2 can include the engine oil pressure sensor, intake manifold air pressure sensor, low pressure fuel pressure sensor (optional), VGT vane position sensor, fuel dosing inlet and outlet pressure sensors, secondary analog throttle, and the droop/ISOC governor switch. The exact list depends on which ECU connector faces (J1 black, J2 brown or red, J3 blue) are populated on that particular engine.
Because this is a shared supply, one bad sensor or a short anywhere on the circuit can drag the whole 5-volt rail down and affect every sensor riding on it. The ECU responds by trying to maintain the operating envelope and keep the engine running, but you should expect reduced performance or erratic readings until the fault is fixed.
What triggers a John Deere Engines SPN3510FMI4 code?
The ECU sets this code whenever the ignition is on and it detects the Sensor Supply #2 circuit voltage below 4.59 volts (one variant states below 4.6 volts). The fault is active any time these conditions are met during key-on operation.
Common causes of SPN3510FMI4
- Bad or corroded terminals/connector at the engine oil pressure sensor, intake manifold air pressure sensor, low pressure fuel pressure sensor, VGT vane position sensor, fuel dosing inlet/outlet pressure sensor, secondary analog throttle, or droop/ISOC governor switch, depending on which sensors are wired to Sensor Supply #2 on that engine
- A shorted sensor on the Sensor Supply #2 circuit, such as the oil pressure sensor, manifold air pressure sensor, low pressure fuel sensor, secondary analog throttle, or VGT vane position sensor
- A short or open circuit in the wiring harness between the ECU and the affected sensors
- Too many devices connected to the Sensor Supply #2 circuit, causing the ECU to hit a current limit and shut the supply down
- A bad ECU connector or corroded terminals at the ECU itself
- A faulty ECU
- Bad or corrupted ECU software
How to troubleshoot John Deere Engines SPN3510FMI4: first checks
- Confirm which sensors are wired to Sensor Supply #2 on this specific engine, since the list varies by ECU connector configuration (oil pressure sensor, manifold air pressure sensor, low pressure fuel pressure sensor, VGT vane position sensor, fuel dosing pressure sensors, secondary analog throttle, or droop/ISOC governor switch)
- Inspect connectors and terminals at each sensor on the Sensor Supply #2 circuit for corrosion, moisture, bent pins, or a loose fit
- Check the wiring harness between the ECU and the affected sensors for chafing, pinches, or shorts to ground or power
- Verify that no aftermarket or extra devices have been tapped into the Sensor Supply #2 circuit, since an overloaded supply can trip a current limit shutdown
- Inspect the ECU connector faces (J1, J2, or J3 depending on configuration) for corrosion or a bad connection
- If wiring and sensors check out, consider ECU software or a bad ECU as the remaining possibilities
How the code clears
No separate clearing step is listed. The code is active whenever the ignition is on and the low voltage condition on the Sensor Supply #2 circuit is present, so it should clear on its own once the underlying wiring, sensor, or connector fault is repaired and the supply reads back within specification.
Frequently asked questions
What does SPN3510FMI4 mean on a John Deere engine?
It means the ECU detected the Sensor Supply #2 voltage, a 5-volt reference circuit used by several sensors, reading below 4.59 volts (or 4.6 volts in some ECU software versions) while the ignition was on.
Is SPN3510FMI4 a serious fault?
It is logged as a Warning level code. The ECU tries to keep the engine running and maintain its operating envelope, but engine performance may be affected until the low voltage condition is fixed.
Which sensors are affected by SPN3510FMI4?
Depending on the engine and ECU connector configuration, the sensors sharing this supply can include the engine oil pressure sensor, intake manifold air pressure sensor, low pressure fuel pressure sensor, VGT vane position sensor, fuel dosing inlet and outlet pressure sensors, secondary analog throttle, and droop/ISOC governor switch.
Can adding aftermarket sensors cause SPN3510FMI4?
Yes. If too many devices are connected to the Sensor Supply #2 circuit, the load can become too great and the ECU will activate a current limit shutdown on that supply, setting this code.
Will the engine shut down when this code is active?
The alarm level is Warning, and the ECU tries to maintain proper operating conditions rather than force a shutdown, though engine performance may be reduced.
Do I need a scan tool to diagnose SPN3510FMI4?
A scan tool helps confirm the active code and which ECU connector faces are populated on your engine, but the root cause is usually found by checking wiring, connectors, and the sensors sharing the Sensor Supply #2 circuit for shorts or corrosion.