John Deere Engines SPN733FMI2 Fault Code: Rack Position Error with Engine Off
Rack Position Error with Engine Off · ai-assisted, editor-reviewed · Last updated 2026-07-13
TL;DR
SPN 733 FMI 2 means the ECU sees the fuel injection pump rack sitting away from the zero fuel delivery position while the ignition is ON and the engine is OFF. The engine may still run fine or may show lower power, depending on the cause.
Medium severity. The engine can still run, sometimes normally, but a rack that will not return to zero fuel delivery points to a mechanical or electrical problem inside or around the injection pump that should be diagnosed before it worsens or leaves you with reduced power in the field.
What does John Deere Engines error code SPN733FMI2 mean?
This code is tied to the injection pump's rack position sensor and rack actuator solenoid. The ECU controls how much fuel the pump delivers by energizing the rack actuator solenoid inside the injection pump, driving the rack toward full fuel delivery. When current is not applied, the rack is spring loaded back to the zero fuel delivery position.
The rack position sensor, also inside the injection pump, reports the rack's actual position back to the ECU so the controller can confirm the rack went where it was commanded. SPN 733 FMI 2 sets specifically when, with the ignition ON and the engine OFF, the sensor reports the rack is not sitting at zero fuel delivery like it should be at rest.
Depending on what is causing this mismatch, the engine may run normally or it may deliver lower power than normal. Either way, something is preventing the rack from returning fully to its spring-loaded rest position, and that is worth chasing down.
Common causes of SPN733FMI2
- Dirt, damage, or poorly positioned terminals on the ECU 30-way connector or the injection pump's 6-way connector
- Air trapped in the injection pump
- A stuck rack inside the injection pump
- A bad injection pump
How to troubleshoot John Deere Engines SPN733FMI2: first checks
- Inspect the ECU 30-way connector and the injection pump 6-way connector for dirt, corrosion, damaged pins, or terminals that are not fully seated
- Use the JT07328 Connector Adapter Test Kit to check connector terminals rather than forcing probes directly into the terminals, which can damage them
- Check for air in the injection pump and bleed the fuel system if air is suspected
- Look for signs the rack is physically stuck or sluggish inside the injection pump rather than moving freely to its spring-loaded rest position
- If connectors, air, and a stuck rack are ruled out, suspect the injection pump itself as faulty
How the code clears
No separate clearing step is listed for this code. Repair the underlying cause, whether that is a connector issue, trapped air, a stuck rack, or a failed injection pump, then confirm with a code reader whether the fault clears with ignition ON and engine OFF.
Frequently asked questions
What does SPN 733 FMI 2 mean on a John Deere engine?
It means that with the ignition ON and the engine OFF, the injection pump's rack position sensor is reporting that the rack is not sitting at the zero fuel delivery position, which is where it should rest when no current is applied to the rack actuator solenoid.
Can I keep driving or working with SPN 733 FMI 2 active?
The engine may run normally or it may deliver lower power than normal, depending on the cause. Since it points to a mechanical or electrical issue at the injection pump, it is best to get it diagnosed rather than ignore it, especially if you notice reduced power.
What usually causes SPN 733 FMI 2?
Listed causes include dirty, damaged, or poorly positioned terminals on the ECU 30-way connector or the injection pump 6-way connector, air in the injection pump, a rack stuck inside the injection pump, or a bad injection pump.
Why does John Deere recommend a special tool for checking connectors?
John Deere warns not to force probes into connector terminals because it can damage them. The JT07328 Connector Adapter Test Kit is meant to let you take measurements at the connectors without damaging the terminals.
Is there a specific reset procedure for SPN 733 FMI 2?
No reset procedure is listed for this code. The expectation is that once the underlying cause, whether connector, air, stuck rack, or pump, is repaired, the code should no longer be present when checked with the ignition ON and engine OFF.
Does SPN 733 FMI 2 always cause a loss of power?
Not necessarily. The engine may deliver lower power than normal or may run normally, depending on what is causing the rack position mismatch.