Massey Ferguson 520240.31 – Engine ECU: Injector bank 0 short circuit

The engine control system has detected an electrical short circuit in the wiring or components controlling the first bank of fuel injectors, causing the engine to enter a limp mode (Degradation Level 3) which limits power to 50% and caps engine speed at 1500 RPM.

• 4710
• 7724S
• 5712SL
• Interim Tier 4 (2012-2015)
• 7722
• 7722S
• 7615
• 5613
• 5713SL
• 7720S
• 7716
• 7718
• T4
• 7715
• 5710SL
• 7726
• 7616
• 7618
• 5608
• 4708
• 7619
• 7626
• 7726S
• 7624
• 4707
• 4709
• 5711SL
• 7614
• 7718S
• 5610
• 7620
• 7719
• 7714
• 7716S
• T4 (2015-2021)
• 5612
• 7622
• 7720
• Tier 4 (2015-2021)
• 5611
• 7715S
• 5609
• 7724
• 7714S
• 7719S
• 5710 SL
• 5711 SL
• 5712 SL
• 5713 SL

1. 1

   Visually inspect the injector wiring harness for Bank 0 for chafed wires, melted insulation, or areas where the harness may be rubbing against the engine block.

2. 2

   Disconnect the harness from the Engine ECU and the injectors, and use a multimeter to test the Bank 0 injector circuits for a short to ground or a short to voltage.

3. 3

   Measure the internal resistance of each fuel injector on Bank 0 to check for an internally shorted fuel injector solenoid.

4. 4

   Inspect the pins at the Engine ECU and the injector connectors for corrosion, moisture, or bent pins.

1. 1

   Disconnect Power

   Always disconnect the tractor's battery before performing electrical repairs on the EEM system.

2. 2

   Repair/Replace Wiring

   If the diagnostic tests reveal a short in the wiring harness, repair the damaged section using proper automotive-grade heat-shrink connectors, or replace the entire injector wiring harness if the damage is extensive.

3. 3

   Replace Faulty Injector

   If an injector failed the resistance test (internal short), relieve the fuel system pressure, remove the faulty injector, and install a new OEM fuel injector.

4. 4

   Reassemble

   Reconnect all electrical connectors and the battery.

5. 5

   System Reset

   Clear the fault code. A system reset can be performed by turning the ignition OFF for a minimum of 60 seconds, then turning it back ON. Alternatively, use a dealer service tool (like WinEEM3/4) to clear the inactive code.

6. 6

   Test Run

   Start the tractor and verify that the engine operates at full power without the code returning.