Massey Ferguson 520241.31 – Engine Control Unit (ECU): Injector bank 1 short circuit

The Engine Control Unit (ECU) has detected a short circuit in the wiring harness or within the fuel injectors themselves on Bank 1. This fault typically results in an immediate degradation of engine power (limp mode) or an engine shutdown to protect the system.

• 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
• 8650
• 8660
• 8670
• 8680
• 8690
• 5400 Series
• 6400 Series
• 7400 Series
• 8400 Series

1. 1

   Inspect the injector wiring harness for Bank 1 (specifically looking at the side of the valve cover where the harness connects) for chafing, melted insulation, or exposed wires causing a short to ground or battery.

2. 2

   Disconnect the injector connectors and the main EEM4 ECU connector. Inspect for corrosion, moisture, or bent pins.

3. 3

   Measure the resistance across the pins of each injector on Bank 1 to check for an internal short circuit within the injector coil.

4. 4

   Check the continuity of the wiring harness from the ECU to the injectors to isolate whether the short is in the harness or the injector itself.

1. 1

   Safety First

   Turn off the ignition and always disconnect the negative (-) battery cable before servicing the electrical system to prevent ECU damage.

2. 2

   Disconnect Modules

   Disconnect the EEM4 control unit main connector before working on the harness.

3. 3

   Access the Harness

   Locate the injector harness connections on the side of the valve cover.

4. 4

   Repair or Replace Harness/Injector

   If the wiring harness is damaged, repair the shorted section or splice in a new injector pigtail connector. If an injector failed the resistance test (internal short), remove the high-pressure fuel lines, connector tubes, and replace the faulty injector.

5. 5

   Reassembly

   Reconnect all injector harnesses and the main ECU connector. Reconnect the negative battery cable.

6. 6

   System Reset

   Turn the ignition off for a minimum of 60 seconds, then back on to reset the system. Clear the inactive fault codes using the EEM4 service tool (WinEEM4).