Massey Ferguson 520226.31 – Engine Control Unit (ECU): Engine Module Internal Issue (ECU)

The Engine Control Unit failed its internal self-diagnostic check regarding the redundant engine shut-off path (MOCSOP Diagnostic error or ECU internal fault 0119). It is an internal hardware or software failure within the module itself.

• 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
• Massey Ferguson 7600 Series (Interim Tier 4, 2012-2015)
• MF 7614
• MF 7615
• MF 7616
• MF 7618
• MF 7619
• MF 7620
• MF 7622
• MF 7624
• MF 7626
• 4700 series
• 5600 series
• 5700 SL series
• 7700 series

1. 1

   Verify that the tractor's battery voltage is stable and that the main power and ground connections to the Engine ECU are clean and tight to rule out voltage spikes or drops.

2. 2

   Inspect the ECU wiring harness connectors for water intrusion, corrosion, or bent pins.

3. 3

   Clear the DTC using an AGCO diagnostic tool and cycle the ignition. If the code immediately returns upon key-on, the internal fault is hard-set.

1. 1

   Disconnect Power

   Turn off the ignition and disconnect the tractor's battery (negative terminal first) to prevent electrical arcing.

2. 2

   Locate the ECU

   Locate the Engine Control Unit, which is typically mounted directly to the side of the AGCO Sisu engine block.

3. 3

   Disconnect Harness

   Carefully release the locking levers on the main wiring harness connectors and unplug them from the ECU.

4. 4

   Remove the ECU

   Remove the mounting bolts securing the ECU to the engine block/bracket and remove the module.

5. 5

   Install the New ECU

   Mount the replacement ECU and secure the bolts. Reconnect the wiring harness, ensuring the locking levers click fully into place.

6. 6

   Reconnect Power

   Reconnect the battery.

7. 7

   Programming

   An authorized dealer must connect the AGCO Electronic Diagnostic Tool (EDT) to flash the ECU with the correct software and engine parameters for your specific tractor model.