Massey Ferguson 520225.31 – Engine Control Unit (ECU): ECU internal fault 0118

This is a critical internal hardware failure related to the monitoring concept of the redundant shut-off paths (MOCSOP). It indicates that a very low-level safety function within the ECU hardware itself has failed its internal diagnostic self-test.

• 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
• 7700 series
• 8600 series
• Dyna-4 transmission models
• 211p

1. 1

   Perform a system reset by turning off the ignition for a minimum of 60 seconds to allow the ECU to power down completely, then turn it back on to check if the code changes from Active to Stored/Inactive.

2. 2

   Check the main power and ground pins at the ECU harness to rule out voltage spikes, severe voltage drops, or a failing alternator triggering false internal faults.

3. 3

   Use the AGCO WinEEM4 Service Tool or AGCO EDT to clear the code; if it returns immediately upon key-on or engine cranking, the ECU hardware is permanently damaged.

1. 1

   Disconnect Power

   Disconnect the negative, then positive battery cables to prevent electrical arcing.

2. 2

   Locate the ECU

   Locate the EEM4 Engine Control Unit, which is typically mounted directly to the side of the engine block.

3. 3

   Remove the ECU

   Disconnect the primary and secondary wiring harness connectors from the ECU. Unbolt the module from its mounting bracket and remove it.

4. 4

   Install the New ECU

   Mount the replacement ECU and securely reconnect the wiring harnesses.

5. 5

   Reconnect Power

   Reconnect the battery cables (positive first, then negative).

6. 6

   Programming/Calibration

   Connect the AGCO WinEEM3/WinEEM4 Service Tool (or AGCO EDT) to the tractor's diagnostic port and flash the ECU with the correct software file matching the specific engine serial number and tractor model. The machine will not run until this calibration is performed.