Massey Ferguson 520218.31 – Engine Control Unit (ECU): ECU internal fault 0111
Issue description
Loss of synchronization sending bytes to the MM from CPU or an error during the MOCSOP (Test of redundant shut-off paths). Internal microprocessors within the engine controller are failing to communicate with each other properly or are failing their internal safety self-checks regarding emergency shut-off paths.
Applies to these machines
46 machines- 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
- MF 7722
- Dyna 4 models
Check the cause
Perform a system reset by turning the ignition off for a minimum of 60 seconds to allow the ECU to power down completely and clear temporary synchronization glitches.
Verify that the battery voltage is stable. Voltage drops or spikes can trigger false internal ECU faults (often accompanied by SPN 520200 codes).
Inspect the ECU main relays and wiring harnesses for any shorts to ground or high source, ensuring the ECU is receiving clean and consistent power.
Connect the AGCO Electronic Service Tool to read the active/inactive status of the code and check if an OEM software update is available to patch internal logic errors.
Repair steps
Perform a hard reset
Disconnect the battery or turn the ignition off for at least 60 seconds.
Disconnect the battery negative terminal
Ensure the system is completely powered down.
Disconnect the EEM4 control unit main connectors
Remove the faulty ECU
Unbolt and remove the faulty ECU from its mounting bracket on the engine block.
Install the replacement EEM4 ECU
Install the replacement EEM4 ECU and reconnect the main harnesses.
Reconnect the battery
Program the new ECU
Use the AGCO Electronic Service Tool to program the new ECU. You must flash it with the correct software, engine serial number data, and application specifications for the specific tractor.
Perform a functional test
Perform a functional test and clear any historical codes.
Parts you might need
(2)Engine Control Unit (ECU) / EEM4 Controller
V837073357AGCO Part Number. Must be ordered specific to the engine serial number and requires dealer programming via the AGCO Service Tool. Hardware reference: EEM4-H411.
Engine Control Unit (ECU) / EEM4 Controller
0281020170Bosch equivalent for EEM4-E401.
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