Massey Ferguson 520248.31 – Engine Controller (EEM4): Engine controller internal error / ECU internal fault 0124

Reported SPI and COM-Errors of a Cy146, indicating a fatal internal hardware or communication failure within the Cy146 microchip/processor inside the engine control module.

• 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
• 8600 Series
• 8700 Series

1. 1

   Perform a system hard reset by turning the ignition OFF for a minimum of 60 seconds, then turn it back on to see if the fault clears

2. 2

   Verify the main power and ground supplies (12V supply lines) to the EEM4 controller to rule out voltage spikes or poor grounds triggering false internal faults

3. 3

   Perform an ECU swap test with another functional EEM4 controller; if the system functions normally with the replacement, the original ECU is defective

1. 1

   Disconnect battery

   Disconnect the tractor's battery (negative terminal first) to prevent electrical shorts.

2. 2

   Locate ECU

   Locate the EEM4 Engine ECU, which is typically isolation-mounted directly to the side of the AGCO Power engine block.

3. 3

   Unplug connectors

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

4. 4

   Remove ECU

   Remove the mounting bolts securing the ECU to the engine block and remove the defective unit.

5. 5

   Install replacement ECU

   Install the replacement EEM4 ECU and torque the mounting bolts to OEM spec.

6. 6

   Reconnect harnesses

   Reconnect the wiring harnesses, ensuring the locking levers are fully seated and secure.

7. 7

   Reconnect battery

   Reconnect the battery.

8. 8

   Program ECU

   Connect the AGCO Electronic Diagnostic Tool (EDT) or WinEEM4 Service Tool via the CANBUS diagnostic port to flash the ECU with the correct engine parameters, End Of Line (EOL) programming, and software specific to the tractor's chassis/serial number.