Massey Ferguson E520228.12 – Engine Control Unit (ECU) / EEM4: Engine Module Internal Issue

The CY320 is an internal power supply monitoring chip located on the engine controller's circuit board. When this code is logged, it means the ECU has detected an internal hardware failure, communication loss, or voltage irregularity with this specific microchip.

• 7616
• 5612
• 7622
• Interim Tier 4 (2012-2015)
• 7614
• 5611
• 7615
• 5610
• 5613
• 7620
• 5609
• 7618
• 5608
• 7619
• 7626
• 7624
• 7714
• 7715
• 7716
• 7718
• 7719
• 7720
• 7722
• 7724
• 7726
• 4707
• 4708
• 4709
• 4710
• 5710 SL
• 5711 SL
• 5712 SL
• 5713 SL

1. 1

   Clear and Retest: Using the AGCO Electronic Diagnostic Tool (EDT), save the error log and then erase it. Restart the ECU. If the fault returns immediately upon key-on, the internal CY320 chip failure is confirmed.

2. 2

   Check External Power/Ground: Verify the main power and ground harness connections to the EEM4 controller. A severe external voltage drop or short can sometimes cause the internal CY320 chip to report a supply error.

3. 3

   Test with a Known-Good ECU: Test the system with a replacement EEM4 controller. If the system is functional and the fault is not active with the test ECU, the original ECU is definitively defective.

1. 1

   Connect diagnostic tool

   Connect the AGCO EDT device to the tractor and open the software.

2. 2

   Save engine log

   Open the "Diagnostic Test" page, select "Save & Upload Engine Log", and save the engine log information to your desktop.

3. 3

   Save IQA codes

   Navigate to the "Calibration" tab and save the IQA (Injector Quantity Adjustment) codes. You will need these to program the new ECU.

4. 4

   Start ECU replacement procedure

   Open "Configuration", select "Engine ECU Replacement", and click start.

5. 5

   Deactivate old unit

   Click "Continue Step 1", turn the ignition switch to OFF, and wait exactly 2 minutes for power to be completely cut from the tractor's control units.

6. 6

   Remove old ECU

   Physically disconnect the wiring harnesses and remove the old EEM4 unit from the engine block.

7. 7

   Install new ECU

   Install the new EEM4 spare part and reconnect the harnesses.

8. 8

   Read new ECU serial number

   Turn the ignition switch to ON. The EDT will read the serial number of the new EEM4 unit.

9. 9

   Activate and program new ECU

   Follow the on-screen EDT prompts to activate the new unit, flash the correct software, and write the saved IQA codes to the new controller.