Massey Ferguson E520298.31 – Engine Control Unit (ECU): CAN BUS Fault (ECU) / ECU internal fault 0133

Indicates a CAN bus diagnostic error where the module is experiencing an internal communication failure. All periodic TX [transmit] messages cannot be allocated a send buffer in at least one timeslot, meaning the controller is internally failing to process and transmit its required network messages onto the tractor's CAN bus system.

• 7616
• 5612
• 7622
• Interim Tier 4 (2012-2015)
• 7614
• 5611
• 7615
• 5610
• 5613
• 7620
• 5609
• 7618
• 5608
• 7619
• 7626
• 7624
• 4700 Series
• MF 4707
• MF 4708
• MF 4709
• MF 4710
• 5600 Series
• MF 5608
• MF 5609
• MF 5610
• MF 5611
• MF 5612
• MF 5613
• 5700 SL Series
• MF 5710 SL
• MF 5711 SL
• MF 5712 SL
• MF 5713 SL
• 7600 Series
• MF 7614 through 7626
• 7700 Series
• MF 7714 through 7726S
• 8600 Series

1. 1

   System Scan: Connect the AGCO Electronic Diagnostic Tool (EDT) or WinEEM3/WinEEM4 Service Tool via a CANUSB interface to read all active and stored faults.

2. 2

   Voltage Check: Verify battery voltage. Voltage spikes or drops (below 7.8V or above 17V/32V) can disable ECU power stages and trigger internal communication errors.

3. 3

   Wiring & Harness Inspection: Inspect the main engine wiring harness and the ECU connector pins. Look for moisture, corrosion, or backed-out pins that could disrupt the CAN High and CAN Low signals.

4. 4

   CAN Bus Resistance Test: With the battery disconnected, measure the resistance across the CAN bus network at the diagnostic port. It should read approximately 60 ohms. If it reads 120 ohms or higher, there is an open circuit or a failed terminating resistor on the network, which can cause buffer overloads in the ECU.

1. 1

   Disconnect Power

   Disconnect the tractor's battery to prevent electrical spikes.

2. 2

   Clean Connections

   Disconnect the multi-pin connectors at the Engine ECU. Clean the contacts with electrical contact cleaner and apply dielectric grease. Reconnect and ensure the locking mechanisms are fully seated.

3. 3

   Clear and Retest

   Reconnect the battery. Use the AGCO EDT to clear the E520298.31 fault code. Cycle the key and run the engine.

4. 4

   Software Update

   If the code returns immediately as an active 'ECU internal fault 0133', check if there is a software update available for the ECU. Sometimes, buffer allocation errors are resolved by flashing the ECU with updated AGCO firmware.

5. 5

   Replace the ECU

   If the wiring is sound and software updates fail or are unavailable, the ECU has suffered a permanent internal hardware failure. Remove the defective Engine ECU.

6. 6

   EOL Programming

   Install the replacement ECU. You must use the AGCO EDT / FenDias software to perform EOL (End Of Line) programming. This flashes the correct engine maps, pairs the ECU to the tractor's immobilizer/CAN network, and calibrates the injector codes.