Massey Ferguson 520231.31 – Engine Control Unit (ECU): PTO Input Error

Indicates a fault in the digital input signal circuit for the PTO system, meaning the controller is receiving an implausible, missing, or erratic signal from the PTO switch or PTO speed sensor.

• 7616
• 5612
• 7622
• Interim Tier 4 (2012-2015)
• 7614
• 5611
• 7615
• 5610
• 5613
• 7620
• 5609
• 7618
• 5608
• 7619
• 7626
• 7624
• 8600 Series
• MF 8650
• MF 8660
• MF 8670
• MF 8680
• MF 8690
• 7600 Series
• 7700 Series
• MF 7614
• MF 7615
• MF 7616
• MF 7617
• MF 7618
• MF 7714
• MF 7715
• MF 7716
• MF 7717
• MF 7718
• 6400 Series
• 6600 Series
• 6700 Series
• 5400 Series

1. 1

   Inspect the PTO switch for physical damage, sticking, or liquid intrusion

2. 2

   Test PTO switch continuity using a multimeter to verify it opens and closes the circuit correctly when toggled

3. 3

   Check wiring harness and connectors between the PTO switch, PTO speed sensor, and ECU for chafed wires, short circuits to ground, or corroded pins

4. 4

   Inspect the inductive PTO speed sensor to see if the tip is covered in metallic debris or if the wiring is damaged

5. 5

   Verify digital input configuration to ensure the ECU hasn't lost its parameter settings

1. 1

   Power Down

   Turn off the tractor and disconnect the negative battery terminal to prevent electrical spikes.

2. 2

   Clean the Sensor

   Remove the PTO speed inductive sensor, wipe the magnetic tip clean of any metal shavings, and reinstall it to the specified depth/torque.

3. 3

   Replace Faulty Components

   If the PTO switch failed the continuity test, pop the switch out of the console bezel, disconnect the pigtail, and plug in a new OEM switch. If the wiring tested fine but the sensor is dead, replace the PTO speed sensor.

4. 4

   Restore Power & Clear Codes

   Reconnect the battery. Connect a diagnostic tool (such as AGCO EDT or WinEEM3s/WinEEM4 service tool) to the tractor's diagnostic port and clear the inactive 520231.31 fault code.

5. 5

   Operational Test

   Start the tractor and engage the PTO under a safe, no-load condition to verify the error code does not return and the PTO engages smoothly.