New Holland 3731 – EDC: PTO switch : Diagnostic fault check for signal error of COM message

This code indicates that the control module is receiving an invalid, missing, or corrupted communication signal from the Power Take-Off (PTO) switch circuit. Rather than a mechanical failure of the PTO itself, this is an electrical or CAN bus communication error where the ECU cannot reliably determine if the operator is commanding the PTO to be ON or OFF.

• T6000 series
• TS series
• TM series
• Workmaster series
• TS90
• TS100
• TS110
• TS115
• Ford/New Holland 35 series
• Ford/New Holland 40 series
• Ford/New Holland 60 series

1. 1

   Check the PTO switch for physical damage, sticking, or broken detents. The switch should have a positive tactile feel when engaged and disengaged.

2. 2

   Remove the console trim and inspect the wiring harness connector at the back of the PTO switch. Look for corrosion, moisture ingress, pushed-out pins, or chafed wires.

3. 3

   Use a digital multimeter to test the switch's internal contacts. Verify that the circuit properly opens and closes when the switch is cycled.

4. 4

   If available, connect the CNH E.A.S.Y. diagnostic tool. Monitor the live data stream for the PTO switch state to see if the ECU registers the physical movement of the switch, which will confirm if the issue is the switch itself or a break in the CAN bus communication lines.

1. 1

   Disconnect power

   Turn off the tractor and disconnect the negative battery cable to prevent electrical shorts.

2. 2

   Access the switch

   Locate the PTO switch on the right-hand control console or dashboard. Carefully pry up or unscrew the console trim panel surrounding the switch to access the underside.

3. 3

   Disconnect harness

   Unplug the electrical wiring harness connector from the back of the PTO switch.

4. 4

   Remove old switch

   Depress the plastic retaining tabs on the sides of the switch body and push it upward/outward from the mounting panel.

5. 5

   Install new switch

   Insert the replacement PTO switch into the panel cutout and press down until the retaining tabs click securely into place.

6. 6

   Reconnect harness

   Plug the electrical wiring harness back into the switch.

7. 7

   Reassemble console

   Reinstall the console trim panel and secure any screws.

8. 8

   Test operation

   Reconnect the negative battery cable. Start the tractor and test the PTO engagement and disengagement to confirm the fault code is cleared and the PTO operates safely.