New Holland TMF 163 – TMF: PTO Shaft rotation is detected when the PTO clutch is OFF

The control system is reading movement at the Power Take-Off (PTO) shaft even though the operator has disengaged the PTO switch.

• T4
• T5
• T6
• T7
• T8
• T9
• TG series
• TG210
• TG275
• TG305
• MXM series
• TM series
• TD5
• CR9090
• CX8080 Elevation
• CX8090 Elevation

1. 1

   Safely observe the PTO shaft when the tractor is running and the PTO is commanded OFF to determine if the shaft is actually rotating or if the sensor is just sending a false signal.

2. 2

   Check the wiring and connectors to the PTO speed sensor (PTO twist sensor) for unplugged connectors, broken wires, open circuits, or short circuits to ground.

3. 3

   Ensure the PTO Shaft Speed Sensor and the PTO Shaft Size Sensor connections have not been accidentally swapped during previous maintenance.

4. 4

   Test the PTO solenoid valve to check if the solenoid is shorted to 12V, failed open, or if the internal controller relay has failed closed.

5. 5

   If the shaft is physically turning, check for hydraulic pressure instability or valve faults causing unintended clutch engagement. If pressure drops but the shaft spins, the clutch plates may be warped.

1. 1

   Resolve Electrical/Sensor Faults

   If the shaft is not rotating but the code is active, the PTO speed sensor or its wiring is faulty. Repair any damaged wiring harnesses. If the wiring is intact, replace the PTO speed sensor.

2. 2

   Resolve Hydraulic/Solenoid Faults

   If the shaft is rotating and hydraulic pressure is still being supplied to the clutch pack when turned off, the PTO solenoid valve is likely stuck open or electrically shorted. Replace the PTO solenoid valve.

3. 3

   Resolve Mechanical Clutch Faults

   If the solenoid is functioning correctly and cutting off hydraulic pressure, but the shaft continues to rotate, the PTO clutch pack is suffering from mechanical wear (dragging plates). Disassemble, inspect, and rebuild the PTO clutch pack with new friction plates and seals.

4. 4

   Recalibration

   After replacing the sensor, solenoid, or rebuilding the clutch, perform a transmission/PTO clutch calibration routine via the tractor's display or service tool to clear the codes and relearn the engagement parameters.