New Holland TMF 155 – TMF Controller / Armrest Controller: Auto PTO switch data failed in the Armrest controller

The controller is receiving an invalid signal, an out-of-range voltage, or an implausible state from the Auto PTO switch located in the cab. This can be caused by a failed internal switch contact, a wiring issue, or a switch interlock conflict (such as the cab switch and the remote fender switch sending conflicting signals simultaneously).

• New Holland T8000 Series (T8010, T8020, T8030, T8040, T8050)
• New Holland TG Series (TG245, TG305)
• New Holland TS-A Series (TS110A, TS115A, TS125A, TS135A)
• New Holland T6 Series
• New Holland T7 Series
• New Holland T8 Series
• New Holland T9 Series

1. 1

   Check for Interlock Conflicts: Ensure that the remote PTO fender switches are not stuck or being pressed at the same time as the cab switch.

2. 2

   Physical Inspection: Inspect the Auto PTO switch on the armrest console. Check if the rocker is physically broken, sticking, or jammed with dirt/debris.

3. 3

   Electrical Continuity Test: Remove the switch and use a multimeter to test for proper continuity across the switch terminals in both the engaged and disengaged positions.

4. 4

   Harness and Connector Check: Inspect the wiring harness between the Auto PTO switch and the TMF/Armrest controller. Look for chafed wires, pinched harnesses inside the armrest pivot point, or corroded connector pins.

1. 1

   Park the tractor on a level surface, turn off the engine, remove the key, and disconnect the negative battery cable to prevent electrical shorts.

   Park the tractor on a level surface, turn off the engine, remove the key, and disconnect the negative battery cable to prevent electrical shorts.

2. 2

   Carefully pry up or unscrew the trim panel on the armrest console to access the underside of the switch cluster.

   Carefully pry up or unscrew the trim panel on the armrest console to access the underside of the switch cluster.

3. 3

   Locate the Auto PTO switch and disconnect its electrical harness connector.

   Locate the Auto PTO switch and disconnect its electrical harness connector.

4. 4

   If the switch failed the continuity test, depress the retaining tabs on the sides of the switch body and push it up and out of the armrest bezel.

   If the switch failed the continuity test, depress the retaining tabs on the sides of the switch body and push it up and out of the armrest bezel.

5. 5

   If the switch tested fine, use a multimeter to check the wiring harness for continuity back to the TMF controller. Repair any broken or shorted wires found in the armrest loom.

   If the switch tested fine, use a multimeter to check the wiring harness for continuity back to the TMF controller. Repair any broken or shorted wires found in the armrest loom.

6. 6

   Snap the new OEM Auto PTO switch into the armrest panel.

   Snap the new OEM Auto PTO switch into the armrest panel.

7. 7

   Reconnect the electrical harness to the switch, ensuring the connector clicks securely into place.

   Reconnect the electrical harness to the switch, ensuring the connector clicks securely into place.

8. 8

   Reinstall the armrest console trim panel.

   Reinstall the armrest console trim panel.

9. 9

   Reconnect the battery, turn the ignition on, and use your diagnostic tool or the tractor's onboard display to clear the TMF 155 fault code.

   Reconnect the battery, turn the ignition on, and use your diagnostic tool or the tractor's onboard display to clear the TMF 155 fault code.

10. 10

    Start the tractor and test the Auto PTO function to ensure the PTO engages and disengages properly without triggering the code.

    Start the tractor and test the Auto PTO function to ensure the PTO engages and disengages properly without triggering the code.