New Holland TMF 167 – TMF (Tractor Multi-Function) Controller: Current sensed when the PTO driver is off.

The system is detecting electrical current flowing through the Power Take-Off (PTO) driver circuit even though the controller has commanded the PTO to be in the "OFF" state. This indicates that voltage is bypassing the normal switching logic. This is typically caused by a short-to-power (12V) in the wiring harness between the controller and the PTO solenoid, a failed PTO solenoid, or an internal hardware failure within the controller itself.

• T8010
• T8020
• T8030
• T8040
• T8050
• TG215
• TG245
• TG275
• TG305
• T6
• T7
• T9
• TS
• TM

1. 1

   Visually inspect the wiring harness running from the TMF controller to the PTO solenoid for chafing, melted insulation, or pinch points that could cause a short to a 12V power source.

2. 2

   Disconnect the PTO solenoid and inspect the pins for corrosion, moisture, or debris that could be bridging the connections.

3. 3

   With the tractor key ON but the PTO switch in the OFF position, use a multimeter to probe the PTO solenoid connector on the harness side. There should be no voltage. If 12V is present, there is a short to power in the harness or the TMF controller is internally shorted.

4. 4

   Disconnect the harness at the TMF controller and test the specific pin for the PTO driver. If 12V is present at the pin when the PTO is commanded off, the TMF controller has failed internally.

1. 1

   Isolate the Fault

   Turn the tractor off and disconnect the PTO solenoid. Turn the key back on. If the fault code changes to an open circuit code (e.g., TMF 166 "PTO Driver is on and no current is sensed"), the issue is likely a short within the PTO solenoid itself.

2. 2

   Replace the Solenoid

   If the solenoid is internally shorted, remove the retaining nut/bolt, slide the old coil off the valve stem, install the new PTO solenoid coil, and reconnect the harness.

3. 3

   Trace and Repair Wiring

   If 12V was found at the harness connector during the diagnostic checks, trace the wire back to the TMF controller. Locate the damaged section of the wire where it is shorting to a power wire. Splice and heat-shrink the damaged wires, or replace the PTO solenoid wire assembly entirely.

4. 4

   Replace TMF Controller

   If the wiring harness tests perfectly fine but the TMF controller is outputting constant voltage to the PTO driver pin, the TMF controller must be replaced. Note: A new TMF controller will require configuration and calibration using the dealer service tool.

5. 5

   Clear Codes and Test

   Reconnect all components, clear the fault codes from the instrument cluster/display, and cycle the PTO switch to verify the PTO engages and disengages properly without throwing TMF 167.