New Holland TMF 128 – TMF Module (Tractor Multifunction Controller): Aux 2nd Lower solenoid failed open or short circuit

The controller has commanded the Auxiliary #2 driver to turn on, but no electrical current is being sensed. This indicates that the retract/lower coil on the second auxiliary hydraulic valve has an open circuit or is shorted to ground.

• New Holland T8000 Series
• New Holland T8040
• New Holland T8050
• New Holland TG Series
• New Holland TG210
• New Holland TG230
• New Holland TG275
• New Holland TG285
• New Holland T6 Series
• New Holland T7 Series
• New Holland T8 Series
• New Holland T9 Series
• New Holland TM Series
• New Holland MXM Series
• New Holland SP280 Sprayer
• New Holland SP480 Sprayer

1. 1

   Verify if the Aux 2 lower/retract hydraulic function is completely inoperative

2. 2

   Inspect the wiring harness running from the TMF controller to the auxiliary valve stack at the rear of the tractor for chafed wires, pinched lines, or melted insulation

3. 3

   Disconnect the plug at the Aux 2 lower solenoid and TMF module connectors to check for water ingress, corrosion, or pushed-out pins

4. 4

   Measure the resistance of the Aux 2 lower solenoid coil (an infinite reading indicates an open internal coil, while 0 ohms indicates a dead short)

5. 5

   Check the harness for continuity between the solenoid connector and the TMF module to rule out a broken wire

6. 6

   Check the ground circuit for the solenoid to ensure it is not shorted to the tractor chassis

1. 1

   Disconnect Power

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

2. 2

   Wiring Repair (If Applicable)

   If the diagnostic checks revealed a broken or shorted wire in the harness, splice and repair the wire using weather-sealed (heat-shrink) butt connectors, or replace the damaged harness section.

3. 3

   Solenoid Replacement (If Applicable)

   If the solenoid coil failed the resistance test, locate the Aux 2 valve on the rear hydraulic remote stack. Remove the retaining nut or clip holding the lower/retract solenoid coil in place. Slide the faulty coil off the valve stem. (You typically do not need to open the hydraulic system to replace the electromagnetic coil). Slide the new OEM solenoid coil onto the stem and secure it with the retaining nut/clip.

4. 4

   Reassembly

   Reconnect the wiring harness to the solenoid, ensuring the weather-pack connector clicks firmly into place.

5. 5

   Testing

   Reconnect the battery, turn the key on, and clear the stored fault codes. Operate the Aux 2 remote to confirm the lower/retract function works and that TMF 128 does not return.