New Holland 7017 – Transmission Motherboard (TMF) or Electronic Management Unit: Differential Lock Solenoid Open Circuit

The system has detected an open circuit in the differential lock solenoid, indicating a break or disconnection in the electrical path supplying power to it. This incomplete circuit prevents current from reaching and activating the solenoid, which disables the differential lock and reduces traction in slippery conditions. The root cause could be a broken wire, a loose or corroded connector, or a failed internal coil within the solenoid itself.

• T5.105
• T5.115
• T5.95
• T5.85
• T5.100
• TD55D
• TD60D
• TD65D
• TD70D
• TD75D
• TD80D
• TD85D
• TD90D
• TD95D
• TD5010
• TD5020
• TD5030
• TD5040
• TD5050
• TD5.65
• TD5.75
• TD5.80
• TD5.85
• TD5.90
• TD5.95
• TD5.100
• TD5.105
• TD5.110
• TD5.115
• TL65
• TL70
• TL75
• TL80
• TL85
• TL90
• TL95
• TL100
• TL70A
• TL80A
• TL90A
• TL100A
• TM115
• TM120
• TM125
• TM130
• TM135
• TM140
• TM150
• TM155
• TM165
• TM175
• TM190
• TS90
• TS100
• TS110
• TS115
• TS100A
• TS110A
• TS115A
• TS125A
• TS135A
• M100
• M115
• M135
• M160
• 8160
• 8260
• 8360
• 8560

1. 1

   Inspect the differential lock solenoid connector (often labeled C042) on the axle housing to ensure it is securely connected, free of damage, has correctly seated and tight pins, and check for corrosion or moisture.

2. 2

   Test the solenoid for an open circuit by disconnecting it and measuring resistance across its terminals with a multimeter (an infinite or O.L. reading indicates a failed coil).

3. 3

   Check the wiring harness for an open circuit by disconnecting the harness from both the solenoid and the electronic control unit, then testing continuity between the control unit's output pin and the solenoid connector pin.

1. 1

   Safety preparation

   Park the tractor on a level surface, engage the park brake, turn off the engine, and disconnect the battery before starting electrical work.

2. 2

   Access the solenoid

   Locate the solenoid on the differential housing. Clean the area around it to prevent dirt from entering the hydraulic system.

3. 3

   Remove the faulty solenoid

   Disconnect the electrical connector. Place a drain pan underneath to catch any fluid loss, then carefully unscrew the old solenoid from the housing.

4. 4

   Install the new solenoid

   Ensure the new solenoid's O-rings or seals are clean and lightly lubricated with new hydraulic fluid. Screw the new solenoid into place and tighten it to the manufacturer's specified torque.

5. 5

   Reconnect and test

   Reconnect the electrical connector and the battery.

6. 6

   Clear codes and verify

   Start the tractor. Use the dashboard interface or a diagnostic tool to clear the fault codes. Operate the differential lock switch to verify that the new solenoid functions correctly and the fault code does not reappear.