New Holland TMF 12 – TMF (Tractor Multi-Function) controller: Communication lost with the armrest controller

The main Tractor Data Bus (CAN bus) has stopped receiving communication signals from the Armrest Controller (ARU). Depending on the specific tractor configuration, this same communication loss might also trigger related codes such as TRANS 135, PERF 12011, or Hitch 12031.

• TG210
• TG230
• TG245
• TG255
• TG285
• T7550
• T7520
• T8.360
• T9.390
• T9.450
• T9.505
• T9.560
• T9.615
• T9.670
• TM175
• MXM models

1. 1

   Verify power and ground to the armrest controller by checking for an active status light on the module.

2. 2

   Inspect connector C137 to ensure it is fully seated, checking data bus wires (cavities 4 and 5) and power/ground wires (cavities 12 and 11) for corrosion or pushed pins.

3. 3

   Check the wiring harness at the back of the armrest for chafing, specifically near the P-clamp that fastens the harness.

4. 4

   Test CAN bus terminators (especially on older models like the TG255) for broken solder joints by checking the resistance coming out of the terminators.

1. 1

   Repair Wiring

   If chafing or broken wires are found near the P-clamp or connector C137, repair the wiring harness and secure it to prevent future rubbing.

2. 2

   Replace Terminators

   If the tractor uses the older 'active' style CAN terminators and they are failing, replace them with the updated, simpler 2-wire resistor terminators.

3. 3

   Replace the Armrest Controller

   If wiring and terminators are good but the controller has no power light or will not communicate, remove the faulty armrest controller and install a replacement unit.

4. 4

   Software Calibration

   Connect the New Holland Electronic Service Tool (EST), capture the new controller on the network, and download the correct software/firmware for your specific tractor model.