Massey Ferguson 05.01.51 – Transmission Module (TRANS or TRANS1): Issue With Signal From Diff Lock Button On Side Pillar Dyna VT

The system has detected a faulty signal from the 100% differential lock button (or key) located on the cab's side pillar. When this code is active, the manual 100% differential lock function is disabled, and only the "Differential lock automatic mode" function remains available.

• 7714
• 7715
• 7715S
• 7716
• 7716S
• 7718
• 7718S
• 7719
• 7720
• 7720S
• 7722
• 7722S
• 7724
• 7724S
• 7726
• 7726S
• Tier 4 (2015-2021)
• 7600 Series Interim Tier 4 (2012-2015)
• 7614
• 7615
• 7616
• 7618
• 7619
• 7620
• 7622
• 7624
• 7626
• 6600 series
• 7700 series
• 8700 series

1. 1

   Inspect the wiring harness leading to the B-pillar (side pillar) switch panel for any breaks, chafing, or pinched wires.

2. 2

   Disconnect the plug at the side pillar switch panel and check for loose pins, moisture, or corrosion.

3. 3

   Test the differential lock button (often integrated into a membrane/foil keypad on the pillar) for proper electrical continuity when pressed.

1. 1

   Power Down

   Turn off the tractor ignition and disconnect the negative battery terminal to prevent electrical shorts.

2. 2

   Access the Panel

   Locate the switch control panel on the right-hand B-pillar inside the cab.

3. 3

   Disconnect

   Carefully pry or unscrew the switch panel from the pillar housing and disconnect the main wiring harness connector from the back of the unit.

4. 4

   Repair Wiring (If Applicable)

   If your diagnostic checks revealed damaged wiring or a corroded connector, repair the affected wires or repin the connector.

5. 5

   Replace the Switch Unit

   If the button itself failed the continuity test (common with membrane foil switches), the switch control unit must be replaced. Connect the wiring harness to the new switch panel.

6. 6

   Reassemble

   Snap or screw the new switch panel back into the side pillar housing.

7. 7

   Clear Codes

   Reconnect the battery, turn on the ignition, and use a dealer diagnostic tool to clear the 05.01.51 code from the Transmission Module (TRANS).

8. 8

   Verify Operation

   Start the tractor and test both the automatic and 100% manual differential lock functions to ensure proper engagement and disengagement.