Massey Ferguson T125 – TRANS2 (Transmission ECU / Autotronic 5): Issue With Multiple Range Switches Engaged (TRANS2)

The transmission controller detects an impossible state where multiple range switches are sending an "engaged" signal simultaneously. This is specifically triggered when the controller sees both the X490 (Range 3 switch) and X491 (Range 4 switch) engaged at the same time, or when there is an inconsistency between the physical switch states and the commanded range solenoid valves.

• 7616
• 5612
• 7622
• Interim Tier 4 (2012-2015)
• 7614
• 5611
• 7615
• 5610
• 5613
• 7620
• 5609
• 7618
• 5608
• 7619
• 7626
• 7624
• 5410
• 5420
• 5425
• 5435
• 5440
• 5445
• 5450
• 5455
• 5460
• 5465
• 5470
• 5475
• 5480
• 5709
• 5710
• 5711
• 5712
• 5713
• 6445
• 6455
• 6460
• 6465
• 6470
• 6475
• 6480
• 6485
• 6490
• 6495
• 6497
• 6499
• 6612
• 6613
• 6614
• 6615
• 6616
• 6711
• 6712
• 6713
• 6714
• 6715
• 6716
• 6718
• 7714
• 7715
• 7716
• 7718
• 7719
• 7720
• 7722
• 7724
• 7726

1. 1

   Inspect the wiring harness and connectors between the transmission range switches (specifically X490 and X491) and the Autotronic 5 controller for chafing, pinched wires, or short circuits to ground or +12V.

2. 2

   Test the continuity of the X490 (Range 3) and X491 (Range 4) switches. They should only show 12V when their respective range is physically engaged.

3. 3

   Verify that the corresponding range solenoid valves (X484, X485, X486, X487) are operating correctly and not sticking, which could cause the selector rails to physically engage multiple ranges or fail to disengage.

1. 1

   Locate the Switches

   Locate the transmission range position switches on the right-hand side of the gearbox.

2. 2

   Disconnect and Inspect

   Disconnect the electrical connectors for the X490 and X491 switches. Inspect the pins for corrosion or damage.

3. 3

   Test/Replace Faulty Switch

   If a switch is internally shorted (sending a constant 12V signal regardless of selector rail position), it must be replaced. Unscrew the faulty switch from the transmission housing.

4. 4

   Install New Switch

   Install the new OEM transmission range switch. Ensure the switch is properly seated so that the internal pins can be pressed by the selector rail.

5. 5

   Clear Codes and Test

   Reconnect the wiring harness, clear the T125 fault code from the Autotronic 5 ECU, and test drive the tractor through all ranges to ensure the code does not return.