Massey Ferguson T155 – Transmission Control Unit (TCU) / Autotronic 5: Issue With Range 2 Switch Signal. (TRANS)

Short circuit to 0 V on the Range 2 switch circuit (component X489).

• 5608
• 5609
• 5610
• 5611
• 5612
• 5613
• 5425
• 5455
• 5460
• 5613 iT4
• 6480
• 6614
• 6615
• 6713 S
• 6718 S
• 7614
• 7615
• 7616
• 7618
• 7624
• 7718
• 8727

1. 1

   Inspect the wiring harness and connectors leading to the Range 2 switch (X489) on the transmission housing for chafed wires, melted insulation, or pinched harnesses that could cause a short to ground.

2. 2

   Disconnect the electrical connector at the switch and use a multimeter to check for continuity to ground on the signal wire. If grounded while disconnected, the harness is faulty; if not, the switch is internally shorted.

3. 3

   Inspect the pins at the Autotronic 5 transmission controller for corrosion, moisture ingress, or bent pins that could bridge the circuit to ground.

1. 1

   Power down the tractor, remove the key, and disconnect the negative battery terminal.

2. 2

   Locate the transmission range switch assembly on the side of the transmission housing.

3. 3

   Disconnect the electrical connector from the faulty Range 2 switch.

4. 4

   If the diagnostic tests pointed to a harness issue, repair the damaged section of the wiring harness and apply heat-shrink tubing to protect it from the elements.

5. 5

   If the switch itself is internally shorted, unbolt and remove the faulty transmission range switch.

6. 6

   Clean the mounting surface on the transmission housing.

7. 7

   Install the new transmission range switch and tighten to OEM torque specifications.

8. 8

   Reconnect the electrical harness, ensuring the connector clicks securely into place.

9. 9

   Reconnect the battery, turn on the ignition, and use a diagnostic tool to clear the T155 fault code from the Autotronic 5 controller.

10. 10

    Test drive the tractor, shifting through all transmission ranges to ensure proper engagement and verify that the code does not return.