Massey Ferguson 4.02.6A – TRANS1 (Autotronic 5): Issue With Range 4 Solenoid Valve (TRANS1)

Electrical fault in the L55 circuit (Range 4 Solenoid Valve). The system detects an open circuit, a short circuit to +12 V or to ground (0 V), or measured current outside the specified operating range (e.g., drawing less than 40 mA or exceeding the maximum possible 1.4 A).

• 5710SL
• 5711SL
• 5712SL
• 5713SL
• T4
• 7614
• 7615
• 7616
• 7618
• 7619
• 7620
• 7622
• 7624
• 7626
• 7714
• 7715
• 7715S
• 7716
• 7716S
• 7718
• 7718S
• 7719
• 7720
• 7722
• 7724
• 7726
• 5400 Series
• 6400 Series

1. 1

   Harness Inspection: Inspect the wiring harness between the Autotronic 5 (TRANS1) controller and the L55 solenoid valve on the transmission block. Look for chafed wires, melted insulation, or pinched lines that could cause a short to ground or +12V.

2. 2

   Connector Check: Disconnect the L55 solenoid and check the pins for corrosion, moisture, or poor terminal tension.

3. 3

   Coil Resistance Test: Use a multimeter to test the resistance of the L55 solenoid coil. An infinite reading indicates an internal open circuit, while a reading near zero indicates an internal short.

4. 4

   Switch Consistency Check: Verify the operation of the Range 4 position switch (designated as L59). The Autotronic 5 module monitors both the L55 valve and the L59 switch; inconsistencies between the commanded valve state and the switch feedback can sometimes trigger related range errors.

5. 5

   Voltage Supply: Ensure the Autotronic 5 controller is receiving proper ignition voltage (+APC > 7 V), as low voltage can cause erratic solenoid behavior.

1. 1

   Preparation

   Park the tractor on a level surface, engage the parking brake, and turn off the engine. Relieve any residual hydraulic pressure in the transmission control circuit.

2. 2

   Locate the Valve Block

   Locate the transmission range control valve block on the side of the gearbox housing. You will see a cluster of solenoids designated L52 (Range 1), L53 (Range 2), L54 (Range 3), and L55 (Range 4).

3. 3

   Disconnect Electrical

   Unplug the electrical connector specifically routed to the L55 solenoid.

4. 4

   Remove the Solenoid

   Remove the retaining screws and the flange holding the L55 solenoid valve in place.

5. 5

   Install New Valve

   Lubricate the O-rings on the new solenoid valve with clean transmission fluid. Insert the new L55 solenoid into the valve block.

6. 6

   Secure and Reconnect

   Reinstall the flange and tighten the retaining screws to the OEM specified torque. Reconnect the electrical harness.

7. 7

   Clear Codes

   Connect a diagnostic laptop with Massey Ferguson WINTEST software (or an equivalent diagnostic tool) to the 16-pin diagnostic port. Clear the 4.02.6A fault code from the Autotronic 5 memory.

8. 8

   Test

   Start the tractor and cycle through the transmission ranges to ensure Range 4 engages smoothly without throwing a code.