Massey Ferguson A.21.1B – Electronic Hydraulic Control (EHR) module or Tractor Control Unit (TCU): External Hydraulic Valve 2 Issue

Malfunction in the second external hydraulic remote valve (spool valve) circuit. Typically an electrical connection problem, a failure of the valve's solenoid coil, or an out-of-range reading from the spool position sensor.

• 5710SL
• 5711SL
• 5712SL
• 5713SL
• T4
• 4707
• 4708
• 4709
• 4710
• 5608
• 5609
• 5610
• 5611
• 5612
• 5613
• 7614
• 7615
• 7616
• 7618
• 7619
• 7620
• 7622
• 7624
• 7626
• 7714
• 7715
• 7716
• 7718
• 7719
• 7720
• 7722
• 7724
• 7726

1. 1

   Inspect the wiring harness leading to External Hydraulic Valve 2 for frayed wires, corrosion, or loose pins at the solenoid coil and the spool position sensor.

2. 2

   Use a multimeter to check the resistance of the valve's solenoid coil to ensure it is not shorted or open.

3. 3

   Verify that the spool position sensor is securely mounted and reading correctly, as a faulty sensor value will trigger this code.

4. 4

   Verify the transmission/hydraulic oil level and check the operation of the low-pressure switch, filtration switch, and filter clogging indicator to rule out a general hydraulic pressure or flow issue.

1. 1

   Depressurize the System

   Lower all implements to the ground, turn off the engine, and cycle the hydraulic levers/controls to relieve any residual pressure in the system.

2. 2

   Access the Valve Block

   Locate the external hydraulic valve block (usually at the rear of the tractor). Identify Valve #2.

3. 3

   Disconnect Electronics

   Carefully unplug the electrical connectors from the solenoid coil and the spool position sensor.

4. 4

   Remove the Component

   If replacing the sensor/coil: Unbolt the specific electronic component from the valve body. If replacing the entire spool valve: Disconnect the hydraulic lines (cap them to prevent contamination). Remove the mounting bolts securing the spool valve to the main block.

5. 5

   Install the New Part

   Fit the new component. If replacing the valve, ensure all O-rings and seals are properly seated and lubricated with clean hydraulic fluid. Torque mounting bolts to OEM specifications.

6. 6

   Reassembly and Testing

   Reconnect the hydraulic lines and electrical harnesses. Top up the transmission/hydraulic fluid.

7. 7

   Clear Codes

   Start the tractor, check for leaks, and use a compatible diagnostic tool to clear the A.21.1B DTC from the system.