Massey Ferguson A.73.21 – Hydraulic control module or Autotronic ECU: External Hydraulic Valve 7 Issue

Malfunction in the 7th external hydraulic remote valve circuit, indicating an electrical fault (open circuit, short to ground, or short to power in the solenoid circuit), a missing or implausible sensor signal, or a mechanical condition where the valve is sticking, jamming, or experiencing irregular pressure.

• 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
• 7715S
• 7716
• 7716S
• 7718
• 7718S
• 7719
• 7720
• 7720S
• 7722
• 7722S
• 7724
• 7724S
• 7726
• 7726S

1. 1

   Verify that the hydraulic fluid is at the correct level and free of heavy debris or sediment, which can cause valves to stick or jam.

2. 2

   Inspect External Hydraulic Valve 7 for visible fluid leaks, physical damage, or loose linkages.

3. 3

   Use a multimeter to check the electrical connections to the valve's solenoid. Inspect the solenoid connector for corrosion, look for harness rub points, and test the coil resistance and ground integrity.

4. 4

   Inspect the fuses related to the hydraulic control module and ensure the alternator/voltage regulator is providing sufficient power, as low voltage can trigger false hydraulic codes.

1. 1

   Depressurize the System

   Power down the tractor and relieve all hydraulic system pressure before servicing the valve block.

2. 2

   Address Wiring Issues

   If the diagnostic checks revealed a damaged harness or corroded connector at Valve 7, repair the wiring or replace the connector plug.

3. 3

   Replace the Solenoid

   If the electrical circuit is intact but the solenoid failed the resistance test, remove and replace the electronic solenoid actuator on Valve 7.

4. 4

   Remove and Clean the Valve

   If the valve is mechanically sticking due to debris, remove the valve assembly. Flush the hydraulic lines and clean the valve body.

5. 5

   Replace the Valve

   If the valve body is heavily worn, leaking internally, or unresponsive, install a new external hydraulic valve assembly.

6. 6

   Reassemble and Refill

   Reconnect all hydraulic lines and electrical harnesses. Top off the system with manufacturer-recommended hydraulic fluid.

7. 7

   Clear Codes

   Use a compatible diagnostic tool to clear the A.73.21 DTC from the system and test the hydraulic remote to ensure proper operation.