John Deere 521407.31 – SCO: SCV XIV Control Lever Command Missing

The controller is no longer receiving the position signal or command input from the Selective Control Valve (SCV) 14 control lever/switch located on the tractor's CommandARM console.

• 6110R
• 6120R
• 6130R
• 6145R
• 6155R
• 6175R
• 6195R
• 6215R
• 8R Series
• 8RT Series
• 8245R
• 8400R

1. 1

   Power Cycle: Turn off the tractor, cycle the key switch, and restart the engine to see if the fault clears or is a temporary glitch.

2. 2

   Physical Inspection: Check the SCV 14 control lever on the CommandARM. Verify if it feels physically broken, loose, or lacks standard resistance.

3. 3

   Wiring & Connections: Inspect the wiring harness and the electrical connector directly beneath the SCV 14 switch inside the CommandARM console. Look for pinched wires, loose connector seating, or corrosion.

1. 1

   Preparation

   Park the tractor on a level surface, engage the park brake, and turn off the engine.

2. 2

   Access the Console

   Remove the lid/cover from the top of the CommandARM armrest.

3. 3

   Remove Console Fasteners

   Locate and remove the mounting bolts (typically three) from the bottom of the console.

4. 4

   Lift the Housing

   Carefully lift the top half of the console to expose the underside of the SCV switches and levers.

5. 5

   Disconnect the Switch

   Locate the SCV 14 switch assembly. Unplug its specific wiring harness connector.

6. 6

   Remove the Switch

   The SCV switches are held in place by a couple of mounting screws. Remove these screws and pull the faulty switch out.

7. 7

   Installation

   Seat the new SCV switch, secure it with the screws, and plug the wiring harness back in.

8. 8

   Reassembly

   Lower the top half of the console, reinstall the bottom bolts, and replace the armrest lid. Turn on the tractor and test the SCV 14 function to ensure the code has cleared.