John Deere 127 – ACU: Feeder House Pressure With Separator Off

The Armrest Control Unit (ACU) has detected pressure in the five-speed feeder house hydraulic circuit while the separator is not engaged. Because hydraulic pressure should only be present when the separator is active, this indicates an inconsistency between the pressure reading and the operational status of the separator. This is typically caused by a faulty pressure switch providing a false positive signal or a short in the electrical circuit.

• S660
• S670
• S680
• S690

1. 1

   Verify that the separator is not running and the separator engage switch is in the 'off' position.

2. 2

   Visually inspect the five-speed feeder house pressure switch for damage, corrosion, or fluid leaks.

3. 3

   Examine the wiring and connector to the pressure switch for damage, corrosion, or loose connections.

4. 4

   Perform a voltage test at the pressure switch connector with the key 'on' and engine off; voltage present may indicate a short in the wiring.

5. 5

   Perform a continuity test across the disconnected pressure switch terminals; continuity without pressure indicates a switch stuck in the closed position.

1. 1

   Safety First

   Park the combine on a level surface, lower all equipment to the ground, stop the engine, and remove the key.

2. 2

   Relieve Hydraulic Pressure

   Before disconnecting any hydraulic components, relieve the pressure in the system.

3. 3

   Access the Pressure Switch

   Locate the faulty pressure switch.

4. 4

   Disconnect Electrical Connector

   Carefully disconnect the wiring harness from the pressure switch.

5. 5

   Remove the Old Switch

   Using the appropriate wrench, unscrew the old pressure switch from its port. Be prepared for a small amount of residual hydraulic fluid to leak out.

6. 6

   Install the New Switch

   Screw the new pressure switch into the port and tighten it to the manufacturer's specified torque.

7. 7

   Reconnect Electrical Connector

   Connect the wiring harness to the new pressure switch.

8. 8

   Clear Fault Codes

   Use a diagnostic tool to clear the fault code from the control unit's memory.

9. 9

   Test the System

   Start the combine and operate the separator and feeder house functions to ensure that the fault does not reappear.