John Deere 522559.03 – OIC (Operator Interface Control / Cab Module) or CCU (Chassis Control Unit): Diff Lock Switch On Floor Has Been Pressed For Too Long / Differential Lock Switch Circuit Voltage High

The control module has detected the floor-mounted differential lock switch has been closed (pressed) for an abnormally long time (typically more than 15 seconds after power-up). This registers as a 'Circuit Voltage High' error and disables the differential lock function.

• 6110M
• 6120M
• 6130M
• 6145M
• 6155M
• 6175M
• 6195M
• 6110R
• 6120R
• 6130R
• 6145R
• 6155R
• 6175R
• 6195R
• 6215R
• 5065M
• 5085M
• 5095M
• 5100M
• 5105M
• 5115M
• 7715
• 7815
• 7720
• 7820
• 7920

1. 1

   Check for physical obstructions like a floor mat, mud, or debris resting on and depressing the differential lock switch

2. 2

   Ensure the operator is not inadvertently resting their foot on the switch during operation

3. 3

   Power cycle the tractor to see if resetting communication messages clears the code

4. 4

   Test the switch for continuity to see if it has failed internally (shows closed circuit when not pressed)

1. 1

   Clear Debris

   Clean the floorboard area around the right-heel differential lock switch. Remove the floor mat and clear out any compacted dirt that might be jamming the switch plunger.

2. 2

   Test the Switch

   Disconnect the wiring harness from the floor switch. Test the switch with a multimeter.

3. 3

   Replace if Faulty

   If the switch is internally shorted (stuck closed), unbolt the switch assembly from the floorboard, install the replacement switch, and reconnect the harness.

4. 4

   Inspect Wiring

   If the switch tests fine, inspect the wiring harness running from the floor switch to the OIC/CCU. Look for rubbed or chafed wires causing a short-to-voltage.

5. 5

   Clear Codes

   Turn the key switch on and verify if the active code has moved to a stored/history state, or use a diagnostic tool to clear the code.