John Deere 000186.01 – CCU / BCU / RPT: Rear PTO Speed Too Slow During Start Up

The tractor's control unit has detected that the rear Power Take-Off (PTO) shaft is either not turning or is turning at a speed that is too slow when commanded to engage. The .01 Failure Mode Identifier (FMI) indicates that the sensor data is valid but falls below the normal operational range. This condition can be caused by incorrect operational settings, electrical faults, or mechanical problems within the PTO system.

• 6020
• 6120
• 6220
• 6320
• 6420
• 6420S
• 6230
• 6330
• 6430
• 6130
• 6930
• 8230T
• 8330T
• 8430T
• 9230
• 9330
• 9430
• 9530
• 9630

1. 1

   Review other active fault codes: If CCU 001883.00 (Rear PTO Overspeed) or CCU 001883.13 (Rear PTO Not Calibrated) are present, diagnose and resolve them first.

2. 2

   Verify tractor settings: Confirm the correct PTO shaft is installed for the implement, engine speed and throttle settings are appropriate, and the proper PTO engagement rate is selected on the CommandCenter display.

3. 3

   Power cycle the system: Turn the PTO switch off and on again, or cycle the tractor's main power to attempt a system reset.

4. 4

   Inspect electrical components (sensor cause): Visually inspect the wiring harness and connectors for the rear PTO speed sensor and the corresponding control unit (BCU/CCU). Look for visible damage, corrosion, loose connections, and check associated PTO fuses.

5. 5

   Monitor for PTO clutch slippage (mechanical cause): If there are signs of the PTO clutch slipping, allow the clutch to cool for a period before attempting to re-engage.

6. 6

   Confirm operator presence: Ensure the seat switch is functioning correctly, as the operator must be in the seat for the PTO to engage on many models.

1. 1

   Disconnect electrical cable

   Locate the rear PTO speed sensor on the chassis and carefully disconnect its electrical connector.

2. 2

   Remove the sensor

   Remove the hex socket screws securing the sensor to the housing and pull out the old sensor.

3. 3

   Install the new sensor

   Place a new O-ring on the new speed sensor before inserting it into the housing to ensure a proper seal.

4. 4

   Tighten the sensor

   Secure the new sensor with the mounting screws. Tighten them to the manufacturer's specified torque (e.g., 15 Nm for 6-series models).

5. 5

   Reconnect the cable

   Attach the electrical connector to the newly installed sensor.

6. 6

   Re-install guards

   If any protective guards were removed for access, reinstall them.

7. 7

   Clear fault codes

   Use the tractor's diagnostic system to clear the stored fault codes.

8. 8

   Test operation

   Start the tractor and engage the rear PTO to confirm that the fault has been rectified.