BCU 000186.02 – Rear PTO Speed Sensor Open Circuit. John Deere System Advisory.

BCU 000186.02 (BCU 186.02)

Code: 000186.02

Shortcode: 186.02


Error code BCU 000186.02 is triggered when the Basic Control Unit (BCU) of a John Deere vehicle detects an open circuit in the rear Power Take-Off (PTO) speed sensor during a sensor circuit check. This fault indicates a discontinuity or break in the circuit that prevents the sensor from transmitting speed data back to the BCU, which could adversely affect PTO operations and overall machinery performance.


The detection of an open circuit typically results in the deactivation of the PTO function or an alert to the operator, as the system cannot reliably control PTO operations without accurate speed data.


  • Inspect Sensor and Wiring: Examine the rear PTO speed sensor and associated wiring for any signs of damage, wear, or disconnections that might cause an open circuit. Pay particular attention to connector pins and contact points.
  • Check for Corrosion and Damage: Look for corrosion, cuts, or abrasions on the wires that could lead to an open circuit. Repair or replace damaged wiring as needed to restore continuity.
  • Test Sensor Connectivity: Use a multimeter to test the continuity of the sensor circuit. This will help identify if the open circuit is at the sensor itself or within the wiring.
  • Replace Faulty Sensor: If the sensor itself is damaged or malfunctioning, replace it to ensure it can accurately measure and report PTO speed.
  • Reset the BCU and Re-test: After making the necessary repairs, reset the BCU to clear the fault code and conduct a test to verify that the sensor and circuit are functioning correctly.


Regular maintenance and checks of the PTO system and its sensors are critical for ensuring reliable operation. Addressing issues like open circuits promptly can prevent operational disruptions and maintain the effectiveness of the PTO and related systems. Ensuring these components are correctly functioning helps maintain the overall productivity and efficiency of your John Deere equipment.