RPT 000186.04 – Rear PTO Speed Sensor, Voltage Too Low

RPT 000186.04 (RPT 186.04)

Code: 000186.04

Shortcode: 186.04


This diagnostic trouble code, RPT 000186.04, is generated when the control software detects that the voltage at the signal input of the rear PTO speed sensor is too low. This indicates a short to ground in the circuit of the rear PTO speed sensor.


When this error is detected, the functionality of the rear PTO is significantly limited or entirely non-functional, affecting the operation of the connected implement.


Inspect Rear PTO Speed Sensor Circuit:

  • Check the wiring to the rear PTO speed sensor for signs of a short to ground.
  • Repair or replace any damaged wires or connectors.

Verify Sensor Connections:

  • Ensure all connections to the rear PTO speed sensor are secure and free from corrosion or damage.
  • Reconnect any loose wires and clean any corroded connectors.

Test Sensor and Voltage Levels:

  • Use diagnostic tools to test the rear PTO speed sensor and measure the voltage levels at the signal input.
  • Replace the sensor if it is found to be faulty.

Update Control Software:

  • Ensure that the control software is updated to the latest version.
  • Apply any available patches or updates that address voltage regulation issues.

Consult Technical Support:

  • If the problem persists, consult with technical support or the equipment manufacturer for further assistance.
  • Provide detailed error logs and voltage measurements to aid in troubleshooting.

Monitor PTO System Performance:

  • After addressing the issue, monitor the rear PTO system to ensure it operates correctly and the voltage levels are within the specified range.
  • Keep detailed records of any further voltage-related errors.


Low voltage at the rear PTO speed sensor can lead to significant performance issues in the PTO system. Regular inspections and maintenance of the PTO sensor and circuit are essential to prevent such issues.

Control Units: John Deere

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