RPT 001890.03 – PTO Shaft Spline Identifier Switch, Voltage Too High

RPT 001890.03 (RPT 1890.03)

Code: 001890.03

Shortcode: 1890.03


This diagnostic trouble code, RPT 001890.03, is generated when the RPT control software registers a voltage in excess of 85% of the system voltage at the PTO shaft spline identifier switch. Such high voltage levels indicate a malfunction in the PTO shaft spline identifier switch or associated circuitry.


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 PTO Shaft Spline Identifier Switch:

  • Check the PTO shaft spline identifier switch for any visible damage or disconnections.
  • Ensure the switch is securely mounted and connected properly.

Check Wiring and Connections:

  • Inspect the wiring and connections related to the PTO shaft spline identifier switch for signs of damage, corrosion, or loose connections.
  • Repair or replace any damaged components.

Test Voltage Levels:

  • Use diagnostic tools to measure the voltage levels at the PTO shaft spline identifier switch.
  • Ensure the voltage is within the acceptable range (15%-85% of system voltage).

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 within the specified voltage range.
  • Keep detailed records of any further voltage-related errors.


High voltage at the PTO shaft spline identifier switch can indicate serious electrical issues that need prompt attention to prevent further damage. Regular inspections and maintenance of the PTO system and its electrical components can help prevent such problems.

Control Units: John Deere

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