PTH 000091.04 – Throttle Sensor Input Voltage Below Normal, or Shorted to Low Source

PTH 000091.04 (PTH 91.04)

Code: 000091.04

Shortcode: 91.04


This fault code indicates that the hand throttle sensor input voltage is below normal levels or shorted to a low power source, which could be due to a short to ground or an open circuit. This can be caused by wiring issues or a malfunctioning throttle sensor.


When this error is detected, the equipment may experience issues with throttle control, leading to poor engine performance or unstable speed regulation. The system might limit throttle functionality to prevent damage.


Inspect Hand Throttle (P03) Without ECU:

  • Check the hand throttle for proper operation.
  • Ensure the throttle is not damaged and is correctly positioned.

Verify Wiring and Connections:

  • Inspect the wiring harness connected to the throttle sensor for any signs of damage, wear, or loose connections.
  • Repair or replace any damaged wiring.

Test Power Train Hydrostatic Control Unit (PTH):

  • Perform diagnostic tests on the control unit to identify any faults.
  • Verify all electrical connections to the control unit are secure and corrosion-free.

Update Control Software:

  • Ensure the control unit software is current with the latest updates and calibrations.

Consult Technical Support:

  • If the fault persists, contact technical support for further diagnostics and possible sensor replacement.

Monitor System Performance:

  • After addressing the issue, closely monitor the throttle system to ensure normal operation and that the fault does not reappear.


Regular inspection and maintenance of the throttle sensor and associated wiring can prevent this fault. Environmental conditions such as extreme temperatures or exposure to moisture can also impact sensor performance, so these factors should be considered during troubleshooting.

Control Units: John Deere

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