CAB 000091.04 – Low Voltage Detection in Foot Throttle Sensor Circuit

CAB 000091.04 (CAB 91.04)

Code: 000091.04

Shortcode: 91.04


The fault code CAB 000091.04 occurs when the CAB control unit detects an input voltage lower than expected at the foot throttle sensor. This low voltage condition can compromise the sensor’s ability to accurately relay throttle position, affecting engine speed control and overall vehicle performance.


As a protective measure, the system automatically limits the maximum throttle operation to half throttle. This restriction helps prevent potential engine stalling and ensures safer operation under compromised sensor conditions.


  • Examine Sensor and Electrical Connections: Start with a thorough inspection of the foot throttle sensor and its connections. Check for any signs of wear, damage, or corrosion that could be causing voltage drops.
  • Test Voltage Levels: Use a multimeter to measure the voltage at the sensor input. Verify that it matches the specifications in the service manual. Low readings can indicate issues such as poor grounding, inadequate wire gauge, or a failing power supply.
  • Ensure Ground Integrity: Verify that all grounding points in the sensor circuit are secure and free of corrosion. Poor grounding can frequently result in low voltage issues.
  • Replace or Repair Sensor if Necessary: If diagnostics suggest the sensor itself is faulty, replace it or repair any damaged components to restore proper function.
  • Reassess System After Repair: After any repairs are made, recalibrate the sensor and perform a comprehensive test of the throttle system to ensure it responds accurately across the entire operating range. Continue to monitor the system to confirm the resolution of the issue.


Maintaining the electrical integrity of the throttle sensor system is critical for optimal vehicle performance. Regularly scheduled diagnostics and preventive maintenance can prevent issues related to voltage anomalies, enhancing the longevity and reliability of the equipment.

Control Units: John Deere

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