CAB 523841.03 – Secondary Brake Sensor Voltage High

CAB 523841.03 (CAB )

Code: 523841.03



The error code CAB 523841.03 is recorded when the CAB control unit detects that the voltage from the secondary hand brake lever position sensor is higher than expected. This overvoltage could be indicative of an electrical anomaly such as faulty wiring, a malfunctioning sensor, or issues with the vehicle’s voltage regulator. This condition is specific to European versions of the equipment and affects the secondary brake system, which is separate from the parking brake system.


Despite the high voltage reading, the control unit does not initiate any corrective action automatically. It relies on further diagnostic checks and manual interventions to address the issue.


  • Inspect Sensor and Wiring: Begin by examining the secondary hand brake lever position sensor and its associated wiring for any signs of damage, corrosion, or loose connections that might be causing the high voltage.
  • Measure Sensor Voltage: Use a multimeter to measure the voltage output at the sensor. Compare this with the normal operating range specified in the service manual to verify the discrepancy.
  • Check Voltage Regulators: Investigate all related voltage regulators and electrical systems that supply power to the sensor. Any malfunctioning components should be repaired or replaced to ensure stable voltage supply.
  • Replace Faulty Sensor: If the sensor itself is found to be faulty after these checks, replace it to restore proper functionality.
  • Document and Monitor: After addressing the issue, document the repairs made and monitor the system to ensure the voltage levels remain within the acceptable range during operation.


Regular electrical system checks are crucial to detect and rectify voltage irregularities before they lead to more significant problems. Maintaining the secondary brake system’s electrical components in optimal condition is essential for reliable brake performance and overall vehicle safety.

Control Units: John Deere

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