BRC 000158.04 – Low Switched Supply Voltage in Brake Control Unit. John Deere System Advisory.

BRC 000158.04 (BRC 158.04)

Code: 000158.04

Shortcode: 158.04


The error code BRC 000158.04, related to the Brake Control Unit (BRC), signifies that the switched supply voltage has dropped below the threshold of 9.0 volts. This low voltage situation could affect the proper functioning of the brake control system, potentially impacting the vehicle’s braking capabilities.


The system’s response to this low voltage condition is to activate an indicator or alarm. This is a cautionary measure to inform the operator of the voltage issue without affecting the brake functionality immediately.


  • Check Electrical Connections: Ensure that all connections to the Brake Control Unit are secure and free from corrosion or damage, which could cause voltage drops.
  • Inspect the Power Supply System: Examine the vehicle’s battery and alternator to confirm they are functioning correctly and providing adequate voltage to the BRC.
  • Voltage Testing: Use a multimeter to test the voltage supply to the BRC to verify if it consistently remains below the 9.0 volts threshold.
  • Resolve Electrical Issues: Address any identified issues within the electrical system that could be causing the low voltage, such as worn wires or faulty connections.
  • System Reset and Re-test: After making repairs, reset the Brake Control Unit and perform a comprehensive test to ensure the voltage level is maintained above 9.0 volts during operation.


Maintaining the correct voltage supply is essential for the reliable operation of the Brake Control Unit. Regular checks and maintenance of the vehicle’s electrical system can prevent issues related to low voltage supply, thus ensuring the safety and effectiveness of the braking system.