AIC 520543.04 – Vehicle CAN Bus Circuit Voltage Low. John Deere AIC System Alert.

AIC 20543.04 (AIC )

Code: 20543.04



This error code, AIC 520543.04, is triggered when the Armrest Interface Control Unit (AIC) detects that the voltage in the vehicle’s CAN Bus Low (CAN-) circuit is below the normal range. This typically indicates a short to ground. Such a fault can disrupt the integrity of data transmission across the vehicle’s CAN Bus system, leading to potential errors in communication between control units.


To prevent erroneous operations and potential damage to the system, the functionality of the affected circuit has been disabled.


  • Carefully inspect the CAN Bus Low circuit for any signs of shorts to ground, focusing on wiring, connectors, and related components for any damage or wear that could cause grounding.
  • Use a voltmeter to measure the voltage levels on the CAN- line to verify that they are indeed below expected values and help pinpoint the exact location of the short.
  • Compare this fault with similar error codes from other control units, if available, to assist in identifying a common point of failure that may affect multiple components.
  • Repair or replace any damaged or faulty wiring or components that are contributing to the low voltage condition. Ensure all repairs are done with high-quality materials to maintain system integrity.
  • Once repairs are completed, reset the system and conduct extensive testing to confirm that the CAN Bus is operating correctly, and that normal voltage levels have been restored.


Proper maintenance and monitoring of the CAN Bus network are crucial for ensuring reliable communication and operation of the vehicle’s electronic systems. Regular diagnostics and immediate attention to any disruptions in voltage levels help maintain system performance and prevent significant malfunctions.