AIC 520542.03 – Vehicle CAN Bus Circuit Voltage High. John Deere AIC System Alert.

AIC 520542.03 (AIC )

Code: 520542.03



This diagnostic code, AIC 520542.03, occurs when the Armrest Interface Control Unit (AIC) detects that the voltage in the vehicle’s CAN Bus High (CAN+) circuit is abnormally high, suggesting a possible short to a 12V source. Such a condition often results from faulty wiring or a malfunction in connected devices, which can interrupt the normal operation of the CAN Bus and lead to erroneous or incomplete data transmissions across the system.


Due to the potential risk of damage from the high voltage, the control unit has disabled the affected function to prevent further complications and ensure system safety.


  • Inspect the CAN Bus High circuit for signs of damage or wear that could cause a short to a higher voltage source. Look specifically for frayed wires, loose connections, or degraded insulation.
  • Use a voltmeter to measure the voltage levels on the CAN+ line to confirm that they are exceeding normal operating parameters and to help identify the location of the fault.
  • Compare this issue with similar error codes from other control units, if available, to help pinpoint the source of the fault across the network.
  • Replace or repair any faulty wiring or components identified during the inspection. Ensure that all connections are secure and meet the system’s specifications.
  • After corrective actions are taken, reset the system and perform a comprehensive test to ensure that the CAN Bus is functioning correctly and the voltage levels have returned to normal.


Maintaining proper voltage levels in the CAN Bus system is crucial for the reliable operation of the vehicle’s electronic components. Regular checks and immediate correction of voltage irregularities are essential to prevent electrical failures and ensure the long-term health of the vehicle’s networked systems.