Description
Used 48V alternator control board specifically designed for Audi A8/S8 (D5) mild hybrid models, with the original equipment number 4N1903028.
Common Fault Symptoms
48V battery fails to charge normally
Part Number Details
Manufacturer Part Number: —
Vehicle OE Part Number: 4N1903028
Compatible Part Numbers: 4N0903028 (all variants)
Product Condition & Notes
Hardware Status: Refurbished and fully functional, pre-tested before shipment
Post-Installation Requirement: Coding via ODIS diagnostic system is mandatory after mounting the board on the vehicle
Complete Installation & Activation Procedure
Fully charge the vehicle's 12V auxiliary battery
Turn on the ignition switch; the 48V battery should reach a 25% charge level
Perform coding for the new alternator control board using ODIS
Access the BMS (Battery Management System) to check real-time data:
If the 48V battery charge is below 10%, it requires external charging
If the charge drops below 5%, the battery will be locked by software; unlock it by entering pairing mode and disabling protection, then activate the battery
Enter the diagnostic interface for Module 21 (Battery BMS), select access authorization, and input the login code 20103 to activate the system; the 48V high-voltage system will then go online
If the 48V battery still cannot charge: Disconnect the 12V battery and use the diagnostic tool to reset all related control modules
This part number 4N0903028P is applicable to a range of Audi models across different years and chassis types, specifically including the Audi A6 (C8, 2018–2023), Audi S6 (C8, 2019–2023), Audi RS6 (C8, 2019–2023), Audi A7 (4K8, 2018–2023), Audi S7 (4K8, 2019–2023), Audi RS7 (4K8, 2019–2023), Audi A8 (D5, 2017–2023), Audi S8 (D5, 2020–2023) and Audi Q8 (2019–2023).