Audi MHEV Fault Codes P0A7D00, P0B2900 & P065C00 Diagnose & Repair Service

VAG Bolton are starting to hear from an increasing number of Audi MHEV (Mild Hybrid Electric Vehicles) owners whose vehicles are affected by 3 particular faults.

The following mild hybrid Audi vehicles (model years 2017-2024) are affected:

Audi A6/A7 (3.0L TDI 48 Volt MHEV)
Audi Q7 (3.0L TDI 48 Volt MHEV)
Audi S7 (3.0L TDI 48 Volt MHEV)

Audi POA7D00 fault in detail (Battery State of Charge Low)

Your MHEV vehicle may experience 1 or more of the following issues:

Vehicle will not charge
Vehicle may not start
Unexpected engine/hybrid system shut down

The 48V battery is in low voltage protection state and will not accept a charge. Error code DTC POA7D00 – Hybrid/EV Battery Pack State of Charge Low.

When the battery (48V) falls below a pre-determined state of charge the protection relays inside the battery open to ensure the internal battery cells remain above the safe minimum voltage limit.

This can lead to the protection relays not closing until the appropriate adaption channel is set within the battery.

This fault could indicate problems with other components including the vehicles alternator or battery system.

Using genuine Audi equipment and software VAG Bolton offer a professional diagnosis service to identify what the cause is.

Audi P0B2900 fault in detail (Hybrid/EV Battery ‘B’ Voltage Low)

Your MHEV vehicle may experience the following issues:

Vehicle will not charge
Warning lights on dashboard
Vehicle may not start at all
Unexpected engine/hybrid system shut down
Stop/start system may stop working
Sluggish/limp home performance

This fault code P0B2900 means that the vehicles hybrid battery ‘B’ voltage is low. This affects Audi group vehicles which feature the 48 Volt mild-hybrid (MHEV) battery system, typically fitted to larger 3.0 TDI equipped vehicles such as the A6/A7/Q7 ranges.

The battery ‘B’ designation refers to a specific section or component of the battery system indicating a voltage drop in 1 or more modules or group of battery cells.

This fault could indicate problems with the vehicles components including the alternator, battery system, battery control module or potentially a separate wiring issue.

Using genuine Audi equipment and software VAG Bolton offer a professional diagnosis service to identify what the problem is.

Audi P065C00 fault in detail (Generator 'A' Mechanical Performance)

Your 48V MHEV vehicle may experience the following issues:

Warning lights/message on dashboard (“Major Electrical System Failure” message)
General electric faults/no dashboard displays
Stop/start system may stop working

Again, this fault code relates to the above Audi range (A7/A7/S7/A8/Q7/Q8) which feature the 48V mild-hybrid system. This fault is connected to the integrated starter generator (ISG) which fails to perform according to manufacturer specifications.

This faulty ISG issue seem to particularly effect model years 2019-2021.

About VAG Bolton

VAG Bolton is family run business established in 1992. We specialise in the servicing and maintenance of VAG Group Motors, such as Volkswagen, Audi, Porsche, SEAT and Skoda. We are conveniently based in Kearsley, Bolton which is close to the M60, M61, M62 and M66 motorways.

VAG engineers will first diagnose the problem before rectifying the issue. Please contact us to discuss repairs to vehicles featuring DSG geaboxes, experiencing the park position sensor issues (Error Code P0A7D00 & P0B2900).