2023-2024 Audi High-Voltage Battery Energy Content TSB

Audi has issued Technical Service Bulletin (TSB) 2074808/3 to provide dealerships with comprehensive information on determining the energy content of lithium-ion high-voltage batteries. This TSB is crucial for addressing customer concerns related to battery performance in 2023-2024 Audi models, specifically those equipped with an electric drive motor or high-voltage lithium-ion battery (fully electric and hybrid vehicles).

Symptoms

Owners of affected Audi vehicles may notice the following symptoms related to their high-voltage battery:

• Decreased Electrical Range: The vehicle's electric driving range may be noticeably shorter than expected.
• Increased Petrol Consumption (Hybrid Models): Hybrid vehicles might experience higher fuel consumption due to the high-voltage battery not contributing as effectively.
• Desire for Battery Status Information: Some owners may simply require reliable information about their vehicle's high-voltage battery status, for example, when considering selling the vehicle.

Dealership technicians investigating these complaints typically find that the customer's statement can be reproduced. Importantly, there are often no relevant active or static event memory entries logged in the control unit for hybrid battery management (diagnostic address 008C) indicating a fault with the high-voltage battery, making diagnosis challenging without specific procedures.

Diagnosis / Trigger Conditions

The underlying cause for these symptoms is the natural aging process of high-voltage batteries, which can lead to a reduction in energy content or energy density over time. This reduction is considered normal.

To accurately determine the Audi battery energy content, technicians use specific test plans available in the Guided Fault Finding system. These test plans are accessed via diagnostic address 008C under paths such as "Hybrid Battery Energy Management," "Battery management, functions," and "Determining remaining energy content of the high-voltage battery."

There are three primary test plans:

• Battery Health Status (BHS): Provides a general indication without a precise numerical percentage.
• Battery Health Certificate (BHC): Offers a numerical value in percentage with a tighter measurement tolerance.
• Battery Health Quick Test (BHQ): Also provides a numerical value in percentage, similar to BHC but with different application scenarios.

For warranty-related checks, the BHS and BHC tests are primarily used. If the BHS test indicates a battery capacity of 70% or above (marked as "OK"), no fault is considered present. If a long measurement is recommended, the BHC test is performed to get a precise percentage. If the capacity is below 70%, further warranty conditions must be checked.

Repair Procedure Summary

The TSB outlines specific procedures for checking the Audi battery energy content, depending on whether the check is performed under warranty or at the customer's request.

For Warranty Claims:

1. Initial Check: Technicians first perform the Battery Health Status (BHS) test plan using Guided Fault Finding.
2. Capacity Assessment: If the BHS test shows a battery capacity of 70% or above, the test concludes, as this is not considered a fault under warranty.
3. Detailed Measurement (if needed): If Guided Fault Finding recommends a long measurement, the Battery Health Certificate (BHC) test plan is then performed. This test provides a numerical percentage value for the battery capacity.
4. Warranty Conditions: If the BHC test reveals a battery capacity below 70%, technicians must consult the vehicle's specific warranty conditions to determine coverage. Contacting the importer before any high-voltage battery replacement is required.

For Customer-Requested Checks:

If a customer requests a battery energy content check for reasons such as selling the vehicle, technicians can use either the Battery Health Quick Test (BHQ) or the Battery Health Certificate (BHC) test plans. It is important to note that these customer-requested checks are generally not billable to the manufacturer under warranty.

Preconditioning the High-Voltage Battery:

To improve the accuracy of measurements and potentially reduce the time the vehicle spends in the workshop, preconditioning the high-voltage battery is recommended. This can lead to a more precise measurement tolerance of +/- 5 percentage points, compared to +/- 10 percentage points without preconditioning.

Owner Action

If you are experiencing decreased electrical range, increased petrol consumption in your hybrid Audi, or simply wish to know your Audi battery energy content, it is recommended to schedule an appointment with an authorized Audi dealership. They will be able to perform the necessary diagnostic tests using the procedures outlined in TSB 2074808/3.

If your vehicle is still under warranty and a justified customer complaint is established, the diagnostic work for the Battery Health Status (BHS) and Battery Health Certificate (BHC) tests may be covered. However, if the check is performed solely at your request without a warranty-covered fault, it may not be billable to the manufacturer.

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Source: NHTSA ID 11027358