2024-2025 Audi Q5 e 12V Battery Discharge TSB 2074126/5

Audi has released Technical Service Bulletin (TSB) 2074126/5 to address a concern regarding 12V battery discharge in 2024-2025 Audi Q5 e quattro vehicles. This issue is primarily caused by bus wake-ups initiated by the high-voltage charging unit. While a permanent production solution is still under development, Audi has provided a temporary workaround for affected vehicles.

This TSB, identified as 2074126/5, is particularly relevant for owners experiencing unexpected battery drain. It outlines the symptoms, technical background, and a procedure to temporarily mitigate the problem until a software update becomes available.

Symptoms of 12V Battery Discharge

Owners or technicians may observe the following conditions related to the Audi Q5 e 12V battery discharge:

• "The 12V battery is defective during the PDI inspection according to ODIS new vehicle battery test plan."
• "12V battery discharged after a stationary period."

These symptoms indicate that the 12V battery is losing charge unexpectedly, impacting vehicle readiness and potentially leading to starting issues.

Technical Background

The root cause of this Audi Q5 e 12V battery discharge issue is a software problem within the High-voltage Battery Charger Control Module Gen3 Kostal. This control module, identified by diagnostic address 00C6, is inadvertently causing bus wake-ups that lead to the 12V battery being discharged. The affected Q5 PHEV models are associated with hardware part number 9Y0915681 A/B/C/D and software version 3310.

Audi confirms that a permanent solution, likely a software update, is currently under development and will be provided in a future bulletin. For MY24 Q8 e-tron vehicles experiencing similar issues, technicians should reference TSB 2077527.

Important Warnings for Owners

Audi has provided crucial guidance for owners and technicians regarding this condition:

• A permanent solution is anticipated to be available by the end of the first quarter of 2026, though this timeline is subject to change. At present, no permanent repairs are necessary.
• "Do not replace any components for this condition since this will not resolve the customer's concern." This means that replacing the 12V battery or other related components will not fix the underlying software issue and should be avoided.
• It is important to note that performing a terminal 30 reset will cause vehicle settings to be reset, and any temporary workaround procedures will need to be repeated.

Temporary Workaround for Drive System Restoration

To prevent the Audi Q5 e 12V battery discharge from reoccurring and to restore the vehicle's drive system, Audi recommends a short-term procedure involving the infotainment system. This procedure should be performed as needed:

1. With the ignition on, navigate to the infotainment screen and select the "VEHICLE" tile. This tile is typically represented by a car icon, as shown in Figure 1 of the original bulletin.
2. Next, select the "Air conditioning" tile from the available options. This tile is usually found within the "VEHICLE" menu, as illustrated in Figure 2.
3. Proceed to select "Auxiliary air conditioning." This option is typically listed under the main "Air conditioning" menu, as depicted in Figure 3.
4. Within the "Auxiliary air conditioning" settings, select a timer option and then turn it on.
5. Immediately after turning the timer on, turn it off again. Figure 5 in the bulletin shows an example of a deactivated A/C timer.
6. Finally, return to the main menu of the infotainment system.

This sequence of actions is designed to temporarily resolve the bus wake-up issue.

Warranty Information

For vehicles experiencing the Audi Q5 e 12V battery discharge issue, warranty claims are handled under specific guidelines:

• Claim Type: If the vehicle is outside of its warranty period, this Technical Service Bulletin is for informational purposes only.
• Service Number: 9352
• Damage Code: 0039
• Labor Operations:
  • Set high-voltage charging unit: 9352 1599 (10 Time Units)
  • GFF / Guided Functions: 0150 0060 (Time stated on the diagnostic protocol)
  • GFF / Guided Functions: 0150 0010 (See SRT with associated operations)
• Claim Comment: As per TSB 2074126/3

All warranty claims must comply with the Audi Warranty Policies and Procedures Manual and are subject to review by Audi Warranty.

Revision History

This Technical Service Bulletin has undergone several revisions:

• Revision 5: Latest revision, purpose is "Revised Service (Updated expected ETA)".
• Revision 4 (09/15/2025): Purpose is "Revised Condition (Updated verbiage)" and "Revised Service (Updated expected ETA)".
• Revision 3 (06/31/2025): Purpose is "Revised Service (Updated expected ETA)".

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Source: NHTSA ID: 11029379