2024 Audi Q5 12V Battery Discharged by Bus Wake-Up TSB

Audi has released Technical Service Bulletin (TSB) 2074126/1 to address a concern where the 12V battery in certain 2024 Audi Q5, Q5 e, and SQ5 models may discharge unexpectedly. This issue, described as a "12V battery discharged by bus wake-up," is attributed to a software problem within the High-voltage Battery Charger Control Module.

This bulletin provides a temporary workaround for affected vehicles while Audi develops a permanent software update. Owners experiencing the Audi Q5 12V battery discharged issue should be aware of the recommended steps.

Symptoms

Owners of affected vehicles may notice one of the following conditions:

• "Battery failure at PDI" according to the ODIS new vehicle battery test plan during pre-delivery inspection.
• The 12V battery is discharged after the vehicle has been stationary for some time.

Technical Background

The root cause of the Audi Q5 12V battery discharged problem is identified as a software issue within the High-voltage Battery Charger Control Module, specifically at diagnostic address 00C6. This module, manufactured by Gen3 Kostal, is inadvertently waking up the vehicle's electrical bus, leading to parasitic drain and battery discharge.

Important Warnings for Owners

Audi has provided specific guidance regarding this condition:

• "Explain to the customer that a solution is expected to be available by the end of the 1st quarter of 2025 (subject to change) and that no repairs are necessary at this point. Do not replace any components for this condition since this will not resolve the customer's concern."
• "A terminal 30 reset causes the settings to be reset and the procedure must be repeated."
• "If the vehicle is outside of any warranty, this Technical Service Bulletin is informational only."

This means that replacing the battery or other components will not fix the underlying software issue. A permanent fix is still under development.

Temporary Workaround Procedure

To prevent the 12V battery from discharging while a permanent solution is being developed, Audi recommends a specific procedure involving the MMI infotainment system. The steps vary slightly between Q5 PHEV and Q8 e-tron models.

For Q5 PHEV Models

1. With the ignition on, select the “VEHICLE" tile on the MMI screen.
2. Select the “Air conditioning" tile.
3. Choose “Auxiliary air conditioning."
4. Select a timer and turn it on.
5. Immediately turn the timer off.
6. Return to the main menu.

For Q8 e-tron Models

1. Select the charging symbol in the lower MMI screen.
2. Select the clock symbol, which will take you to the charging menu.
3. Activate a charging timer. You may see messages like "The vehicle cannot be charged due to the power supply." or "Charging not in progress."
4. Select the clock symbol again to activate the timer.
5. Deactivate the time selected in the previous step.
6. Return to the main menu.

This procedure temporarily addresses the software glitch that causes the Audi Q5 12V battery discharged problem.

Affected Components and Software

The High-voltage Battery Charger Control Module (address word 00C6) is implicated in this issue. The specific hardware part numbers and software versions found in these modules are:

• For Q5 PHEV:
  • Hardware Part Number: 9Y0915681 A/B/C/D
  • Software Version: 3310
• For Q8 e-tron:
  • Hardware Part Number: 9J1915684 B/N
  • Software Version: 3112 / 3115

Warranty Information

This Technical Service Bulletin (TSB 2074126/1) outlines the warranty claim procedures for dealers.

• Claim Type: 110 (Up to 48 Months/50,000 Miles) or G10 for CPO Covered Vehicles.
• Service Number: 9352
• Damage Code: 0039
• Labor Operations:
  • Setting high-voltage charging unit: 9352 1599 (10 Time Units)
  • Diagnostic Time (GFF / Guided Functions): 0150 0060 (Max 10 TU) and 0150 0010 (See SRT with associated operations)
  • Test drives before and after the service procedure are covered with no allowance (0 TU).
• Claim Comment: As per TSB 2074126/1.

Production Solution Status

Audi states that a permanent solution for the software issue causing the Audi Q5 12V battery discharged condition is currently under development. The company expects to provide an update to this bulletin when more information becomes available, with a solution anticipated by the end of the first quarter of 2025.

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Source: NHTSA ID: 11003000