2022-2024 Audi e-tron GT Brake Pedal Vibration TSB

Owners of 2022-2024 Audi e-tron GT and RS e-tron GT vehicles may experience a vibration or pulsation in the brake pedal, or a sensation that the brake response feels "different." This condition, which can occur during braking at low speeds, is addressed by Audi Technical Service Bulletin (TSB) 2068205/5. This bulletin, last revised on March 22, 2024, supersedes previous bulletin 23-23 dated April 18, 2023.

Symptoms

If you own a 2022-2024 Audi e-tron GT or RS e-tron GT, you might notice the following:

• "During braking at low speeds, a vibration/pulsation is felt at the brake pedal."
• "The brake response feels 'different'."

These symptoms indicate a potential issue with the brake system, leading to an Audi e-tron GT brake pedal vibration or an unusual feel.

Fault Codes / DTCs

When these symptoms are present, a workshop diagnosis may reveal a specific Diagnostic Trouble Code (DTC) stored in the ABS/ESC Control Module -J104- (address word 0003):

Diagnosis and Trigger Conditions

The TSB indicates that the complaint of Audi e-tron GT brake pedal vibration can be reproduced during testing. The technical background highlights several characteristics of the e-tron GT brake system that contribute to these sensations.

New vehicles or those with recently changed brake pads require a "bedding-in routine." This process, which can take up to 1000 miles depending on driving style, involves brief deactivations of the recuperation function. The TSB notes that the bedding-in routine may not yet be complete.

Additionally, the vehicle features a "Brake refresh" function, which applies braking energy to mechanical brakes after the vehicle has been stationary for an extended period (12+ hours) to preserve friction values. A "Stiffness adaptation routine" also occurs during regenerative braking, where the control units learn the brake system's stiffness. This routine involves the brake pedal moving approximately 1 inch without activating the brake lights and takes about 10 seconds. It occurs during every charging procedure, provided brakes are not hot and the steering wheel is not significantly turned.

Pedal travel may also feel longer when maneuvering due to a smaller brake master cylinder designed to improve modulation during parking. The vehicle's system also fully opens both brake circuits at speeds below 12 mph to reduce noise, vibrations, and improve comfort, leading to longer pedal travel. Furthermore, ceramic and tungsten carbide brakes may exhibit inferior friction in wet or cold conditions compared to cast iron brakes, which can also affect pedal feel when switching from electric to hydraulic braking.

Repair Procedure Summary

The resolution for the Audi e-tron GT brake pedal vibration and related symptoms involves checking and potentially updating the ABS software, along with ensuring proper brake system routines are completed.

1. Software Level Check: Technicians must check the ABS software level. If it is below version 190, they should review if the vehicle is included in Campaign 49A4 and proceed with the necessary software update.
2. Bedding-in Routine: Ensure the brake bedding-in routine is fully completed. Once completed, the DTC P05FF00 should automatically clear from the ABS/ESC control unit. Further details on this are available in TSB 2063679.
3. Customer Information: It is crucial for technicians to inform customers about the normal characteristics of the e-tron GT's brake system, including the "Brake refresh" and "Stiffness adaptation routine" functions, and that pedal travel may be longer during maneuvering. Owners should also be made aware of the potential for different friction values with ceramic/tungsten carbide brakes in certain weather conditions. The owner's manual can be referenced for this information.
4. Final Software Update: If, after all these steps, the brake pedal travel still feels unsuitable, and the ABS control unit software is below version 190, an update should be performed.

Warranty Information

Warranty claims for this issue are generally covered for up to 48 months or 50,000 miles, whichever comes first, under claim type 110. If the vehicle is outside of warranty, this Technical Service Bulletin is for informational purposes only. The service number for this bulletin is 4708, with a damage code of 0011. Specific labor operations include bleeding the brake system (4701 0750), diagnostic time (GFF 0150 0000), and road tests before (0121 0002) and after (0121 0004) the service procedure.

What Owners Should Know

It is important for owners to understand that some perceived differences in brake feel, such as longer pedal travel during maneuvering, are inherent characteristics of the Audi e-tron GT's advanced brake system. The "Brake refresh" and "Stiffness adaptation routine" are normal functions designed to optimize brake performance and feel. However, if you experience persistent Audi e-tron GT brake pedal vibration or a significantly different brake response, especially if accompanied by a warning light, it is recommended to have your vehicle inspected by an authorized Audi service center.

NHTSA ID: 10252098