2021-2022 Audi Brake Noise TSB 2034181/18

Owners of 2021-2022 Audi e-tron and other Audi models may experience various brake noises. Technical Service Bulletin (TSB) 2034181/18, issued by Audi, provides detailed information for technicians to diagnose and resolve these concerns, which customers often describe as an Audi e-tron brake noise.

Symptoms

If you hear a brake noise from your front or rear brakes, it could manifest as:

• "squeal"
• "squeak"
• "grinding"
• "groaning"
• "thumping"
• "creaking"

Important Warnings for Owners

Audi has issued specific warnings related to this TSB:

• Do not use this TSB if there is another brake noise TSB applicable to your vehicle's VIN. Always check for the most relevant bulletin.
• If your vehicle is outside of its warranty period, this Technical Service Bulletin is for informational purposes only, meaning any repairs may not be covered.

Technical Background: Why Brake Noise Occurs

Brake noise can stem from several common issues. Understanding these can help in proper diagnosis:

1. Wear Limit: Brake discs or pads are close to or below their wear limit.
2. Improper Embedding: New brake pads and/or discs were not properly embedded after installation.
3. Aftermarket Parts: Installation of non-OEM (aftermarket) pads or discs.
4. Debris: Small stones, grit, road salt, or sand lodged between the brake disc and brake pad.
5. Rust: Discs covered with rust, often occurring when the vehicle has not been driven for an extended period.
6. Grooved Discs: The brake discs have developed grooves.
7. Chemical Contamination: Chemical residue on the braking surface of the brake disc, typically from wheel or tire cleaner sprayed directly onto the disc.
8. Pad Marks: Brake pad material has transferred to the discs, especially after the vehicle has been parked for long periods in wet or snowy conditions.

Diagnosis and Repair Procedure Summary

Addressing an Audi e-tron brake noise involves a systematic approach:

1. Initial Brake Condition Check: Technicians first inspect the overall condition of the brakes to determine if the noise aligns with any of the common causes listed in the technical background section of this bulletin.
2. Locate the Noise: The exact location of the brake noise (e.g., left front, front axle, rear axle) is identified. An assistant may be needed to help pinpoint the sound's origin.
3. Record and Document: A sound or video recording of the noise is obtained, preferably using the Audi analysis app (as referenced in TSB 2051095: 46 Audi frequency analysis). Customers' recordings are also acceptable. A detailed questionnaire must be filled out.
4. Clean Brakes: Brake pads and discs are thoroughly cleaned.
5. Brake Bedding Procedure: Up to five ABS stops are performed from speeds above 50 mph. Between each stop, the vehicle is driven for more than one minute at speeds greater than 50 mph to allow brake components to cool.
6. Cool Down: The vehicle is allowed to sit for two hours to cool down completely.
7. Re-test Drive: The vehicle is test-driven again to confirm if the noise has been eliminated.
8. Technical Assistance: If the noise persists, a Technical Assistance Center (TAC) ticket is opened. This ticket must include the completed Brakes Acoustic Questionnaire, sound/video recordings, a frequency analysis screenshot, and photos of the affected brake discs and pads.

Required Tools or Parts

For specific brake system issues, the repair procedure may involve:

• Anti-seize paste G052560A2: Used to clean and lubricate guide pins in the caliper carrier for TRW brake systems.

Specific Brake System Frequencies and Repair Suggestions

Different brake systems and noise frequencies may indicate specific issues:

• Brake system ATE-TEVES (with PR codes: 1LF, 1LG, 1LL, 1ZK, 1LJ, 1LP):

  • 1.6 KHz from front brakes: Inspect the front pads.
  • 3.2 KHz/11 KHz from front brakes: Inspect both the front discs and pads.

• Brake system TRW (with PR codes: 1LA, 1LB, 1LD, 1LT, 1ZT, 1LJ):

  • 1.6 KHz to 1.7 KHz from front brakes: Inspect the front discs.
  • 3.2 KHz from front brakes: Inspect, and if necessary, clean and lubricate the guide pins in the caliper carrier using anti-seize paste G052560A2.
  • 7.8 KHz from front brakes: Inspect the front pads.

Warranty Information

This TSB outlines warranty claim procedures for eligible vehicles:

• Claim Type: 110 (up to 48 Months/50,000 Miles).
• Service Number: 4617
• Damage Code: 0020
• Labor Operations: Cleaning brake pads and discs (code 4617 8099, 70 TU), which includes road tests, audio file submission, and questionnaire completion.
• Diagnostic Time: No allowance for GFF, road test prior, or road test after the service procedure.
• Claim Comment: As per TSB #2034181/18.

Additional Information

This bulletin supersedes Technical Service Bulletin Group 46 number 19-08 dated March 18, 2019. Technicians may also need to refer to other related TSBs for a complete diagnosis:

• TSB 2022584, 46 Brake pulsation diagnostic guidelines.
• TSB 2051095, 46 Audi frequency analysis.

Source: NHTSA ID 10186994