2021 Audi A4/A5/A6/A7/Q7 Front End Noise TSB

2021 Audi A4/A5/A6/A7/Q7 Front End Noise TSB: Understanding the Issue

Owners of certain 2021 Audi A4, A5, A6, A7, and Q7 models may experience various noises emanating from the front end or dash panel of their vehicles. These sounds, described as "buzzing, booming, humming, or whistling," are often heard when the vehicle is in motion. Audi has issued Technical Service Bulletin (TSB) 40 20 04 2047920/3 to address these concerns, identifying mechanical damage to the front axle wheel bearing as the root cause. This TSB supersedes a previous bulletin, Group 40 number 18-78, dated March 2, 2018, with updated information for additional models and model years.

Symptoms of Front End Noise

If your 2021 Audi A4, A5, A6, A7, or Q7 is affected by this issue, you might notice one or more of the following symptoms:

• A "buzzing, booming, humming, whistling or a similar noise from the front end."
• Noises that can be heard from the "steering area" or "behind the dash panel."
• A suspicion that the noises are "tire rolling noises."

These noises are typically reproducible during a test drive by a qualified technician.

Diagnosis and Trigger Conditions

Diagnosing the exact source of the "Audi A6 front end noise" can be challenging, as noises from the wheel bearing can transmit through the steering system into the vehicle's interior, making them difficult to distinguish from tire rolling noises. Audi's TSB 40 20 04 2047920/3 provides specific questions and tips for technicians to pinpoint the issue:

• Does the noise frequency increase as the vehicle's speed increases, or does the sound get higher?
• Does the noise become louder when steering the vehicle?
• Is the noise still present when the vehicle is slowing down?
• Is the noise amplified on the steering wheel or in the airbag well?
• Can vibrations be felt on the unpressed coil spring when the wheel is turning?
• If wheel bearings are swapped, does the noise move with a particular bearing?

Technicians are advised to use acoustic testers to precisely locate the source of the noise. It's important to note that a noise perceived on one side of the vehicle could originate from the wheel bearing on the opposite side.

Repair Procedure Summary

The primary repair for the "Audi A6 front end noise" involves replacing the affected front wheel bearing(s). The TSB outlines specific labor operations depending on whether one or both front wheel bearings need replacement, and varies slightly for the Q7 model.

For A4, A5, A6, and A7 models:

• One front wheel bearing: This involves removing and installing the front hub with the bearing (labor operation 4067 1900) and replacing the front wheel bearing (labor operation 4057 5550).
• Both front wheel bearings: This procedure includes removing and installing both front hubs with bearings (labor operation 4067 2000) and replacing two front wheel bearings (labor operation 4057 5650).

For Q7 models:

• One front wheel bearing: Similar to other models, this involves removing and installing the front hub with the bearing (labor operation 4067 1900) and replacing the front wheel bearing (labor operation 4057 5500).
• Both front wheel bearings: This requires removing and installing both front hubs with bearings (labor operation 4067 2000) and replacing two front wheel bearings (labor operation 4057 5600).

A road test is required both before and after the service procedure to confirm the diagnosis and verify the repair.

Required Parts and Tools

To perform this repair, technicians will need:

• Wheel bearings: Up to two, as specified in ETKA (Audi's electronic parts catalog).
• Fasteners, Bolts, Nuts, and Screws: As needed per the repair manual, also specified in ETKA/ELSA.

Always consult with the Parts Department and/or ETKA for the latest information and parts bulletins.

Important Warnings

Audi explicitly states that "The front wheel bearings should not be replaced in pairs" unless both are confirmed to be faulty. This guidance helps ensure efficient and accurate repairs, preventing unnecessary parts replacement.

Warranty Information

Repairs performed under TSB 40 20 04 2047920/3 are covered under Audi's New Vehicle Limited Warranty for up to 48 months or 50,000 miles, whichever comes first. For Certified Pre-Owned (CPO) vehicles, coverage falls under G10, requiring owner verification. If your vehicle is outside of any applicable warranty, this Technical Service Bulletin serves as informational guidance only, and repair costs would be at the owner's expense. The specific Service Number for this issue is 4057, and the Damage Code is 0020. All warranty claims must adhere to the Audi Warranty Policies and Procedures Manual.

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Source: NHTSA ID: 10175369