2021 Audi A4, A5, Q7 Front End Noise TSB

Owners of 2021 Audi A4, A5, and Q7 vehicles may experience various noises emanating from the front end or dash panel while the vehicle is in motion. This Technical Service Bulletin (TSB) 40 20 07 2047920/4 provides guidance for diagnosing and resolving these issues, specifically pointing to the front axle wheel bearings as a common source.

Symptoms

Customers typically report a range of auditory disturbances, including a "buzzing, booming, humming, whistling or a similar noise from the front end." These noises might also be perceived in the steering area or from behind the dash panel. Occasionally, owners may suspect these sounds are related to tire rolling noises, which can make diagnosis challenging. Workshop findings confirm that these noises are reproducible during a test drive.

Technical Background

The underlying cause for the 2021 Audi A5 front end noise, and similar issues in other affected models, is identified as mechanical damage to the wheel bearing of the front axle. The design of the vehicle allows these wheel bearing noises to transmit through the steering system into the vehicle's interior.

Diagnosis

Due to the close proximity and similar characteristics, distinguishing wheel bearing noise from tire rolling noise can be difficult. Technicians are advised to follow a series of diagnostic steps to accurately pinpoint the source of the 2021 Audi A5 front end noise:

• Observe if the noise frequency increases as vehicle speed rises or if the sound gets higher.
• Determine if the noise becomes louder when steering.
• Check if the noise persists when slowing down.
• Assess if the noise is amplified on the steering wheel or airbag area.
• Feel for vibrations on the unpressed coil spring when the wheel is turning.
• If wheel bearings are swapped, check if the noise moves with a particular bearing.

Audi recommends using acoustic testers to precisely locate the noise source. It is important to note that a noise perceived on the left side of the vehicle could originate from the right wheel bearing. Technicians are explicitly advised not to replace front wheel bearings in pairs unless both are confirmed faulty. If the noise cannot be traced to a wheel bearing, further analysis of other components is required.

Repair Procedure Summary

The repair for the 2021 Audi A5 front end noise involves replacing the affected front wheel bearing(s). The procedure varies slightly depending on whether one or both bearings need replacement, and specific labor operation codes are provided for warranty claims. For models such as the A4, A5, A6, and A7, replacing one front wheel bearing involves labor operation 4067 1900 (remove and install front hub with bearing) and 4057 5550 (replace front wheel bearing). If both front wheel bearings are replaced, labor operation 4067 2000 (remove and install 2 front hubs with bearings) is used.

For the Q7, replacing one front wheel bearing also uses labor operations 4067 1900 and 4057 5500. If both Q7 front wheel bearings are replaced, labor operations 4067 2000 and 4057 5600 (replace 2 front wheel bearings) are applicable. Diagnostic time includes a 10-time unit (TU) road test prior to the service procedure (0121 0002) and another 10 TU road test after the service procedure (0121 0004).

Required Parts and Tools

For the repair, technicians will need new wheel bearings (up to two, as needed). All specific part numbers for wheel bearings, fasteners, bolts, nuts, and screws should be referenced in ETKA and ELSA for the latest information and correct specifications.

Important Warnings

This Technical Service Bulletin is informational only if the vehicle is outside of its warranty period. Warranty claims must adhere to the Audi Warranty Policies and Procedures Manual, and are subject to review or audit by Audi Warranty. The TSB 40 20 07 2047920/4 supersedes previous bulletin Group 40 number 20-04 dated May 12, 2020.

NHTSA ID: 10175955