2017-2022 Audi A4/A5 Creaking Noise from Floor Area TSB

Symptoms

Owners of certain 2017-2022 Audi A4 and A5 vehicles may experience a distinct Audi A4 A5 creaking noise emanating from the floor area. This "creaking type noise" is most noticeable and can be generated during strong braking or steering maneuvers, particularly when the vehicle body is twisted. Workshop findings indicate that the source of this noise specifically radiates from the footwell area to the region under the seat.

Technical Background

The root cause of this Audi A4 A5 creaking noise has been identified. During cornering or hard braking maneuvers, the longitudinal member reinforcement plate 'P' located over the threaded console 'T' can make contact at point 'U'. This contact generates the audible creaking. Audi has since implemented an improved construction in the longitudinal member assembly in production to address this issue.

Diagnosis

Diagnosing the creaking noise involves a systematic approach to confirm its origin and ensure the repair outlined in Technical Service Bulletin 50 21 06 2062633/1 will be effective.

1. Test Drive and Noise Duplication: A test drive should be performed, preferably with the customer, to clearly identify the specific conditions under which the creaking noise occurs. It's also crucial to determine from which side of the vehicle the noise originates. If the noise is successfully duplicated on the test drive, and confirmed to be from the longitudinal member, the repair described in TSB 50 21 06 2062633/1 can be effective.
2. Initial Subframe Bolt Loosening: Begin the diagnostic process by loosening the front-most bolt on the subframe mounting, as illustrated in Figure 2 of the TSB. The bolt only needs to be loosened by several turns, not completely removed. In many cases, an audible 'cracking' noise may be heard during the loosening and tightening of this subframe bolt (Figure 3).
3. Warming for Cold Conditions: If the noise is difficult to reproduce when the vehicle is cold, the longitudinal member and body in the area of the rear transverse link bolted connection should be warmed. Use a hot air blower set to an outlet temperature of approximately 550°C (1022°F) (Figure 4). Warm the surface to approximately 65°C (149°F) (Figure 5).
4. Cooling and Re-testing: Allow the warmed surface temperature to cool to approximately 30°C (86°F) (Figure 6), then test drive the vehicle again. Merely lowering the vehicle from the hoist after this warming process can sometimes immediately elicit the noise symptom.

Important Warnings

• If there is no change or elimination of the noise after this diagnostic step, the repair outlined in TSB 50 21 06 2062633/1 will not be effective, and further diagnosis outside the scope of this procedure will be necessary. However, if the noise characteristics change or the noise is eliminated, proceed with the repair.
• If the vehicle is outside any warranty, this Technical Service Bulletin is informational only.

Repair Procedure Summary

Once the Audi A4 A5 creaking noise is confirmed to originate from the longitudinal member, the repair involves modifying the contact point and applying protective wax. The procedure is detailed and requires specific steps:

1. Underbody Trim Removal: To gain necessary access, remove the front middle underbody trim 'B', front underbody trim 'C', and the underbody trim 'D', as shown in Figure 7 of the TSB.
2. Longitudinal Member Access: Unscrew the four sheet nut fasteners 'F' that secure the heat shield to its studs. Gently bend the heat shield slightly away from the longitudinal member (Figure 8). Then, remove grommet 'E' and grommet 'H' from the longitudinal member (Figure 9).
3. Subframe Bolt Replacement: Since bolt 'G' was loosened during the diagnosis process, it must be replaced. Use the installation and tightening procedure specified in ElsaPro for this replacement.
4. Impact Protector Removal: Remove the impact protector 'K'. Pry out clip 'I' from the impact protector and then remove it from the longitudinal member (Figures 10 and 11).
5. Special Tool Fabrication: An improvised tool is essential for this repair. Obtain a steel rod with a 10mm diameter and 50cm length. Grind the tip of one end into a chisel shape, ensuring the grind length is 15mm +/-3mm on each side (Figure 14). Mount one end of the rod into a vice, 11cm deep, with the chisel shape parallel to the ground (Figure 15). Bend the steel bar at the 11cm apex until a distance of 43mm +/- 3mm is created between the axis of the longer end of the rod and the axis of the shorter end at its tip (Figure 17). Verify this distance (Figure 18).
6. Tool Insertion and Engagement: Insert the chisel end of the fabricated steel rod 'A' into the body opening 'L' (the original location of grommet 'E') in the longitudinal member (Figure 19). Feed the steel rod 'A' through hole 'M' in the reinforcement plate (Figure 20). The chisel end must be fed far enough to engage the front reinforcement plate 'P' at point 'O', lodging it into the gap between reinforcement plate 'P' and the wall of the longitudinal member 'R' (Figure 21). The tool's bend angle and chisel point orientation, if correctly formed, will guide it to the appropriate contact point (Figure 22). Ensure the chisel end is properly engaged with the reinforcement plate, consistent with the space formed by the longitudinal member support (Figure 23). Figure 24 illustrates an incorrect engagement of the chisel end.
7. Creating the Gap: Using a marker, mark the point where the steel rod contacts the longitudinal member, then make a second mark 10mm – 15mm rearward on the steel rod (Figure 25). With a hammer, drive the steel rod forward by 10mm (Figure 26). This action creates an approximate 3mm gap between the reinforcement plate 'P' and the longitudinal member 'R', effectively separating this contact point and eliminating the source of the Audi A4 A5 creaking noise (Figure 27).
8. Cavity Wax Application: All areas that were contacted or struck during this process may have had their corrosion protective layer compromised. Therefore, thoroughly coat all these areas with cavity wax (Figure 28). The cavity wax can be applied through various openings, including hole 'S', to access the separation point within the longitudinal member (Figure 29).
9. Reassembly and Final Test: Reassemble the vehicle according to the repair manual. Perform a final test drive to confirm the complete elimination of the noise by replicating the customer's reported driving conditions. Ensure the customer is satisfied with the repair by driving with them during vehicle handover.

Required Tools and Parts

To perform the repair outlined in TSB 50 21 06 2062633/1, specific materials and tools are required:

• Fasteners, Bolts, Nuts, and Screws: As needed per the repair manual. Technicians should consult ETKA for the latest information on specific part numbers.
• Cavity Wax:
  • D 330 KD1 A2
  • D 330 KD2 A1
  • Alternatively, 08852 3M™ Cavity Wax (available from Top Service Supplies and Touch Up Paint estore)
• Special Improvised Tool: A steel rod, 10mm in diameter and 50cm long, with one end ground to a chisel shape (15mm +/-3mm grind length) and bent 11cm from the chisel end to create a 43mm +/- 3mm offset between the axis of the longer end and the axis of the shorter end at its tip.

Warranty Information

This Technical Service Bulletin (TSB) specifies the following warranty claim details for addressing the Audi A4 A5 creaking noise:

• Claim Type: 110, applicable for vehicles up to 48 months or 50,000 miles.
• Service Number: 5079
• Damage Code: 0010
• Labor Operations:
  • Check longitudinal member: 5079 9999 (40 Technical Units - TU)
  • Modify longitudinal member: 5080 9999 (100 TU)
  • Alternatively, for both sides:
    • Check longitudinal members – Both sides: 5079 9999 (40 TU)
    • Modify both longitudinal members: 5080 9999 (130 TU)
• Diagnostic Time: GFF (No allowance – 0 TU)
• Road Test Time:
  • 3 Road tests prior to the service procedure: 0121 9999 (30 TU)
  • Road test after the service procedure: 0121 0004 (10 TU)
• Claim Comment: As per TSB #2062633/1.

All warranty claims must adhere to the Audi Warranty Policies and Procedures Manual and are subject to review or audit by Audi Warranty.

Source: NHTSA ID: 10189323