2021-2023 Audi e-tron AC Noise from Compressor TSB

Symptoms

Owners of 2021-2023 Audi e-tron, including e-tron quattro and e-tron Sportback quattro models, may experience a noticeable noise inside the cabin when the air conditioning system is active. This noise is particularly evident when the AC compressor is running. A key indicator of this issue is that the noise completely disappears when the air conditioning system is turned off. This specific symptom helps differentiate it from other potential vehicle noises.

Technical Background

Audi has identified that the primary cause of this cabin noise is vibration transfer. The vibration originates from the air conditioning compressor when it's operating. This vibration is then transmitted into the vehicle's cabin due to direct contact between various components in the front motor compartment.

Specifically, the TSB highlights two main areas of contact:

• Adjacent refrigerant lines making contact with each other.
• A refrigerant line making contact with the Bowden cable clip, which is used for the front hood release.

When these components touch, the vibrations from the active AC compressor are effectively amplified and transferred, resulting in the audible Audi e-tron AC noise inside the vehicle. Workshop findings confirm that this symptom is easily reproducible and the noise source is external to the cabin.

Diagnosis and Trigger Conditions

Technicians diagnosing the Audi e-tron AC noise will look for several potential contact points that could be causing the vibration transfer. The TSB outlines a comprehensive inspection process to identify these specific areas:

• Refrigerant Line Contact: Inspect for any direct contact between adjacent refrigerant lines (as shown in Figure 1 and Figure 3 of the TSB).
• Bowden Cable Clip Interference: Check for contact between a refrigerant line and the Bowden cable clip for the front hood release (Figure 2 and Figure 7). The refrigerant line containing the service port is a common area for this type of interference.
• Coaxial Refrigerant Line Contact: An additional point of contact may occur where the coaxial refrigerant line crosses the refrigerant line containing the service port (Figure 8).
• Compressor Isolator Seating: The compressor isolator spring might not be correctly indexed in its rubber mounting, leading to an improperly seated compressor isolator assembly (Figure 9). This can create a gap between the rubber isolator and the mounting bracket.
• Service Port Mounting Interference: Inspect the service port mounting block for interference with an adjacent line (Figure 11).

These conditions trigger the vibration and subsequent noise when the AC system is active, making them crucial diagnostic points for resolving the Audi e-tron AC noise.

Repair Procedure Summary

The repair for the Audi e-tron AC noise focuses on eliminating the identified contact points to prevent vibration transfer. The general procedure involves separating and securing components that are making contact.

1. Front Storage Compartment Removal: The initial step requires removing and reinstalling the front storage compartment to gain access to the affected areas.
2. Separate Refrigerant Lines: Any refrigerant lines found to be in direct contact with each other or with the Bowden cable clip must be separated. Technicians will use a hose holder, clip, or tie-wrap to secure these lines in a separated position (Figure 5 and Figure 6). Special attention is given to the refrigerant line containing the service port, ensuring it's secured away from the Bowden cable clip.
3. Compressor Isolator Inspection and Correction: If the compressor isolator spring is found to be improperly seated, the spring and/or rubber mount will be twisted to correctly index them. This ensures the isolator assembly lies flat against its bracket (Figure 10).
4. Service Port Clearance: For any interference found at the service port mounting block, the service port will be gently pushed to create a permanent clearance from the adjacent line (Figure 12).

This procedure aims to ensure all components have adequate clearance, preventing the vibrations from being transmitted into the cabin.

Warranty Information

This Technical Service Bulletin (TSB 2063467/4) outlines specific warranty claim types for addressing the Audi e-tron AC noise.

• Standard Warranty: Repairs performed under this TSB are covered under the standard warranty for up to 48 months or 50,000 miles, whichever comes first. The claim type for this is 110.
• Certified Pre-Owned (CPO) Vehicles: For CPO vehicles, the claim type is G10, but verification of owner eligibility is required.
• Out-of-Warranty Vehicles: If the vehicle is outside of any applicable warranty period, this Technical Service Bulletin serves as informational guidance only, and repair costs may be the owner's responsibility.

The damage code associated with this issue is 0020, and the service number is 8744. All warranty claims must adhere to the Audi Warranty Policies and Procedures Manual and are subject to review by Audi Warranty.

Source: NHTSA ID: 10217904