2021-2022 Audi Q-Series Airbag Light DTC B101C29 B101D29

Symptoms of an Airbag System Issue

Owners of affected Audi vehicles may observe the following symptom:

• The airbag light is on.

This warning light indicates a potential issue with the vehicle's supplemental restraint system, which includes airbags and seat belt pretensioners.

Diagnostic Trouble Codes (DTCs)

When the airbag light illuminates, a scan of the vehicle's systems may reveal specific Diagnostic Trouble Codes (DTCs) stored in the airbag control module (J234, address word 0015). Technical Service Bulletin 2064545/1 specifically addresses the following codes:

These codes indicate that the airbag control module is receiving an unexpected or incorrect signal from either the driver's or front passenger's seat belt buckle switch.

Understanding the Issue

Audi has issued TSB 2064545/1 to gather more information regarding the Audi Q8 airbag light condition. The technical background indicates that various parts have been replaced under warranty for this condition, but no definitive issues were identified with those parts. As a result, Audi is requesting detailed photographic evidence from technicians to aid in their ongoing analysis of the problem. This suggests that the root cause is not yet fully understood or consistently reproducible. No changes have been made to production vehicles as no specific issue has been identified in manufacturing.

Diagnostic Steps for the Audi Q8 Airbag Light

For vehicles presenting with an illuminated airbag light and DTC B101C29 and/or B101D29, technicians are instructed to follow a detailed diagnostic procedure to assist Audi in their investigation. This process focuses heavily on visual inspection and documentation:

1. Verify Customer Concern: Confirm that the airbag light is indeed illuminated.
2. Detailed Photo Documentation: Before any repairs are attempted, technicians must take comprehensive photos of several components:
   • The seat belt buckle with its latching mechanism (Figure 1 in the TSB).
   • The wiring harness connecting the belt buckle to the seat frame (Figure 2 in the TSB).
   • The belt buckle wiring and its connector located on the seat frame (Figure 3 in the TSB).
   • The belt buckle wiring and connector within the seat coupling point underneath the seat (Figure 4 in the TSB).
3. Perform Root Cause Analysis: Technicians are expected to conduct a thorough investigation to determine the underlying cause of the implausible signal.
4. Component Inspection: Carefully inspect the seat belt buckle for any foreign objects or sticky fluids. Additionally, examine the belt buckle wiring for any signs of damage and the connectors for issues such as damaged wiring, backed-out pins, widened pins, or corrosion.
5. Document Findings: Take additional detailed photos of any concerns discovered during the analysis.
6. Upload and Reference: All collected photos must be uploaded to the Doc-It system, and the TSB number 2064545/1 must be referenced in the claim comments.

Important Information for Owners

Owners should be aware that this Technical Service Bulletin 2064545/1 is primarily informational and diagnostic in nature. It is not applicable to any Audi Warranty. This means that any diagnostic work or potential repairs stemming from this issue may not be covered under your vehicle's standard warranty. If your Audi Q8 airbag light is on, it is crucial to understand that the dealer's actions will be focused on gathering data for Audi's engineering teams.

Source: NHTSA ID 10201506