2025-2026 Audi A5/Q5/S5 Loose Wheel Warning TSB 2077226/7

Audi has released Technical Service Bulletin (TSB) 2077226/7 to address concerns regarding the illumination of a "loose wheel warning" or a general tire pressure warning message in certain 2025-2026 Audi A5, Q5, and S5 vehicles. This bulletin provides comprehensive guidance for technicians to diagnose and resolve these alerts, which may appear in combination with other messages on the instrument cluster.

The TSB emphasizes that while a software update is often the primary solution, technicians should be prepared to perform additional diagnostic steps if the issue persists. Owners experiencing an Audi A5 loose wheel warning or similar alerts should be aware of the steps outlined in this communication.

Symptoms

Owners of affected Audi models may observe an active "loose wheel warning" or a "tire pressure warning" displayed on their vehicle's instrument cluster. These warnings indicate a potential issue with the wheel or tire pressure monitoring system. The TSB notes that these alerts might not appear in isolation but could be accompanied by other messages, suggesting a broader system interaction.

Upon investigation, workshop findings confirm that the complaint can be reproduced, and various Diagnostic Trouble Codes (DTCs) may be logged in the vehicle's control units. Addressing the underlying cause of the Audi A5 loose wheel warning is crucial for vehicle safety and proper function.

Diagnosis and Trigger Conditions

When a customer reports a "loose wheel warning" or tire pressure alert, technicians are advised to follow a structured diagnostic approach. While the primary recommendation is a software update, if the issue persists or the update is not immediately available, further investigation is necessary. This includes checking specific control unit addresses for relevant DTCs.

Technicians should examine control unit addresses 812C, 0003, and 0065 for any stored fault codes. These addresses are critical for the proper functioning of the wheel and tire pressure monitoring systems. If DTCs are logged for individual wheels or all four wheels, performing wheel balancing or swapping the wheels may help to resolve the issue. Additionally, it is essential to ensure that the speed sensors and their corresponding sensor rings for the affected wheels are clean and operating correctly, as these components provide vital data for the system.

Should problems with the overall availability of the system be detected, the TSB directs technicians to correct these issues using the Guided Fault Finding procedure. This systematic diagnostic process helps pinpoint complex electrical or communication faults. Furthermore, technicians are instructed to check for DTCs in other related control units and consult specific further TSBs, such as 2078345, which may identify additional causes for the Audi A5 loose wheel warning or tire pressure alerts. These related TSBs can provide insights into the chain of effects leading to the warning message in the instrument cluster.

Repair Procedure Summary

The primary repair procedure outlined in TSB 2077226/7 involves performing a software update. This update is detailed in TSB 2079690, titled "00 Combined software update 03.10.00/C (28.13.01) KD2." The software update aims to recalibrate or optimize the vehicle's systems to prevent erroneous "loose wheel warning" or tire pressure messages.

During the software update process, it is crucial to connect a battery charger to maintain stable voltage, ensuring the update completes successfully. The TSB specifies labor operations for this process, including a fixed rate for the software update, which covers all necessary preliminary and follow-up work, such as bus sleep cycle management and calibration drives. If a flash abort occurs during the update, additional time units can be claimed for subsequent attempts.

If the complaint persists even after the software update, or if the vehicle is a 2026 model year, technicians should proceed with the detailed diagnostic steps mentioned above. This includes checking control unit addresses 812C, 0003, and 0065 for DTCs, considering wheel balancing or swapping, inspecting speed sensors and rings, and utilizing Guided Fault Finding. Consulting TSB 2078345 for related issues is also a recommended step to comprehensively address the Audi A5 loose wheel warning.

Important Warnings

Audi emphasizes a critical point regarding these warnings: "Loose wheel warning and tire pressure messages are often a result of other issues with the vehicle, therefore the main cause should be rectified first." This means that simply clearing the warning or performing a superficial fix without addressing the root cause will likely lead to a recurrence of the problem. Technicians are advised to conduct thorough diagnostics to ensure the actual underlying issue is identified and corrected.

Warranty Information

For vehicles still under warranty, the repairs outlined in TSB 2077226/7 are typically covered. The TSB specifies a Service Number of 4545 and a Damage Code of KD02 for warranty claims. Labor operations for the software update include 0151 0010 for the software update with battery charger connection, 0151 0040 for a fixed rate covering all related work (130 time units), and 0150 9999 for additional attempts after a flash abort (50 time units per attempt).

All warranty claims must be submitted in accordance with the Audi Warranty Policies and Procedures Manual and are subject to review by Audi Warranty. For combined software updates, timestamps are not required for billing under warranty, allowing technicians to work on other vehicles concurrently. Furthermore, these combined software updates can be performed by non-productive personnel, streamlining the service process.

If the vehicle is outside of its warranty period, this Technical Service Bulletin serves as informational guidance for diagnosis and repair, but the associated costs would typically be borne by the owner.

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NHTSA ID: 11028455