2022-2024 Audi MLBevo Emergency Call System Warning TSB

Owners of various 2022-2024 Audi MLBevo vehicles may encounter an intermittent warning message in their instrument cluster related to the emergency call system. Audi Technical Service Bulletin (TSB) 2079649/1 addresses this concern, identifying a software-related issue within the vehicle's communication modules. This TSB provides guidance for dealerships to resolve the "Emergency call function: fault" warning through specific software updates.

This bulletin, identified as Transaction No. 2079649/1, was released for publishing on October 7, 2025, indicating it is a forward-looking or pre-release document for upcoming service procedures. It specifically applies to MLBevo vehicles equipped with the ConBox High system up to Model Year 2024.

Symptoms

The primary symptom owners will notice is a warning message displayed in the instrument cluster: "Emergency call function: fault. Function restricted. Please contact workshop." This message indicates a problem with the vehicle's emergency call system, which is part of the broader Online Services and Telematics functionality. The warning is typically intermittent, meaning it may disappear after cycling the ignition off and on, or after the vehicle enters a bus sleep cycle. It does not remain permanently active.

This issue can manifest as various complaints related to the vehicle's communication and online services. These include the LTE data connection (4G) showing no function or communication malfunction, manual or automatic emergency calls being partially out of order or generating error messages, and Bluetooth connection issues such as misfire or not being activated.

Fault Codes / DTCs

While the warning message itself may appear without a static event memory entry, technicians may find intermittent Diagnostic Trouble Codes (DTCs) logged in the data bus diagnostic interface J533 (DA0019). These specific fault codes point to communication issues within the emergency call system:

• U142100: Control module for emergency call module and communication unit no communication - intermittent.
• U164200: Ethernet Emergency Call Module no communication - intermittent.

These DTCs indicate that the emergency call module control unit (J949, also identified as DA0075) is intermittently losing communication with other vehicle systems. The absence of static fault entries means the problem is not a constant failure but rather an intermittent disruption.

Diagnosis / Trigger Conditions

When diagnosing the "Emergency call function: fault" warning, technicians can reproduce or confirm the customer complaint, often with photographic evidence provided by the owner. A key diagnostic finding is the lack of static event memory entries in the emergency call module control unit and communication unit J949 (DA0075). Instead, the intermittent DTCs U142100 and U164200 are logged in the data bus diagnostic interface J533 (DA0019).

In some instances, a temporary solution might involve performing a terminal 30 reset for the emergency call module control unit and communication unit J949 (DA0075). However, this is not a permanent fix for the underlying software problem.

Technical Background

The root cause of the "Emergency call function: fault" warning and associated DTCs U142100 and U164200 is a software issue within the emergency call module control unit and communication unit J949. This module is critical for the vehicle's telematics and online services, including the automatic emergency call function, which relies on a stable LTE data connection (4G) and proper communication with other control units like the MIB3 infotainment system, OCU3, LSR, and AED2 gateway.

Production Solution

Audi plans to implement a production change to address this issue permanently with the introduction of the Model Year 2026 vehicles. This means that vehicles produced from Model Year 2026 onwards should not exhibit this particular software-related emergency call warning.

Repair Procedure Summary

Audi Technical Service Bulletin 2079649/1 serves as a reference document that closes Pending Service Solution (PSS) 2076052, titled "91 PSS ConBox High: SOS Emergency call warning in instrument cluster without relevant DTC." The primary repair involves applying a software update package designed to resolve the communication issues within the emergency call module J949.

This TSB outlines that specific update packages have been developed for various country-specific versions of vehicles, taking into account different hardware and software combinations. To perform the update, technicians are directed to follow instructions in other relevant TSBs:

• For Model Years 2022 and 2023 (including certain vehicles from 2021): A software package, referred to as "Cluster 37, customer service package," was developed to address multiple complaints across a group of control units. Technicians should refer to TSB 2076404, "00 Deployment overview for customer service packages MLB and MQB for MIB3/connectivity box/OCU3/LSR," for detailed billing and deployment instructions.
• For Model Years 2024 and 2025 (including MY2023 vehicles with DA005F >= 40xx): A separate software package, known as "Cluster 3B+ customer service package," was developed to fix several complaints. For these vehicles, technicians should consult TSB 2079416, "91 MMI: overview of customer service packages MLB and MQB for MIB3/ConBox/OCU3/AED2/gateway after UNECE deployment," for the necessary billing and deployment information.

The software update aims to correct the internal logic and communication protocols within the J949 control unit, thereby eliminating the intermittent "Emergency call function: fault" warning and related DTCs like U142100 and U164200. This approach ensures that the underlying software defect is addressed, restoring full functionality to the emergency call system and associated online services.

Important Warnings

Audi explicitly states critical information regarding this issue and its resolution:

• "Replacing parts or attempting repairs will not fix the problem. Unjustified work/replacement parts will be charged back."
• "Please do not bill repairs under this TSB. This TSB is for reference only, billing info can be found in the relevant TSB for the software update instructions."

These warnings highlight that the issue is purely software-related. Dealers are instructed not to replace hardware components, as this will not resolve the fault and will result in charges being reversed. Furthermore, this specific TSB (2079649/1) is for informational and reference purposes only regarding the billing process; actual billing information and detailed repair steps are contained within the referenced TSBs (2076404 and 2079416) that outline the software update instructions.

Owner Action

If you own a 2022-2024 Audi MLBevo vehicle and are experiencing the "Emergency call function: fault" warning in your instrument cluster, it is recommended to contact your authorized Audi dealership. Explain the symptoms you are observing, including the specific warning message and any intermittent behavior. Reference Audi Technical Service Bulletin 2079649/1, although the dealership will primarily use the referenced TSBs (2076404 or 2079416) for the actual software update procedure. Since this is a software-related issue addressed by a TSB, the repair is typically covered under warranty, but it is always best to confirm with your service advisor. The software update will resolve the underlying cause of the Audi Q8 emergency call warning and restore proper functionality to your vehicle's emergency call system.

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Source: NHTSA ID 11025292