2025-2026 Audi A5/Q5/S5 Instrument Cluster Messages TSB

Owners of certain 2025-2026 Audi A5, S5, Q5, and SQ5 models may experience various warning messages appearing in their instrument cluster. This issue, detailed in Audi Technical Service Bulletin (TSB) 2079930/3, is often accompanied by diagnostic trouble codes (DTCs) such as U02AB00 and U042200, and can prevent diagnostic tools from communicating with certain control units.

This TSB, released on December 17, 2025, outlines a software-related problem within the vehicle's electrical system. It supersedes a previous bulletin, TSB 2078345, indicating an updated approach to resolving these persistent communication and warning issues. The primary fix involves a software update to the affected control unit.

Symptoms Owners May Notice

Drivers may observe a range of warning messages displayed in their instrument cluster, indicating various system malfunctions. These Audi instrument cluster messages U02AB00 and other related warnings can be concerning and impact vehicle operation. Verbatim messages reported by customers include:

• "Drive system: fault. Limited performance. Please contact workshop"
• "Loose wheel warning: fault. See owner's manual."
• "Tire pressure: fault. See owner's manual."
• "Initializing active front assist. Please wait..."
• "Brakes: function restricted. You can continue driving cautiously. Please contact workshop."
• "Fault in cooling system"

These messages suggest a broad impact on the vehicle's systems, from powertrain to safety features, all stemming from the underlying communication issue.

Fault Codes and Diagnostic Issues

When diagnosing the problem, technicians may find that diagnostic addresses 00C5 and 8132 cannot be reached. Furthermore, specific Diagnostic Trouble Codes (DTCs) are commonly stored in the Engine electronics control unit (J623, address word 0001):

• U02AB00: "Thermal management control unit no communication (active/static)." This code indicates that the engine control unit is not receiving expected communication from the thermal management control unit.
• U042200: "Invalid data received from body control module (active/static)." This suggests a problem with data integrity or communication from the body control module.

For vehicles equipped with 2.0L TFSI engines (engine codes DWZA, DWZB, or DXCA), an additional DTC may be logged:

• P021700: "Engine Coolant Over Temperature Condition – symptom 47156." This specific code points to an engine overheating condition, which could be a secondary symptom of the communication fault affecting thermal management.

Diagnosis and Trigger Conditions

The root cause of these Audi instrument cluster messages U02AB00 and other related issues is identified as a software problem within the onboard supply control unit, designated as J519. This software glitch interferes with proper communication between various vehicle modules, leading to the observed warning messages and stored DTCs. The problem is not related to a production defect that requires a hardware change, but rather a software anomaly that needs an update.

Repair Procedure Summary

The repair procedure for addressing these instrument cluster warnings and DTCs, as outlined in TSB 2079930/3, focuses on restoring proper communication and updating the vehicle's software. The steps are as follows:

1. Terminal 30 Reset: The first step involves performing a terminal 30 reset for a minimum of 15 minutes. This procedure helps to reset various control units and can often restore communication to diagnostic addresses 00C5 and 8132, which may have been previously unreachable.
2. Software Update Check: After the reset, technicians must check if Technical Service Bulletin 2079690, titled "00 Combined software update 03.10.00/C (28.13.01) KD2," is applicable and visible for the specific vehicle. This indicates that a comprehensive software update package is available.
3. Software Update Implementation: If TSB 2079690 is applicable, the software update described within that bulletin must be performed. This update is designed to correct the underlying software issue in the J519 onboard supply control unit, resolving the communication problems and consequently eliminating the Audi instrument cluster messages U02AB00 and other related warnings.

Warranty Information

Audi provides specific guidelines for warranty claims related to this Technical Service Bulletin 2079930/3. If the vehicle is outside of its warranty period, this bulletin serves as informational guidance only, meaning the repair may not be covered free of charge.

For in-warranty repairs, the following details apply:

• Service Number: 9710
• Damage Code: KD02
• Labor Operations:
  • 0151 0010: Software update, including connecting a battery charger. This operation is billed according to the Service Repair Time (SRT) with associated operations.
  • 0151 0040: Fixed rate for the software update, which includes all necessary preliminary and follow-up work. This encompasses tasks such as managing the bus sleep cycle, performing a calibration drive, and any additional work required if the software flashing process is interrupted. This is allocated 130 time units (TU).
  • 9785 0999: Loosening and securing the ground cable, allocated 20 TU.
  • 0150 9999: For additional attempts required due to flash cancellation, a lump sum of 50 TU is permitted per documented attempt.
• Claim Comment: Claims should reference "As per TSB 2079930/3."

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

Important Warnings

Owners should be aware that if their vehicle is no longer under warranty, this Technical Service Bulletin is provided for informational purposes only. The cost of diagnosis and repair may not be covered by Audi. It is always recommended to consult with an authorized Audi service center to confirm warranty eligibility and discuss potential costs.

Owner Action

If you are experiencing various warning messages in your instrument cluster, or if your vehicle has stored DTCs like U02AB00 or U042200, it is recommended to schedule an appointment with an authorized Audi service center. Inform them about the specific symptoms and mention Technical Service Bulletin 2079930/3. The service center will perform the necessary diagnostic steps and apply the required software update to resolve the issue.

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Source: NHTSA ID: 11027394

FAQs

Q1: What are the common warning messages I might see in my Audi's instrument cluster? A1: You might see messages such as "Drive system: fault. Limited performance. Please contact workshop," "Loose wheel warning: fault. See owner's manual," "Tire pressure: fault. See owner's manual," "Initializing active front assist. Please wait...", "Brakes: function restricted. You can continue driving cautiously. Please contact workshop," or "Fault in cooling system."

Q2: What specific diagnostic trouble codes (DTCs) are associated with these instrument cluster issues? A2: The primary DTCs are U02AB00, indicating "Thermal management control unit no communication," and U042200, for "Invalid data received from body control module." For 2.0L TFSI engines, P021700, "Engine Coolant Over Temperature Condition," may also appear.

Q3: How is the issue of Audi instrument cluster messages U02AB00 resolved? A3: The problem is resolved by performing a terminal 30 reset, followed by a software update to the onboard supply control unit J519, as detailed in Audi Technical Service Bulletin 2079930/3 and referenced TSB 2079690.

Q4: Is this repair covered under warranty? A4: Yes, if your vehicle is still within its warranty period, the repair is typically covered by Audi. Specific labor operations and time units are provided for technicians to claim the repair under warranty. If your vehicle is outside of warranty, the bulletin is informational, and costs may apply.