2025-2026 Audi Driver Assist Warning TSB U171200

Audi has released Technical Service Bulletin (TSB) 2080929/1, also identified as 90 PSS PPE/PPC, to address customer complaints regarding various driver assist system warning messages. This issue affects certain 2025-2026 Audi A5, A6, Q5, S5, and SQ5 models. Owners may notice a "take over steering prompt" appearing shortly after starting the vehicle, often accompanied by other driver assistance system fault messages. This TSB supersedes previous bulletin 2079757.

The core problem behind these alerts is a software issue, which also logs the diagnostic trouble code (DTC) U171200. Understanding this Audi driver assist U171200 issue is crucial for owners to avoid unnecessary repairs and ensure proper resolution.

Symptoms of the Driver Assist Malfunction

Owners experiencing this issue will typically observe a "take over steering prompt" on the instrument cluster, often represented by a red warning lamp depicting a steering wheel with hands. This prompt appears shortly after the vehicle is started. Depending on the specific equipment in the vehicle, this may be accompanied by a range of other driver assist system fault messages. These messages indicate a temporary malfunction of various assistance features.

Common verbatim warning messages that may appear include:

• "Adaptive cruise assist: fault. You can continue driving"
• "Lane departure warning: fault. You can continue driving"
• "Active front assist / distance warning: fault. You can continue driving"
• "Traffic sign recognition: fault. You can continue driving"
• "Adaptive light: fault"
• "Main beam assist: fault"
• "Lane change assist: currently unavailable"
• "Proactive occupant protection: currently unavailable"
• "Driver assist systems currently restricted"
• "Emergency Assist: fault. You can continue driving"

These messages indicate that while the vehicle may still be drivable, the specified driver assistance functions are either faulty, restricted, or unavailable. The presence of these symptoms, particularly the "take over steering prompt," is key to identifying the Audi driver assist U171200 problem.

Diagnostic Trouble Code (DTC) U171200

When these symptoms occur, technicians will typically find the Diagnostic Trouble Code (DTC) U171200 logged in the vehicle's systems. The full description for this code is "Driver assistance main control module, no communication, active/static with symptom 4540." This DTC is specifically logged in the Data Bus Diagnostic Interface Control Unit, J1273, which is found at diagnostic address 0019.

For this TSB to apply, the diagnostic addresses 00A5 and 8103 must also be inaccessible, meaning they cannot be read out during diagnosis. The simultaneous occurrence of active warning messages, inaccessible diagnostic addresses 00A5 and 8103, and the logged DTC U171200 confirms the specific condition addressed by TSB 2080929/1.

Important Warnings for Owners

Audi has issued several critical notices within TSB 2080929/1 that owners should be aware of to prevent unnecessary diagnosis or repairs:

• Applicability: "If the red warning lamp for the take over steering prompt (Figure 1) is not active, this TSB does NOT apply." This means if you are not seeing the specific steering warning light, your issue may be different.
• Specific Faults: "If only some of the fault messages listed above have occurred or are active, this TSB does NOT apply." The TSB is for a specific combination of faults, not isolated warnings.
• Visibility Restrictions: "The TSB is also NOT applicable if notifications are displayed stating various driver assist systems are not available due to restricted visibility." Environmental factors like heavy rain or snow can cause temporary sensor obstructions, which are not covered by this TSB.
• No Component Replacement: "Do not replace any components for this condition since this will not resolve the customer's concern." This is a crucial warning. Replacing parts like control modules or sensors will not fix the underlying software issue and will result in wasted time and money.
• Warranty Implications: "Replacing parts or attempting repairs will not fix the problem. Unjustified work/replacement parts will be charged back. Invoicing under warranty is not permitted." Owners should be aware that if a dealership performs unauthorized or unnecessary repairs for this specific condition, the costs may not be covered under warranty.

Understanding the Technical Issue

The root cause of the Audi driver assist U171200 fault is identified as a software issue within the Data Bus Diagnostic Interface Control Unit, J1273. This control unit, located at diagnostic address 0019, experiences a communication problem shortly after the ignition is switched on. This software glitch leads to the various driver assist system warnings and the logging of DTC U171200.

Interestingly, the complaint is often temporarily remedied by a "bus sleep cycle." A bus sleep cycle occurs when the vehicle's electrical system powers down after the ignition is turned off, the vehicle is locked, and approximately three minutes have passed. This power cycle effectively resets the control unit, and the fault messages clear for the subsequent driving cycle. However, the issue may reoccur after another vehicle startup.

Manufacturer's Advice and Repair Strategy

For vehicles exhibiting the symptoms and DTC U171200 as described, Audi's current guidance under TSB 2080929/1 is as follows:

1. Inform the Customer: Dealerships are instructed to explain to customers that a permanent software solution is currently under development and is expected to be available by the end of the second quarter of 2026. This timeline is subject to change.
2. No Immediate Repairs: At this time, no physical repairs or component replacements are necessary. The issue is software-based, and replacing hardware will not resolve it.
3. PSS Record Creation: Technicians are required to create a Pending Service Solutions (PSS) record in the Audi Now system. This helps Audi track the prevalence of the issue and ensures that affected vehicles are documented for future software updates.

Owners should not expect a repair that involves replacing parts for this specific condition. The focus is on a future software update to permanently resolve the communication issue in the Data Bus Diagnostic Interface Control Unit, J1273.

Source: NHTSA Manufacturer Communication 11029420