2025 Audi A5/Q5 Exhaust Emissions Warning TSB 2080114/1

Symptoms

Owners of certain 2025 Audi A5 and Q5 models, including the A5 (FU), Q5 (FU), and Q5 Sportback (GU) equipped with the 4-cylinder 2.0 TFSI engine, may observe the 'exhaust emissions warning lamp' illuminating in their instrument cluster. This warning is the primary indicator of the underlying issue described in Audi TSB 2080114/1.

Fault Codes and Diagnostic Trouble Codes (DTCs)

When the 'exhaust emissions warning lamp' activates due to this condition, the vehicle's Engine Control Module (ECM), specifically the J623 unit (address word 0001), will log a specific Diagnostic Trouble Code (DTC):

This P01C400 fault is specifically identified as "Fuel rail pressure sensor 1 range/performance" and is associated with symptom code 46314. The presence of this code points directly to the underlying software anomaly within the Engine Control Unit.

Technical Background and Cause

Audi has identified the root cause of the illuminated 'exhaust emissions warning lamp' and the stored DTC P01C400 as a software issue within the Engine Control Unit (ECU). This software anomaly leads to an incorrect interpretation or detection of a range or performance fault in the fuel rail pressure sensor. It is crucial to understand that this is not a mechanical failure of the sensor itself, but rather a misinterpretation by the vehicle's software.

The TSB (2080114/1) clarifies that this is a software-related problem, not a hardware defect requiring component replacement. The issue specifically affects the engine control module's ability to accurately monitor and report on the fuel rail pressure sensor's operation, leading to the erroneous fault code and warning light.

Important Warnings and Current Status

Audi has issued critical guidance for both owners and service technicians regarding this condition. The manufacturer explicitly states that "no repairs are necessary at this point" and that owners will be advised if any action is determined to be needed. This means that while the warning lamp may be active, there is no immediate safety concern or need for urgent repair.

A key warning from Audi is: "Do not replace any components for this condition since this will not resolve the customer's concern." This advisory is vital, as attempting to replace the fuel rail pressure sensor or other related components will not fix the underlying software problem and could result in unnecessary costs or wasted effort. Furthermore, this TSB (2080114/1) is currently "informational only and not applicable to any Audi Warranty" at this time, indicating that a formal repair procedure under warranty is not yet established.

As of the TSB's release date of November 25, 2025, a permanent solution for the 2025 Audi A5 P01C400 issue is actively "under development." Audi anticipates updating this bulletin once more information and a definitive fix become available. This "Production Solution" will likely involve a software update to the Engine Control Unit.

What Owners Should Do

If you own a 2025 Audi A5 or Q5 (FU or GU chassis codes) with the 4-cylinder 2.0 TFSI engine and observe the 'exhaust emissions warning lamp' illuminated, especially if accompanied by DTC P01C400, you should contact your authorized Audi dealer. While no immediate repair is available, your dealer can document the issue.

The TSB instructs dealerships to "Create a PSS record in the PSS application through the Pending Service Solutions (PSS) link in AccessAudi (under Related Links >> Service)." This process helps Audi track affected vehicles and ensures that you are notified directly when the software update or other resolution is officially released. It is important to remember Audi's directive: do not attempt to replace parts, as this will not resolve the 2025 Audi A5 P01C400 issue.

Since this is a known software issue with a solution pending, patience is advised. Your dealer will be your primary point of contact for updates on when the fix becomes available.

Required Parts and Tools

The TSB explicitly states that "Required Parts and Tools" are "Not applicable" at this stage. This reinforces that this is a software-related issue awaiting a digital solution rather than a mechanical repair requiring physical components or specialized equipment.

Source: NHTSA ID: 11026282, Transaction No.: 2080114/1.