2025-2026 Audi Generic Scan Tool Errors TSB 2078765/2

Symptoms

Owners of affected 2025-2026 Audi A5, S5, Q5, SQ5, and A6 vehicles may encounter difficulties when attempting to perform vehicle inspections or exhaust emissions tests using a generic scan tool (GST). The primary symptom is that the test routine cannot be completed. During this diagnostic process, a message may be displayed indicating that the "diagnostic unit has received incomplete data from the vehicle."

This issue with Audi generic scan tool errors is described as occurring very occasionally. It does not trigger any dashboard warning lights, nor does it result in any warning messages being displayed in the instrument cluster. The problem is typically temporary and resolves itself without direct intervention.

Fault Codes / DTCs

This specific complaint, related to Audi generic scan tool errors, does not generate any diagnostic trouble codes (DTCs). The vehicle's onboard diagnostic system does not log any fault codes for this condition. Therefore, technicians will not find any stored DTCs when diagnosing this particular issue.

Diagnosis / Trigger Conditions

Customer reports indicate that the test routine cannot be completed during vehicle inspection or exhaust emissions tests when using a generic scan tool. The diagnostic unit may display a message about receiving incomplete data.

Workshop findings confirm that the complaint occurs very occasionally and is no longer active after a bus sleep cycle. This means the issue generally cannot be reproduced in the workshop environment, making diagnosis challenging. There are no DTCs logged for this complaint, and no warning messages are associated with it.

Technical Background

The root cause of the Audi generic scan tool errors lies within the vehicle's gateway software and its interaction with the on-board diagnostic interface. When a generic scan tool attempts to query the vehicle's diagnostic system, it may receive an incomplete response. This incomplete data leads the diagnostic tester (e.g., an OBD scanner) to respond with a cancellation message.

While a connection via the on-board diagnostic interface is possible, a portion of the query receives an incorrect response. This system behavior is temporary and is naturally remedied by a bus sleep cycle. A bus sleep cycle occurs after the ignition is switched off and the vehicle has been waiting for a period of up to several minutes. It is important to note that this specific behavior does not occur for vehicle diagnosis performed using Audi's proprietary ODIS system.

Resolution / What to Do

If you encounter Audi generic scan tool errors, the primary resolution is to allow the vehicle to complete a bus sleep cycle. This cycle initiates after the ignition is switched off and the vehicle remains undisturbed for approximately 5 minutes. After this period, a correct response should be given to any new query via the on-board diagnostic interface.

No active measures are possible if this system behavior is not currently active. The issue is self-correcting through the vehicle's normal operation.

Important Warnings

This Technical Service Bulletin (TSB) 2078765/2 explicitly states that this concern is due to a third-party system (the generic scan tool) and is not covered by any Audi Warranty. Owners should be aware that any costs associated with diagnosing or attempting to resolve this specific issue using a generic scan tool will not be covered by Audi.

Revision History

This Technical Service Bulletin, Transaction No. 2078765/2, has undergone the following revisions:

• Revision 1 (October 2, 2025): Initial publication of the bulletin.
• Revision 2 (February 19, 2026): Revised the header to add Model Year 2026 and revised the Condition section to include the updated model table.

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Source: NHTSA ID: 2078765/2