2022-2024 Audi A3 Radiator Blind Fault & Speed Limit TSB

Owners of 2022-2024 Audi A3 vehicles may encounter a dashboard warning message related to the radiator blind system. This issue, detailed in Audi Technical Service Bulletin (TSB) 2078829/1, can lead to a displayed speed limitation and is associated with specific diagnostic trouble codes (DTCs).

The TSB, released for publishing on August 1, 2025, provides guidance for diagnosing and resolving the Audi A3 radiator blind fault by updating the engine control unit software.

Symptoms

Owners may observe a message in the instrument cluster stating: "Radiator blind: fault. Maximum speed limited to 10 mph. Please contact workshop." This indicates a problem with the active grille air shutter system. While the message suggests a severe speed limitation, it's important to note the specific warnings provided by Audi regarding this display.

Other reported complaints include general engine faults, irregular engine operation, incorrect coolant fan control, emissions control system malfunction, and incorrect engine output characteristics.

Fault Codes / DTCs

When the Audi A3 radiator blind fault occurs, one or more of the following diagnostic trouble codes (DTCs) may be logged in the engine control module (-J623-):

Diagnostic Trouble Code	Description	Storage State
P05A300	Active Grille Air Shutter "A" Control Circuit Range/Performance	Intermittent/Static
P05AF00	Active Grille Air Shutter "B" Stuck On	Static/Intermittent
P05A000	Active Grille Air Shutter "A" Stuck On	Intermittent/Static
P05B200	Active Grille Air Shutter "B" Control Circuit Range/Performance	Intermittent/Static

These DTCs are often accompanied by specific symptom codes, such as 28397 for an active radiator blind 2 sticks open, 28405 for active radiator blind 2 lost communication, 28396 for active radiator blind 1 sticks open, and 28408 for active radiator blind 1 lost communication.

Diagnosis and Trigger Conditions

The root cause of this issue is identified as an engine control unit problem. The DTCs and associated symptom codes are logged in the engine control module (-J623-). Technicians will use Guided Fault Finding (GFF) to diagnose the specific condition of the active grille air shutters.

Important Warnings and Owner Information

Audi has issued several critical clarifications regarding this issue:

• Speed Limit Discrepancy: The instrument cluster message "Radiator blind: fault. Maximum speed limited to 10 mph" is misleading. The message should actually specify "100 mph," rather than "10 mph." Furthermore, a specific notice states: "NOTICE: The maximum speed is not limited to 10 mph, as shown in the attached image."
• Temporary Remedy: The complaint can often be temporarily resolved by switching the ignition off and on again. This may clear the immediate warning.
• Fault Memory: If no fault with the components is found using Guided Fault Finding, the event memory entry can be deleted.
• Warranty: If your vehicle is outside of any applicable warranty, this Technical Service Bulletin (TSB) is for informational purposes only, meaning repairs may not be covered.

These warnings are crucial for owners to understand the actual implications of the dashboard message and to prevent unnecessary concern or misdiagnosis.

Repair Procedure Summary

The primary repair for the Audi A3 radiator blind fault is to update the engine control unit software. This software update addresses the underlying issue within the engine control unit that causes the radiator blind malfunction and the erroneous speed limitation message. The TSB 2078829/1 effectively closes a previous Product Service Solution (PSS) 2073088 related to the same issue.

Required Software and Tools

To perform the repair, the engine control unit software must be updated using the SVM code 01A332. The specific software part numbers and their target data versions are:

• Model: A3, 2.0 ltr. TFSI
  • Software Part Number: 8Y0 907 115 E, Target Data Version: 0002
  • Software Part Number: 8Y0 907 115 A, Target Data Version: 0004

Technicians will utilize Guided Fault Finding (GFF) operations for diagnosis and the software update process. The warranty claim details for this repair include Service Number 1935 and Damage Code 0016, with labor operations 0150 0010 and 0150 0060 for GFF.

Owner Action

If you own a 2022-2024 Audi A3 and experience the "Radiator blind: fault" message or any of the associated symptoms, it is recommended to contact your authorized Audi dealership. They can perform a diagnostic scan to confirm the presence of DTCs like P05AF00, P05B200, P05A000, or P05A300 and apply the necessary engine control unit software update as outlined in TSB 2078829/1. Ensure to mention the TSB number when you schedule your service appointment.

Source: NHTSA ID 11022650