2021-2023 Audi Intersection Assist Fault C12BFF0 TSB

Owners of certain 2021-2023 Audi models, including the Audi e-tron, may encounter issues with their intersection assist and lane change assist systems becoming inoperative. This condition is often accompanied by specific warning messages in the instrument cluster and a Diagnostic Trouble Code (DTC) C12BFF0 stored in the vehicle's control modules.

Symptoms

If your Audi is affected by this issue, you may notice that the intersection/lane change assist systems are not working. One or more of the following messages will be displayed in your instrument cluster:

• "Intersection assist: fault. Please contact workshop."
• "Side assist and exit warning system: fault. Please contact workshop."
• "Rear cross-traffic assist: fault. Please contact workshop."
• "Audi pre sense: fault. Please contact workshop."

Fault Codes / DTCs

Technicians investigating this issue will likely find the following DTC stored in the lane change assist control modules (J769/J770) or the radar sensor control module for object detection (J1088/J1089):

Code	Description
C12BFF0	Radar sensor automatic calibration not possible.

This DTC, C12BFF0, indicates a problem with the automatic calibration of the radar sensors.

Diagnosis / Trigger Conditions

The radar sensors responsible for these assist systems continuously calibrate themselves based on the vehicle's surroundings while driving above a certain speed. The DTC C12BFF0 is stored if the calculated dynamic angle offset exceeds +/-5° during this automatic calibration process. This triggers the fault messages in the instrument cluster, indicating an issue with the Audi e-tron C12BFF0 condition.

Possible Causes

Audi has identified several potential causes for the inoperative assist systems and the stored Audi e-tron C12BFF0 fault code:

• Loose or improperly seated sensors: Sensors may not be fully secured in their mounts.
• Incomplete sensor calibration: This can occur after a sensor replacement.
• Obstructions in sensor field of view: Decals, stickers, or NFC tags on the bumper cover (inside or outside) can interfere.
• Excessive dirt: Dirt on the bumper cover (inside or outside) can block sensor visibility.
• Bumper cover damage: Physical damage to the bumper cover in the sensor's field of view.
• Inadequate paintwork: Paint repairs on the bumper cover that affect the sensor area.
• Non-conforming paintwork: Paintwork on the bumper cover (inside or outside) that does not meet specifications.

Repair Procedure Summary

Before proceeding with sensor replacement, technicians should first check for and remedy the possible causes listed above. If the cause is not clearly identifiable or if sensor calibration continues to fail, the following steps are recommended:

1. Reseat the sensor: Remove the affected sensor from its mount and then reseat it properly. Afterward, perform calibration again.
2. Swap sensors (if calibration fails again): If reseating doesn't resolve the issue, swap the left and right sensors. After swapping, a full replacement procedure must be performed using ODIS-S to ensure the correct data set is available for subsequent calibration. Once activated, perform calibration again.

To calibrate the sensors, the dynamic calibration procedure is the preferred method. This TSB emphasizes that simply replacing the radar sensor without clear findings will not resolve the Audi e-tron C12BFF0 issue.

Important Warnings

Audi explicitly states: "Replacing the corresponding radar sensor without clear findings will NOT resolve the issue." This means that technicians should thoroughly investigate and address the underlying causes, such as sensor seating or obstructions, before considering sensor replacement. Unnecessary sensor replacement will not fix the problem and could lead to additional costs.

Warranty Information

This service bulletin outlines warranty claim types for this issue:

• Standard Warranty: Applicable for vehicles up to 48 months or 50,000 miles.
• CPO Covered Vehicles: G10 claim type for Certified Pre-Owned vehicles, subject to owner verification.

All warranty claims must adhere to the Audi Warranty Policies and Procedures Manual.

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Source: NHTSA ID: 10197970