2021-2023 Audi Assist Systems Inoperative DTC C12BFF0

This Technical Service Bulletin (TSB) 96 21 74 2063336/2, issued on November 24, 2021, addresses issues where the intersection assist and lane change assist systems become inoperative. This TSB supersedes an earlier bulletin, Group 96 number 21-70, dated June 10, 2021, and includes additional affected models.

Symptoms

Owners may notice that their Audi's intersection assist and lane change assist systems are inoperative. This condition is often accompanied by one of the following messages displayed in the 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."

If you experience an Audi e-tron C12BFF0 fault, these messages are a key indicator.

Fault Codes / DTCs

When these symptoms occur, technicians may find the following Diagnostic Trouble Code (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

Diagnosis and 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 threshold. If the calculated dynamic angle offset during this automatic calibration process exceeds +/-5 degrees, the DTC C12BFF0 is logged, and the corresponding fault messages appear.

Potential Causes

Several factors can lead to an Audi e-tron C12BFF0 fault and the inoperative assist systems. These include:

• Sensors that are loose or not fully seated in their mounts.
• Incomplete calibration of sensors after they have been replaced.
• Obstructions in the sensor's field of view, such as decals, stickers, NFC tags, or excessive dirt, either on the inside or outside of the bumper cover.
• Physical damage to the bumper cover in the sensor's field of view.
• Inadequate or non-conforming paintwork (e.g., paint repairs) on the bumper cover in the sensor's field of view.

Important Warnings

Audi advises that replacing the corresponding radar sensor without first identifying clear findings for the root cause will NOT resolve the issue. Technicians should thoroughly investigate the potential causes before proceeding with sensor replacement.

Repair Procedure Summary

If you are experiencing an Audi e-tron C12BFF0 fault, the repair process involves a series of diagnostic and corrective steps:

1. Initial Attempt: Check for and remedy any of the possible causes listed above. If the cause cannot be clearly identified and sensor calibration fails, the technician will remove the corresponding sensor from its mount, reseat it, and then perform calibration again.
2. Secondary Attempt (if initial fails): If calibration fails a second time, the sensors on the left and right sides of the vehicle must be swapped. 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, calibration is performed again. The dynamic calibration procedure is preferred for sensor calibration.

Warranty Information

This Technical Service Bulletin outlines the warranty coverage for this repair:

• Standard Warranty: Covered for up to 48 months or 50,000 miles.
• Certified Pre-Owned (CPO) Vehicles: Covered under G10 for CPO vehicles, subject to owner verification.
• Out of Warranty: If the vehicle is outside of any applicable warranty, this TSB serves as informational guidance only, and repair costs may apply.

Service Information for Technicians

• Service Number: 9635
• Damage Code: 0010
• Labor Operations:
  • Remove and install lane change assist control unit: 9635 19XX (single), 9635 20XX (two units)
  • Remove and install object detection control unit: 9158 19XX (single), 9158 20XX (two units)
• Diagnostic Time: GFF (0150 0000) – Time stated on the diagnostic protocol (Maximum 90 TU).
• Road Test Time: No allowance (0 TU) for pre-service road test; 10 TU (0121 0004) for post-service road test.

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Source: NHTSA ID: 10203723