2021-2024 Audi C11DF29 Rack Position Implausible TSB

Audi has released Technical Service Bulletin (TSB) 2068822/2 to address a specific issue affecting the rear-wheel steering system in certain 2021-2024 Audi models. This bulletin, revised on June 29, 2023, supersedes an earlier bulletin, 22-37, dated December 7, 2022. The primary concern is the illumination of the steering warning lamp accompanied by a diagnostic trouble code (DTC).

Symptoms

Owners of affected Audi vehicles may notice that "The steering warning lamp is on" in their instrument cluster. This visual alert indicates a potential problem with the vehicle's steering system. This symptom is directly linked to a software issue within the rear-wheel steering control unit.

Fault Codes / DTCs

When the steering warning lamp is illuminated, a technician performing a diagnostic scan will find the following fault code stored in the vehicle's system:

Code	Description	Module	Symptom Code
C11DF29	"Rack Position Implausible"	J1019 rear-wheel steering (address word 00CB)	205

This DTC C11DF29 "Rack Position Implausible" specifically points to an issue with the rack position sensor's readings within the J1019 rear-wheel steering control unit.

Diagnosis / Trigger Conditions

The root cause of the C11DF29 fault code and the illuminated steering warning lamp has been identified as a software issue. This means the hardware components of the rear-wheel steering system are not necessarily faulty, but rather the software controlling them is providing incorrect or implausible data regarding the rack's position. The condition is triggered by this software anomaly within the J1019 control unit.

Repair Procedure Summary

The resolution for the Audi A7 C11DF29 rack position implausible issue involves updating the software of the J1019 rear-wheel steering control unit. This procedure is performed using the Software Version Management (SVM) system. Technicians must follow the instructions detailed in TSB 2011732, which outlines the general SVM operating procedures.

Specifically, the J1019 control unit (address word 00CB) needs to be updated using the SVM action code 44A037. The update will transition the software from the old version, 4M0909145E (0698), to the new version, 4M0909145E (0699). This software update is designed to correct the logic that causes the "Rack Position Implausible" error.

Required Tools or Parts

To perform this repair, a certified Audi technician will utilize the Software Version Management (SVM) system. This system allows for the electronic update of vehicle control units. The specific SVM action code required for this update is 44A037. No physical parts are replaced; the repair is entirely software-based.

Warranty Information

This software update for the C11DF29 fault is covered under Audi's New Vehicle Limited Warranty for up to 48 months or 50,000 miles, whichever comes first. For Audi Certified Pre-Owned (CPO) vehicles, the repair is covered under claim type G10. If the vehicle is outside of any applicable warranty, this Technical Service Bulletin serves as informational guidance, and the repair costs may be borne by the owner. The service number for this operation is 4841, with a damage code of 0040. The labor operation for the software update, including checking for DTCs, is 0151 0000. Diagnostic time is GFF, with no allowance for road tests before or after the procedure.

Owner Action

If you experience the steering warning lamp illuminated in your 2021-2024 Audi A7, SQ7, SQ8, or RS Q8, or if a diagnostic scan reveals the DTC C11DF29 "Rack Position Implausible", it is recommended to contact your authorized Audi dealership. They will be able to diagnose the issue and perform the necessary software update to resolve the problem. Since this is a software-related repair, it typically does not require extensive time in the service bay.

NHTSA ID: 10238356