Audi A3 8P Cruise Control Retrofit with VCDS: Troubleshooting Guide

This guide outlines the steps and common issues encountered when retrofitting cruise control in an Audi A3 8P using VCDS (Vag-Com Diagnostic System). We’ll cover the installation process, coding procedures, and troubleshooting tips for a successful retrofit.

Installing the Cruise Control Stalk

The first step is to install the new cruise control stalk, part number 8P0 953 513 D. This stalk is compatible with the Audi A3 8P and integrates seamlessly with the existing steering wheel controls.

Coding the Steering Wheel Electronics with VCDS

After installing the stalk, you need to code the steering wheel electronics module using VCDS:

1. Select Module: Connect VCDS to your vehicle’s OBD-II port and select “16 – Steering Wheel.”

2. Access Coding: Navigate to “07 – Coding.”

3. Modify Coding: Change the coding from 0000012 to 0000042. This change enables the cruise control functionality in the steering wheel module. The coding digits represent different options:

   • 0: No Board Computer, No Cruise Control
   • 1: Board Computer, No Cruise Control
   • 2: No Board Computer, Cruise Control
   • 4: Board Computer, Cruise Control

Coding the Engine Control Module (ECM) with VCDS

Next, code the engine control module to recognize the new cruise control system. In some Audi A3 8P models, “Coding II” may be grayed out. If this is the case, use “Long Coding” instead:

1. Select Module: In VCDS, select “01 – Engine.”
2. Access Long Coding: Go to “Long Coding Helper.”
3. Enable Cruise Control: Scroll to Byte 0 (sometimes Byte 1 depending on the specific ECM) and Bit 6. Check the box labeled “Cruise Control installed.”

Troubleshooting Common Issues

Even after correctly following these steps, you might encounter issues. One common problem is a fault code 01044 - Control unit incorrectly coded in module 16 - Steering wheel. This indicates a coding error within the steering wheel electronics.

Possible Solutions:

• Double-Check Coding: Verify that you entered the correct coding values in both the steering wheel and engine control modules. Even a single digit error can prevent cruise control from functioning.
• Security Access: In some cases, you may need to access “Coding II” in the engine control module using a security access code. Consult your vehicle’s documentation or online resources for the correct code. Commonly, the code 11463 is used for engine module access. If “Coding II” is accessible, try coding the module using the traditional method instead of long coding.
• Check Wiring: Ensure all connections to the new cruise control stalk are secure and properly seated.

Further Diagnostics with VCDS Auto-Scan

If the problem persists, perform a full Auto-Scan using VCDS before and after coding changes. This scan provides a comprehensive report of all modules and any fault codes present. Comparing the scans can help pinpoint the source of the issue. Below are examples of pre and post coding auto-scans.

By carefully following the steps outlined in this guide and utilizing VCDS for diagnostics, you can successfully retrofit cruise control in your Audi A3 8P. Remember to double-check your coding and consult online resources or forums for assistance if needed.