Auto Hold Retrofit No need to run wires all the way to the ABS unit from the center console. All 4GX comes with this wiring factory installed. Nevertheless, note that this was done to 1AT PR code ABS module. If you have 1AS ABS module, it may still work, but it may stress your ABS unit slightly more. Example ABS Control Unit Part Numbers: SW: 4G0 907 379 G HW: 4G0 907 379 G Component: ESP PREMIUM H09 0250 Part Required: 4G927225B (OEM) Software Required: VCDS We recommend an OEM part, even if used. The aftermarket ones that we've found tend to not match the original interior colors and/or LED color. Procedure Use an interior tool to remove the leather interior trim upwards around the shifter. Lift MMI console by using two interior tools at the top half and pulling backwards towards you while you lift up. There are three tabs on the original switch that need to be released to push it from the bottom towards the top of the panel. Insert 4G927225B Reconnect connectors Reassemble Use VCDS Select Address 03 (ABS) Access authorization -> Enter Access Code 61378 or S11820 Long Coding Helper -> Byte 8 Use the call out below to change this byte to the proper value. Turn your car off and back on Clear DTCs via VCDS or OBD11 DO NOT JUST PASTE THE BELOW ABS CODING TO YOUR ABS CODING. Calculating Byte 8's Value: For our example, the original ABS long coding we'll use is: 44A70F0122E5F0804 B 00 4B near the end is Byte 8 (as they start at 00) (See below table) https://www.binaryhexconverter.com/hex-to-binary-converter 00 01 02 03 04 05 06 07 08 09 44 A7 0F 01 22 E5 F0 80 4B 00 The 8th byte in this case, 4B is binary for  0100 1011 By changing the first four digits to 1001 1011 The converted binary 10011011 to HEX is 9B So, our new long coding would be: 44A70F0122E5F080 9B 00 (See below table) https://www.binaryhexconverter.com/hex-to-binary-converter 00 01 02 03 04 05 06 07 08 09 44 A7 0F 01 22 E5 F0 80 9B 00 DO NOT JUST PASTE THE ABOVE ABS CODING TO YOUR ABS CODING.