Audi A5 8W Auto Hold retrofit

In order to have your AutoHold retrofit, you will need to buy Auto Hold switch [4M1927143] and wiring harness. I bought my switch from and the harness from Aliexpress. You can also make your own harness, of course.

Once you have your parts ready, you can start running wires and connecting.

Your AH switch [E540] has 4 pins which needs to connect to;

1- Front Electronics Unit [J519] : B-31
2- Handbrake button [E540] : PIN-6 (GROUND)
3- Front Electronics Unit : [J519] A-17
4- Handbrake button [E540] : PIN-5 (+)

Cabling will look like this

Coding is a bit tricky. Use VCDS to code like below;
– Module 9 Byte 15 Bit 6 is set from 0 to 1
– Module 3 Byte 18 Bit 6 is set from 0 to 1
– Module 3 Byte 30 Bit 1 is set from 0 to 1
If your car doesn’t have Adaptive Cruise Control, these will work just fine. With ACC, I used ODIS-E to do the coding, since VCDS cannot calculate binary and update checksum correctly. If you are new to ODIS-E, you will need to have au49 workspace and its files in order to code properly.

Here is the result