Retrofits and CAN Bus

[Morten88]

I’m in the process of retrofitting the TPMS sensor and Audi side assist in an Audi A3 8V. The user manual states that side assist should be connected to the CAN bus extended in the red connector behind the steering wheel, and TPMS should be connected to the CAN bus extended in the black connector in the A pillar on the driver's side.
Is it possible to splice both cables together to the CAN bus behind the steering wheel? Can two cables be connected together in the same splice?

 

[strtnz]

In theory it's possible but if that were the case I'd imagine Audi would just use one in the first place and save the expense of a second one. I'd assume they'll be looking for different I/O signal voltages. It's risky if nobody knows for sure that you can.

 

[FPSUsername]

Side assist radars work if you connect them to the extended bus (pin 7/17) via the gateway. Use the gateway extension harness from AliExpress and connect them to the gray bus (there's blue and green as well).
Unfortunately, they didn't extend the powertrain bus (pin 6/16), people usually extend that bus from the foot rest pedal area.

You can have “tails” hanging around, CAN bus is not that critical that length must be matched, and it doesn't cause much reflection having the tail (extension hanging lose).