RoB9

Maybe the link changed but updated it.

Here is the description if you just want to search:

For Audi A4 B9 2015-2020 A5 B9 A3 8V Q5 FY Car Automatic Stop Start Engine System Off Device Control Sensor Plug Accessories

Nikon1

I “coded” the *** out with the OBD Eleven about 2 years ago and it’s worked flawlessly ever since, even when I have turned the AC off — but I think the way the coding works on the OBD Eleven system is even when I have disabled the AC via the environmental control button, the ODB Eleven codes have the compressor running. Again, I Think but I’m not stating this as a fact. And using the OBD method does not turn the *** LED on.

Anyone who has coded this out — is my assumption correct t?

— John

Daaavid

I read somewhere on the other Audi forums that the coding has something to do with the climate control, so if you only have the fan running with AC OFF, it is enough to cause the vehicle to not satisfy start/stop parameters thus start/stop ceases to function. If the parameters are not met, (e.g. vehicle is still cold like in my video I posted), then start/stop will not work and will illuminate as such next to the gear indicator in the Virtual Cockpit/instrument cluster. The center control panel where the actual start/stop button is will still be unlit, with/without coding.

The aftermarket harness that is the item in this thread and video do not require coding, illuminates the start/stop button in the center control panel indicating it is off, and you can still reactivate start/stop if you wanted to via the button press. It's the reverse of the factory setting and is the most OEM way to do it without touching anything else on the vehicle.

Using the aftermarket harness is attractive to me because if I am idling in a parking lot with the A/C running and start/stop is running, the engine only turns on to run the A/C compressor to maintain my desired temperature and then the engine turns back off. With the OBD11 and VCDS coding, this is not possible because the climate control is on (fan is ON and/or AC is ON).

JLoft

I’m going to guess, but am fairly certain, that the control box closes the contact wires going to the switch for a moment a few seconds after power up. It’s just like pressing the button yourself, but the little box does it for you. Ingenious.

A guy on the internet has been selling a gadget like this for some domestic cars for a couple years. In the case of Chevy the stop/start won’t activate if you’ve have the hood open. So you put his box in the hood wiring. It pulses the hood open switch at start and then the start/stop won’t activate while you drive.

Nikon1

@Daaavid — For me, I don’t think I’d ever re-enable the start / stop. This is strictly my opinion, but for the (potential) gas savings versus the (potential) wear and tear on the starter from *** being on, it’s just not worth it.

Again — IMHO

— John

synergize

This looks like a very good solution to *** which I find to be asinine to begin with, plus it come with the two removal keys. Seems like a gift from the Audi gods.

RoB9

Its pretty easy and reversible.

OzRS5

AC is always on in Australia! I have an email into OBD11 awaiting a response.

synergize

Another nice feature as you say. I don't need the AC to always be on so not really a fan of the OBD11 solution. Looks like this is going to be a really good fix for ***...easy, inexpensive and from the video above an Audi part. The only negative is waiting 3 weeks for the part to arrive, and remembering to hit the *** switch, ha!

Yoshimura

There are 6 switches and only 5 wires so I would guess the module for the switches is connected using a CAN bus and the control box sent the proper message (*** switch pressed) a few seconds after power up.