Defeating Start/Stop by software! (Free tutorial inside)

I remember the first time I drove a car with an automated start/stop function. At the first traffic lights, the engine stopped, and I got this burst of cold sweat: wtf did just happen?!

It took some time to get used to, and found myself disabling it with VCDS pretty quickly, until I got my Leon, where the system could no longer be disabled! It became my standard routine to just press the button as soon as I got in the car. But there had to be a way to defeat the system again!

I knew the answer had to be in the Driving Profiles settings. Driving Profiles have a Start/Stop enable function (going into Eco mode will light up the Start/Stop button and activate it again), so there had to be way to disable it from there.

After many tests (I've flashed > 3000 datasets to my gateway so far!), I focused on something else… and then I noticed: whenever I cylce through my profiles, I see a start/stop message on my screen! I took a deeper dive, and then I found: Offroad profile turns off the Start/Stop!

In the past I was always looking for the light on the Start/Stop button, to determine whether or not it was enabled… turns out I was looking in the wrong place!

So… how to get this working on your dataset?
Pretty straightforward! If you're allergic to technical stuff, please look away, and otherwise, grab your laptop and start playing around.

Let's start with a Skoda Octavia dataset (version M900), open it in 010 Editor, and parse it with my template (get it here: github.com/jilleb/mqb-fpa) :

Have a look in the output console (press Alt-3 if you don't see it):

This dataset has a control for "ESC System". In reality, this doesn't seem to change anything to the behavior of the ESP/ABS/ASR system.

When you scroll down, you will see the request values that are sent to the control module after the mode is selected:

Here you see, the request value to the module is "4" in offroad mode, and "2" in normal. These values, you will see in the Measurement Blocks in your control module:

In this screen, you will see the Requested/Specified value and the Actual value of the control module profile. When you press the button, gateway sends the request value to the control module, and you will see it as the Spec. value here. When the control module accepts the value, the actual value will change accordingly.

What to change?
Going back to this matrix of request values, we need to make changes in the red area:

You can find the values by looking at the green column and row names. First, let's find the "2" and "4" value for ESC System. We need to look at request_values_2(because the 4 is in the column with this name), and find the 9th entry there (because ESC System is the 9th entry):

Found on photo: 000200, 545404, F10000, 020203

Let's replace the "2" by a "4" as well, so the normal behavior sends an "Offroad" value. First, find it:

Found on photo: 50040400

Change it, and run the template again (press F5), the request value matrix will be updated with the new data:

Found on photo: 1000000, 000030000, 240790, 333333, 50200000 and others

That's it! Save the dataset with the Save script, flash it to your module, and now the Start/Stop will not engage anymore. The only change you will see on screen is in the Start/Stop information screen, where it will notify you that you're in Offroad mode. Your turbo will love that it will no longer be cut off from oil circulation when you're in a traffic jam ;-)

Word of caution:I have no idea what side effects this will cause. I've driven about 500km with this setting to "Offroad", and haven't had any issues. But I cannot guarantee that it won't make any other impact. Changing this setting is at your own risk!

Happy coding!