Hello together,

I fiddled together a tool which can patch a "multimap" solution into a MED9.1 Binary using the variable vkKraQu
https://github.com/EliasKotlyar/MED9.1-Multimap-Tool

What is vkKraQu?

In some MED9.1 Binaries(for example 1Q0907115C), you will find following tables:
LDRXN_0_A, LDRXN_1_A, LDRXN_2_A

Most of the tuners are just setting the same values for all the 3 Tables and there are a lot of myths about which table is getting used when.
After studying the code in ghidra, i found out that there is a ram variable called "vkKraQu" which stands for "Variantenkriterium für Kraftstoffqualität"(english"Variant Coding of Fuel Quality").
Its basically a var which decide which table to use. So if you set it to "0",  LDRXN_0_A will be used. If you set it to "1",  LDRXN_1_A will be used..etc
vkKraQu is getting assigned a value from EEPROM at each start of ECU, but can be changed in runtime.


How does it work?
My tool patches some function which is running every 20ms, and sets the vkKraQu to a certain value depending on cruise control status.

The source code is literally:

B_fgr is a variable which tells if cruise is enabled/disabled.

On which binaries does it work?
Its working currently only on 1Q0907115C, but there is a adaptation guide in the repository. I will happy accept any MR covering other binaries.

Which maps are influenced by vkKraQu?

At least on 1Q0907115C, its directly switches following maps:


How do i start?
1. First use the adaptation guide for your binary, and adjust the variables(see guide)
2. Change the map(s) <mapname>0_A to your needs (maps which will be used if cruise if off)
3. Change the map(s) <mapname>1_A to your needs (maps which will be used if cruise if on)
4. Have fun!

Disclaimler
As always i am not responsible for your adventures with my software. Binary changes always have some risk, and should be verified with Ghidra/IDA Pro afterwards before blindly applying to your ECU.

PS:
A cheapskate "mapswitch" might be possible using VCDS only. The vkKraQu is stored in EEPROM as a long-coding variable, however the label files of VCDS are not covering it as its not present in every MED9.1 Version.
If someone have the time, he can modify the label files to cover vkKraQu, and switch the maps without any modifications to the binary. However its not that convinient in comparison to cruise-control.

@prg:
First of all, it does not remove cruise control.

What it does: It does use cruise control as trigger to switch the maps.

What do you mean by usable? Any ideas on further improvement are appreciatet.

Sorry for the misunderstanding, but this is the whole idea of this project:

Following is a little example:
You have 2 map-sets, lets say a mapset A with "normal tune" and mapset B with "stage1".

You drive around with your normal tune on the highway using no cruise control. This will enable mapset A. As soon as you want to have some fun, you switch on cruise and you will get your mapset B activated which will give you a performance boost.

What would you recommend how it should work?

This is stupid, as is switching the map for changing power level - just use your right foot to press the throttle a different amount.
Switching is useful for different fuel, e.g. RON98 and RON102 or even VP MS109.

Use your imagination at least a tiny bit.
You can even do the mapswitching with only the brake and the accelerator pedal when the engine is turned off.
If you want to use the cruise control, then introduce some logic.
Simplest way with 2 maps is set when brake is active to go to one map and then res when brake is active to go to other map.
Maybe flash MIL to indicate it was switched.

There are also much better solutions with edge detection (button pressed/released) and other logic.
All without affecting the original function of the cruise control.

But like this it is just bad.

Okay, its just my habits, costs 2 NOPs but eliminate some potential issues. The chances are low but not zeroes 


Well i make this many years ago with me7 so i can miss some details and those for 4 map sets, its better to flashing with CEL i believe if you just want to enable/disable something

counter = 0; ticks, new var, should be 0 when initialised
b_flag = false; new var
b_brake
b_fgrSet ;set button

call instead of vkKraQu stock setting:


next, if you using CEL blinks there is some variable to blink CEL in stock, i didnt remeber how it names (stock CEL blinks when misfiring), lets say it b_MILblink

call where b_MILblink assigned


In this case counter is an overall time to b_MILblink is active and youve got to set counter multiplier in main routine to get 1 and 2 blinks
************

Tacho: (in case you have more than 1 set)

counter = 0; delay, new var, should be 0 when initialised
maxMaps = 3; maximum set which user can choose, new param
b_flag = false; new var
b_brake
b_fgrSet ;set button


nmot_can assignation call:



IIRC b_fgr is true when cruise is active, literally cruise with the ecu holding target speed not you 


But in general i agree with prj, just use your foot. Properly tuned IRL/IOP etc gives you all abilities for that, im using multimap few times in a years just when leave the car in service or giving it to gf 


*ps
As in idea based on DSG mode -> if (gwhpos == 12) || (gwhpos == 9)  { vkKraQu  = 1; } else { vkKraQu = 0;}  // if sport or tt mode
Or something similar with the ESP