Adaptive Cruise Control nachrüsten

Moin, dann habe ich es endlich geschafft ACC für meinen Audi A4 8k 2008 2.0 TDI CAGA mit JJG Getriebe nachzurüsten 🙂 War ein langer Kampf wegen anderer Getriebeübersetzung als der Audi A4 8k der ACC hat (ab 11.2008 glaube ich…). Unten gibt die Anleitung ohne Getriebeaustausch 🙂 Aber auf Englisch weil Deutsch nicht meine Muttersprache ist und vielleicht haben auch andere Interesse daran…

As mentioned above, I wanted to retrofit ACC. After doing everything according to instructions in this thread etc. and flashing the ECU with new software, the gear indicator in the instrument panel disappeared and ACC was disabled in 5th and 6th gear (where you would really need it). After a lot of research, I found out that the gear ratio was changed before the version with ACC was released. KXP is the number of the new manual gearbox with longer ratio I believe… In some Italian forums, they have managed to retrofit this, but only after changing the gear box. I have finally managed to do it with only changing the ECU software 🙂 It took A LOT of reverse engineering and trial and error editing the flash file.

My original configuration:
Audi A4 Avant 8k 2008 2.0 TDI CAGA 143PS and JJG manual gearbox – First time registered 01.06.2008.
ECU HW: 03L 906 022B SW: 03L906022B version 9970

(No responsibility taken if this does not work on your car, and if you really want to be 100% sure not to get IMMO problems or similar, you may consider to extract the ECU and backup the complete SW with internal flash and EEPROM in bootmode.) However I did it according to below without any issues… NB! Important to ensure stabile voltage during flashing! E.g. connected to power source or (not optimal) good status of battery….

Step by step guide:
After having done everything according to the standard ACC retrofit guides, do the following to adapt gear ratio.

1. Read out the Internal flash data of your ECU SW xxxB, 2048 kb. You can e.g. use Galletto FGtech v54 via OBD. Bootmode was not required for me.
Flash the ECU to a SW which supports ACC. SW xxxB does not support it. I used MJ version, and flashed with VAG CAN Professional. Flash files can be downloaded via e.g. erWin in the frf format.
New SW: 03L 906 022MJ version 9335

2. Read out the Internal flash data of your ECU SW xxxMJ, 2048 kb. You can e.g. use Galletto FGtech v54 via OBD. Bootmode was not required for me.

3. Using a hex editor (or even better tools such as WinOLS) update the area which contains the gear ratio for the instrument panel.
In my flash it was found at address:

a. 1A0ED2 to 1A0EE8 – Axis transmission ratio between engine speed and vehicle speed:
My old B SW (new values for your MJ file):
Decimal, 16 bit, unsigned:
2240 2560 2624 3264 3328 4224 4480 6144 7040 10240 11520 19200
Hex, 16 bit:
08C0 0A00 0A40 0CC0 0D00 1080 1180 1800 1B80 2800 2D00 4B00

My new MJ SW (values to be replaced with values above from B SW):
Decimal, 16 bit, unsigned:
2061 2432 2534 2982 3136 3878 4147 5478 6016 8934 10227 16218
Hex, 16 bit:
080D 0980 09E6 0BA6 0C40 0F26 1033 1566 1780 22E6 27F3 3F5A

b. 1A0ED2 to 1A0EE8 – Axis transmission ratio between engine speed and vehicle speed,2:
My old B SW (new values for your MJ file):
Decimal, 16 bit, unsigned:
2176 2611 2662 3264 3328 4096 4224 6144 6272 10240 10880 19200
Hex, 16 bit:
0880 0A33 0A66 0CC0 0D00 1000 1080 1800 1880 2800 2A80 4B00

My new MJ SW (values to be replaced with values above from B SW):
Decimal, 16 bit, unsigned:
2035 2458 2509 3021 3098 3942 4083 5606 5888 9267 9907 16922
Hex, 16 bit:
07F3 099A 09CD 0BCD 0C1A 0F66 0FF3 15E6 1700 2433 26B3 421A

If you have the same values in your B and MJ read flash files all should be good! I have identified this using various flash files read for SW such as B (not ACC suppport), MJ (ACC support), JM (ACC support), and changing MJ vs B differences gradually.

c. 1F9054 to 1F9078 – Min, max and change of gear ratio between engine speed and vehicle speed:
If you investigate DAMOS files it seems to be second area which also represent gear ratio, however it is not required to get the gear indicator working in the instrument panel.
“Parameter für maximales Übersetzungsverhältnis Gang 1 (1x1)”
„Parameter für minimales Übersetzungsverhältnis Gang 1 (1x1)“
„Parameter für Übersetzungsverhältnis vom 1. in den 2. Gang (1x1) „
„Parameter für maximales Übersetzungsverhältnis Gang 2 (1x1) „
„…“
My old B SW (new values for your MJ file):
Decimal, 16 bit, unsigned:
1260 0 1260 2000 1260 2000 2800 2000 2800 3800 2800 3800 4700 3800 4700 32767 4700 1000 1000
Hex, 16 bit:
04EC 0000 04EC 07D0 04EC 07D0 0AF0 07D0 0AF0 0ED8 0AF0 0ED8 125C 0ED8 125C 7FFF 125C 03E8 03E8

My new MJ SW (values to be replaced with values above from B SW):
Decimal, 16 bit, unsigned:
1200 0 1200 2000 1200 2000 3000 2000 3000 3900 3000 3900 4900 3900 4900 30000 4900 1000 1000
Hex, 16 bit:
04B0 0000 04B0 07D0 04B0 07D0 0BB8 07D0 0BB8 0F3C 0BB8 0F3C 1324 0F3C 1324 7530 1324 03E8 03E8

d. Save/export the bin-file.

5. Flash the file to the ECU using e.g. Galletto FGtech v54 via OBD. NB! The new checksum needs to be correctly updated using your editor (e.g. WinOls” or flashing software (e.g. Galletto).