Decode a Continental MK100 ABS/ESP long coding byte by byte, check its mirror bytes, and re-stamp a donor coding for another VIN. Runs in your browser — nothing is uploaded.
Detection is built from patterns across real files. If this tool misread your dump — or read it correctly and you are happy to help — sending us the file makes the next read better. Entirely optional, and nothing is sent unless you fill this in and press the button.
The Continental MK100 is the ABS/ESP unit across the MQB platform — Golf 7 and 7.5, Passat B8, Tiguan, T-Roc, Arteon, Octavia, Leon, A3 8V and the rest — and its long coding is far longer and less readable than the MK60EC1 it replaced. This tool takes the coding as you read it out and tells you what every byte says: which brake discs, which rear suspension, whether Start/Stop and hill hold are coded, how the ESP button is set up, which TPMS variant the car has.
Before it interprets anything it proves the coding is intact. Certain bytes are bit mirrors of earlier ones — byte 15 repeats byte 0 with its bits reversed, byte 16 repeats byte 2, and so on — so a coding that was misread or mistyped fails arithmetic that cannot be argued with. Seven more bytes carry VIN characters, each as that character's code plus a fixed offset, and the tool reads them back out as the VIN fragment the module is storing. Those two checks together also identify which coding layout you have, so you do not have to know whether the car is a 3Q0, an 8V0, an 8S0 or a 2Q0 before you start.
Because the VIN is inside the coding, a coding lifted from an identical car is refused by the module. The VIN-adapt tab fixes exactly that: paste the donor coding and the target VIN, and the VIN bytes are re-stamped and the mirror bytes recomputed. This is what makes a used MK100 pump take a coding. The equipment bytes are still the donor's, so the tool says so plainly — if the donor had different brakes or suspension, decode the result and correct those bytes too.
The byte layout is arithmetic and the tool verifies it in front of you. The equipment meanings are a different kind of knowledge: they are transcribed from the community MK100 ABS Coding spreadsheet compiled on the Ross-Tech forums, and that sheet grades its own confidence byte by byte and bit by bit. Rather than hiding this behind a disclaimer, every line carries its grade — tested, unconfirmed or unknown — and the bytes nobody has worked out are left blank instead of filled in with a plausible guess. Nothing on the page is invented.
Everything happens locally in your browser with no network request of any kind, so the coding and VIN you paste never leave the machine. The tool produces a coding string; it does not talk to the car. ABS and ESP are safety systems — save the original coding before you write anything, and confirm the car brakes properly and the ESP lamp goes out before it leaves.