Sorry for digging up this older thread, but this is something I’d like to know too! I have a '98 Passat and have been looking into k-line and kw1281 (sometimes called kwp1281), too bad that Volkswagen only published so little about it, even though it was standardized as SAE J2818 (that standard specification can be requested, for a fee, but is apparently quite useless).
I haven’t ‘observed’ myself that it’s actually kw1281 that’s used on my car, wouldn’t know how to (except for using VCDS, but I don’t have it). But all documentation I find online mentions that protocol for that model and year.
A few days ago I found this, however: kw1281test: A Free VDS-Pro / VagTacho Alternative | TDIClub Forums
Seems to be the most advanced reverse engineering effort, with quite some results. Something you can also do is extracting the skc (secure key code, needed when you want to ‘learn’ a new cluster, key, … to the ECU, so the ‘immobilizer’ doesn’t get activated) from the eeprom, not even VCDS/VagCom does that. He used the info on the link in the previous post for his development, but also other people’s reverse engineering efforts, and found out a lot himself by sniffing etc.
I’m tempted to try it, need to order a KKL cable though.
Maybe it’s useful… I wonder if somehow it can request ‘live’ data and pass it to Realdash, for example?
All these protocols, pin outs, … are quite confusing, also I’m definitely not a developer myself. So maybe it’s an unrealistic idea, still wanted to ‘pitch’ it though.
BTW, i don’t know if it’s relevant, but the OBD2 protocol works fine for that car, rpm, speed, … data are displayed nicely in Realdash. The shelll (monitor) reported protocol 3, iso9141-2 (5 baud init, 10.4 kbaud). If i’m not mistaken, the 5 baud init is specific to kw1281?. Screenshot in another topic : Beginner questions - #4 by berre