ISO 9141-2. This protocol has an asynchronous serial data rate of 10.4 kbit/s. It is somewhat similar to RS-232; however, the signal levels are different, and communications happens on a single, bidirectional line without additional handshake signals. ISO 9141-2 is primarily used in Chrysler, European, and Asian vehicles.
- pin 7: K-line
- pin 15: L-line (optional)
- UART signaling
- K-line idles high, with a 510 ohm resistor to Vbatt
- The active/dominant state is driven low with an open-collector driver.
- Message length is Max 260Bytes. Data field MAX 255.
Another scheme
IC3, IC4 are Si 9241aey or Si9243aey, both can be used but pins are diffrent
Used for Volkswagen, Audi, Skoda, Seat. + opel bu only K-line