W-Line

Protocol called W-line is used for immobiliser communication between Body Control Module and ECU in SMARTRA-equipped vehicles.

Overview

Typically, you would now see somewhere around 200 pages of big words and lengthy paragraphs that would probably only increase your confusion and not generate any new knowledge.

However, this is not a ISO specification and I'm not trying to sell you a $1500 device either so I'll just make it simple; W-Line is K-Line. At least on the physical side. The data layer is documented in SMARTRA Protocol and physical layer documentation is in the K-Line article already, so there is no point duplicating that.

I'll only share a tip: LIN bus also uses the same physical layer. I had a "UART to LIN module" from asian marketplace laying around and used it for my W-line escapades (combined with the EEPROM programmer, CH134a, running in TTL<>USB mode. I recommend getting the ch134a, it's basically free.)