The KWP-2000 Protocol, commonly named as KWP2000, is a diagnostic Communication protocol for On-Board vehicle Diagnostics applied for OEM. There are two primary International Standardized documents such as ISO 9141, ISO 14230 covered for performing the OBD Communications on K-line between Tester and vehicle.ISO 14230 specifies common requirements of diagnostic services which allow a tester to control diagnostic functions in an on-vehicle Electronic Control Unit.
The ISO 9141 is a bidirectional serial communication detail which specifies K-line is used for communication and initialization; the L-line (optional) is used for initialization only. The Special cases are node-to-node-connection, this means there is only one ECU on the line which also can be a bus converter. ISO 14230-2 specifies the Data link layer and ISO 14230-3 includes all the definitions which are necessary to implement the Diagnostics services as per KWP-2000 Protocol
The Keyword Protocol physical layer may be used as a multi-user bus system, it is necessary to maintain or manage arbitration and bus management system. In below figure described the Vehicle Diagnostics architecture of KWP-2000 Protocol which specifies communication among Tester and ECU network with Gateway or Without Gateway access.
In KWP-2000 Protocol there is no continuous communication must be initialized without being first requested by the tester which means that Wake-Up at 5 baud per second. The 5 Baud address byte is transferred from the Tester on K-line and on L-line. After sending the 5 baud address byte the tester will maintain L-Line on the High level. After the Wake-up procedure, all ECU’s are initialized shall use a baud rate of 10,400 Baud for initialization and Communication.