International Research Journal of Engineering and Technology (IRJET) e-ISSN: 2395-0056 Volume: 04 Issue: 07 | July -2017 www.irjet.net p-ISSN: 2395-0072 © 2017, IRJET | Impact Factor value: 5.181 | ISO 9001:2008 Certified Journal | Page 708 Implementation and Validation of K Line (ISO 9141) Protocol for Diagnostic Application Gauri Mahajan 1 , Mr. S.K.Parchandekar 2 , Mr. Mohammad Tahir 3 1,2 Department of Electronics Engineering Walchand college of Engineering, Sangli, Maharashtra, India 3 Project Manager , Tata Consultancy Services, Pune, Maharashtra, India --------------------------------------------------------------------------***----------------------------------------------------------------------- Abstract: There is requirement for setting up the interchange of digital information between on-board emission-related Electronic Control Units (ECUs) of road vehicles and the SAE OBD II scan tool as specified in SAE J1978. This communication is established in order to facilitate inspection, test diagnosis and adjustment of vehicle systems and ECUs. OBD II uses various protocols, of which K line is mainly used for diagnostics purpose. K line Transmission is based on UART signaling and Communication uses Request Response Pattern. This protocol is in use but components used to design K line transceiver have become absolute these days. So there is need to come up with new solution for K line transceiver which will satisfy all existing requirements and have life of at least 10 years ahead. Keywords: K-Line, On Board Diagnostic (OBD), L-Line I.INTRODUCTION On Board Diagnostic II: The solution to reduce emissions is development of good testing system of vehicles. On Board Diagnostic (OBD) is a system, introduced by the ―California Air Resources Board‖. OBD systems are incorporated in computers to monitor vehicles components which may affect emissions when they are malfunctioning. OBD systems provide access to users to monitor various key components of vehicle. These systems always detect malfunction. The OBDII (On-Board Diagnostics II) system ensures correct operation of the vehicleǯs emission control system during its lifetime by monitoring components for deterioration and malfunction. The output of the OBD system is malfunction indicator lamp ȋM)LȌ, also known as Dzcheck enginedz lamp. When fault is detected, MIL is illuminated and diagnostic trouble code (DTC) is stored. A freeze frame, containing diagnostic data taken from that moment, is also stored. A diagnostic tester (scan tool) is required to obtain and display the diagnostic information stored via serial diagnostic interface. The information can be read using one of the following 4 legislated data link layer protocols: SAE J1850 (ISO 11519-4) ISO 9141-2(K-Line) ISO 14230-4 (KWP 2000 – Keyword Protocol) ISO 15765-4 (CAN Diagnostics) K Line: The K-Line is suitable for both on-board and off- board diagnostics. K-Line is a bidirectional line. It is used during initialization to convey address information from the diagnostic tester to vehicle ECUs, simultaneously with the line-L. Line-L is a unidirectional line and used only during initialization to convey address information from the diagnostic tester to vehicle ECUs, simultaneously with the K line. At all other times it should remain idle in the logic Dzͳdz state. After conveying the address, the K line is used to convey bidirectional data between vehicle ECUs and the diagnostic tester to complete initialization. After initialization, it is used to convey request messages from the diagnostic tester to vehicle ECUs and response messages from the vehicle ECUs to the diagnostic tester. Specifications: 1. Specifies Physical and Link layers 2. Bidirectional bus, communicating over 1 wire (the K Line)