Design and Implementation of Unified Diagnostic Service Protocol

Abstract- Modern vehicles use the Electronics Control Unit (ECU) to control and monitor all the activities within the vehicle. The number of ECUs are increasing as the complexity of vehicles increases. All the ECUs present in the vehicles are communicated with each other via CAN protocol. Any malfunction in the ECU or abnormal behaviour of ECU is detected or understood by diagnostic services. CAN Protocol does not have advanced features like Diagnostic. The CAN protocol covers only the Physical and Data link layer of the OSI model. There is a need for a standardised diagnostic protocol which can use CAN as underlying technology. Standardised diagnostic protocols used in the automotive domain are On Board Diagnostics (OBD) and Unified Diagnostic services (UDS). UDS protocol is defined under the ISO 14229 standard and provides a standardized framework for in-vehicle communication and fault diagnosis. This project focuses on the design and implementation of the UDS protocol on an embedded system using STM32F407 microcontrollers. The project involves developing a diagnostic communication system between Electronic Control Units (ECUs) Light Control Module (LCM) and Tester tool connected over a CAN bus. Keywords- Unified Diagnostic Services (UDS), ISO 14229, Electronic Control Unit (ECU), Body Control Module (BCM), Light Control Module (LCM), Controller Area Network (CAN), Diagnostic Trouble Code (DTC), Routine Control Identifier (RID), Data Identifier (DID), ISO-TP (Transport Protocol)