An Onboard Diagnosis System (OBD) is a surveillance system that monitors parts of interest of the vehicle via sensors. The OBD system is supervising the vehicle via automatic test routines unnoticed of the driver. OBD is checking the plausibility of the data from the sensors. Is a malfunction detected, thus exceeding a defined limit value, the information about the error are stored in the error memory as trouble code or additionally are shown in the dashboard via MIL (Malfunction Indicator Lamp). For the off board evaluation of the OBD data, a connector plug and a communication protocol were developed. The OBD system was originally developed to monitor only exhaust relevant parts of vehicles. OBD was introduced in the early 1980´s in the United States in order to maintain the exhaust gas quality over the lifetime of the vehicle. Therefore OBD is used today as a synonym for exhaust surveillance, but in the meanwhile the OBD system is not only limited to exhaust relevant parts of vehicles. Today additionally safety relevant functions of vehicles are supervised by OBD systems. In the beginning every manufacturer had its own communication port and protocol. In 1988 the Society of Automotive Engineers (SAE) set a standard plug and a set of diagnostic test signals, today known as OBD1. This standard was the basis for the 1994 introduced OBD2 standard with extended function ability. In Europe the OBD2 guideline was modified and introduced as EU guideline 98/69 EC under the synonym EOBD in 2000. To expand the advantages of OBD on vehicles with diesel engine, the EU introduced the diesel OBD in 2003. But unfortunately the standardisation is limited to exhaust relevant functions, so diagnostic functions beyond exhaust gas are not subjected to any standardisation, therefore every manufacturer is using its own diagnostic protocol. So the major problem for OBD as a helpful system for roadworthiness in a broad application is the lack of a standard. With OBD in the PTI the operator becomes the possibility to take a close look behind the surface of the vehicle. Germany is the first country in Europe that uses the OBD system in the PTI for checking the exhaust gas system. OBD in a vehicle gives the operator more information in a shorter time, so it makes the work of the tester more effective. But this is just the first step. The example of exhaust gas test shows the potential of the OBD system in the PTI. Manufacturer and supplier recognized the advantages of a standardized communication port and protocol in the automotive sector. The rising complexity of automotive electronics and the rapidly increasing cross-linking, manufacturer and supplier began to use the OBD port for vehicle diagnosis beyond the exhaust gas system. Nowadays the rising complexity of automotive electronics makes vehicle diagnose indispensably, so the OBD interfaces are not only used for the off-board gas evaluation but also for checking the safety relevant systems of the vehicle. With modern diagnostic devices the complete system status of electronically controlled systems can be monitored e.g. airbags, brakes, steering. The OBD connector is the keyhole to enter the vehicle network in the automotive sector and helps to maintain the technical functionality of the vehicle. (Author/publisher) For the final report and other Workpackages of the AUTOFORE project see http://cita.weborigin.be/AUTOFORE%5FStudy/map.htm
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