The following chapters provide an overview of diagnostic systems in vehicles. You should end up losing their shyness in front of technical terms as ODX, OTX, MVCI, UDS, KWP 2000, ISOTP, CAN, FlexRay, LIN, and many others. We want to facilitate you to your own path through the jungle of ASAM, ISO, SAE and company standards.

Diagnosesysteme im Automobil

To make driving safer, more pleasant and cleaner, more and more electronic systems are used. The diagnosis of such complex systems is thus an increasingly greater challenge.

If you look at the projected growth of the automotive electronics look across all markets, it is seen that in countries where already a high penetration rate of electronic components there is still a growth of 30 - 50% in the coming years is forecast. While in markets where the penetration rate is still significantly lower growth rates are expected to sometimes over 100%, see Fig.

Veränderung in der Automobil Industrie - und Marktvolumen Wachstum in der Automobil Elektronik

The driving elements are the competitive and cost pressures and the desire, the car more individual adapt to the customer. Will play increasing comfort and safety requirements and the need to conserve natural resources and reduce the emissions of a major role. Also influence new markets and new customer groups, social development and a package of legislative constraints to sustainable development.

The electrical / electronics proves to be more and more as the key technology. It is assumed that accounts in the near future about a third of production costs of a vehicle on the electronics.

The functionality is increasingly realized in this software. Typically today, new functions are distributed across multiple controllers, so that the degree of crosslinking between the individual electronic components plays an increasingly important role.

If we look at today is a modern middle-class vehicle, as illustrated, then we have even the basic facilities and even in the fully equipped an entire range of control devices that move the vehicle to drive: Here are basic systems such as engine control, ABS, ESP related etc. , convenience electronics such as lights and door control, parking assistance systems, driver assistance systems like adaptive cruise control, lane change assistance, infotainment systems such as radio, navigation system, car phone, and much more.

This is all linked by a number of bus systems. This is necessary as are designed for a different bus systems for different tasks, since one to the other individual functions for security reasons separated from each other and would like simply because none of today's existing bus system alone is able to provide the bandwidth needs of the entire bus communication.

German mid-size vehicle (2007)

The following are the main aspects of the current state and development of the electronics are listed in Vehicle:

• Up to 80 control units, decreasing tendency ▼
• More than 1000 functions ascending trend ▲
• > 100 MB disk space, 13% of production value, rising trend ▲
• High degree of networking between the control units
• Up to 3 km line length
• Heute bis zu 5 verschiedene bus system (K-Line, CAN, LIN, MOST, FlexRay) Tendenz sinkend ▼
• A total of up to 20 buses and sub-buses
• Bus load partially in the border area

Today in modern luxury vehicles used over 80 controllers will increase no longer safe in the future to this extent. They will try to get along with higher integration rather something less. The set of functions will increase but also the amount of software. The degree of crosslinking between the control units will also increase. Crosslinking degree, meaning more data sharing, certainly not in terms of more bus systems. On the contrary, it is more likely to try to reduce the use of more powerful systems, the amount of bus systems. However, the bus load will also remain in the border area.

Challenge of increasing complexity at the example of an error cloud

The increasing complexity of these systems makes the most noticeable when something is not working as it should be, as illustrated. A car manufacturer, for example, reported the following: if fails in one of its vehicles a pin connector port on the gateway, then this is recognized by many control units, for all control devices monitor the bus communication. It will then be generated for only one cause of 38 errors in 5 control units. An employee of the workshop is also overwhelmed to find the right solution here.

Increasing complexity - Solutions

In contrast, refers to the off-board communication, the communication between the systems with a system outside of the vehicle, called the tester. Testers are available for the workshop, production, application, development or even for the TÜV. Illustrated in the figure above basic structure has now been established in most vehicles: the different bus systems in the vehicle through a central gateway connected to which and the diagnostic bus is connected.