Inspection and Maintenance - Decreasing Fuel Consumption and Exhaust Gas Emissions in Transportation - page 188

failure-code

16-pol OBD interface RS 232

exhaustion

Fig. 13.2 Control of heavy duty vehicles with ''free acceleration''

Table 13.2 Main OBD functions in a spark ignition engine
Continuous monitoring systems

Sporadically monitoring systems

Irregular operation of engine (misfire)
Mixture adaptation (self adjustment)
Other exhaust gas relevant components
CAN bus communication

Catalyst function
Catalyst heating
k sensor
Secondary air system
Exhaust gas refeeding
Tank ventilation system
Tank leak diagnosis

equipment and an external test device, which can be adapted to the motor vehicle
via an OBD interface (see Fig. 13.2 )[ 6 ].
After the connection with the interface, the test equipment automatically adjusts
itself to the data transfer system used by the engine control device. The stan-
dardized format is specified for the nomenclature of components and systems
which are obligatory for all manufacturers.

13.1.1 OBD in Vehicles with Spark Ignition Engine

Electronic systems and computer technology open novel possibilities for electronic
detection of errors in motor vehicles. Monitoring was first introduced in spark
ignition engine technology. Nowadays, OBD controls the function of all exhaust
gas components with a comprehensive monitoring system (see Table 13.2 )[ 7 ].
Because of the multiplicity of information, the signals of individual elements
are transferred via a CAN bus to the motor management system.