General

General

Requirements for the OBD II System:
- Monitoring the efficiency of the catalytic converter (TWC).
- Detection of combustion misfiring.
- Monitoring of the tank ventilation system.
- Monitoring the tank system for leaks.
- Monitoring of the secondary air injection.
- Monitoring the adaptation limitation of the oxygen sensing system.
- Monitoring the oxygen sensors.
- Monitoring of other emission relevant components (former OBD I scope).
- Triggering the Malfunction Indicator Lamp (MIL or Check Engine) and storing faults in the memory.
- Protection against manipulation of control modules.
- Indication of monitoring readiness (Ready Code).
- Displaying the Diagnostic Trouble Code.
- Storing of operating parameters in the event of a fault (freeze frame).
- Functional checks of the OBD system (trip, warm-up cycle, driving cycle).
- Standardised control module tester (generic scan tool).
- Standardised read-out of operating data such as rpm, temperature, etc.

Ambient conditions
Three ambient (operating) conditions can be stored with each fault.

These can be:
- Relative charge
- Engine temperature
- Engine speed
- Intake air temperature
- Voltage supply
- Throttle valve angle
- Tank level
- Vehicle speed
- Change in nominal throttle valve angle
- Throttle position sensor lower limit
- Voltage of throttle position sensor in emergency air position
- Voltage of throttle position sensor at lower stop
- Voltage of pedal sensor
- Internal resistance of oxygen sensor after TWC
- Voltage of heater output stage of oxygen sensor after TWC
- Internal resistance of oxygen sensor ahead of TWC
- Voltage of heater output stage of oxygen sensor ahead of TWC
- Period of oxygen sensor signal
- TWC temperature (calculated)
- Engine compartment temperature
- Exhaust temperature ahead of TWC (calculated)
- Voltage of oxygen sensor after TWC
- Voltage of oxygen sensor ahead of TWC
- Air mass flow
- Linearised engine temperature
- Engine temperature substitute value
- Calculated actual torque
- Longitudinal acceleration of vehicle
- Actual gearshift
- Permitted indicated torque
- Indicated resulting nominal torque