System diagnosis, function - GF00.30-P-0001T

MODELS 211.0 /2 /6 up to 31.5.05 

System diagnosis 

Fault monitoring and localization during the journey is performed through the system diagnosis integrated in the central gateway control unit (N93).

The software of the system diagnosis is composed of:

• Onboard knowledge base
• Evaluation software (diagnosis algorithm)

When en route, all control units in the CAN class B and CAN class C transmit fault codes and supplemental information to the central gateway control unit (N93). Using the information in the onboard knowledge base, the evaluation software determines which components are faulty.

Function requirements: 

• Circ. 15 ON
• In order to output the faults, STAR DIAGNOSIS must be connected via the CAN diagnosis line (CAN-D) to the connector of the data link connector (X11/4).

Evaluation software 

The system diagnosis is based on the fault codes and supplemental information from the individual CAN class B and CAN class C control units. If a control unit detects a fault, the corresponding fault code is transmitted to the central gateway control unit (N93). In addition to this the control units transmit further supplemental information, which is used by the central gateway control unit (N93) for evaluation purposes.

The evaluation software can use the transmitted fault codes and supplemental information to categorize each electrical path:

• Path faulty: all components in this path are suspect.
• Path free of faults: all components in this path are OK.

The system diagnosis evaluation software can use this information to limit the number of faulty components.

Design and content of onboard knowledge base 

The onboard knowledge base describes the interrelationships between the fault codes, supplemental information and faulty components.

The different variants, such as variants in special equipment, national versions and functions, are stored in this onboard knowledge base and activated as appropriate for the specific vehicle.

Programming of onboard knowledge base 

The onboard knowledge base is programmed in the central gateway control unit (N93) during assembly at the plant.

In certain cases, it is necessary that the control unit be programmed in the workshop:

• After failure of the central gateway control unit (N93)
• When installing a new version of a CAN class B or CAN class C control unit that requires an update to the onboard knowledge base.

Output using STAR DIAGNOSIS 

The results of system diagnosis are read out and displayed under the "CGW" menu option.

The following information is displayed for each diagnosis result:

• Control unit version
• Actual values
• Control unit adaptations
• Complete list of conducted tests
• Complete list of fault codes

Inspection instructions not yet resolved can be listed for the purpose of improving diagnosis result.

Starting at the faulty components it is possible to branch off into the further test operations.

Additional functions:

• ATA alarm sources

  The system diagnosis stores fault symptoms from the antitheft alarm system (ATA) (with code (551) Anti-theft alarm system (ATA).

  These error images provide indications on the cause of a triggered alarm.

• Actual and specified configuration of the control units on CAN class B and on CAN class C. A comparison of the specified and actual configurations for the control units will indicate whether they are supposed to be installed and whether they are active in the CAN data bus.

	Central gateway control unit, location/task		GF00.19-P-4100T
	Data link connector, location/task/design/function		GF54.22-P-2100T