Operation CHARM: Car repair manuals for everyone.

Functional Description



Functional Description:

General Block Diagram:




System Design and Function:

The individual components of the microprocessor-controlled ABS system correspond to those of the conventional 4-channel ABS system (Bayreuth).

Difference between "Bayreuth"- and microprocessor-controlled ABS control unit:

The "Bayreuth" ABS control unit can be identified by the green adhesive label on the front end of the control unit housing and has the BMW No.1 158 958 or 1 160 046 (US version).

The microprocessor-controlled ABS control unit can be identified by the orange adhesive label on the front end of the control unit housing and has the BMW No.1 160 410 or 1 160 411 (US version).

Compared to the previous ABS control unit, the scope of functions of the microprocessor-control led ABS control unit has been extended by the self-diagnosis functions.

The microprocessor-controlled ABS control unit is connected to the diagnostic bus of the vehicle and can be addressed by means of the BMW DIAGNOSTIC SYSTEM.

Indication Logic of the ABS Lamp:

After ignition ON (terminal 15), the ABS lamp is activated for 2 seconds and then goes out (lamp check).

When the ABS control unit detects a defect, the defect code is stored and the ABS lamp activated (steady light).

If the defect no longer exists after the next system start (ignition OFF/ON), the ABS lamp goes out after the lamp check, however, the defect code remains stored in the defect code memory.

The ABS lamp lights constantly during data exchange between the ABS control unit and the BMW DIAGNOSTIC SYSTEM (diagnostic mode in the workshop). The ABS lamp goes out on completion of communication - after return to overview of control units -.