Modulated, Momentary, Constant B- as Input/Output

The input signal of control module 1 is an output signal of control module 2.

Control module 2 through activation of its internal transistor provides a ground input for control module 1.

Fig 1: Identifying Modulated, Momentary, Constant B- As Input/Output Function

Courtesy of BMW OF NORTH AMERICA, INC.

The input signal at control module 1 is either a momentary/constant signal (i.e torque convertor signal from TCM to DME) or a modulated signal (i.e. vehicle speed signal ASC to DME).

Fig 2: Identifying Wheel Speed Signal And Output Pulse

Courtesy of BMW OF NORTH AMERICA, INC.

Typical Application of Modulated, Momentary, Constant B- as Input/Output Signal: 

• A/C KO Signal.
• Speed Signal From ABS/ASC.
• TI/TD Output Signal From DME.