Central Body Electronics (ZKE III)

The ZKE III system was introduced on the E38 in 1995 and subsequently used on the E39 and the E53. ZKE III is responsible for the control of various body electronics systems. Although there are some functional differences from model to model, the majority of the functions and systems are identical.

The ZKE III system is comprised of the General Module (GM III) which is connected to a network of peripheral modules all connected by a bus network. The Peripheral Bus (P-Bus) is responsible for transferring commands and information between various system components.

The modules on the P-Bus which are connected to the GM include:

• Driver's side door module (switchblock) PM-FT/SB
• Passenger door module (PM-BT)
• Sunroof module (SHD)
• Seat/mirror/steering column module PM-SM
  Fig 1: Identifying General Module (GM III)

  Courtesy of BMW OF NORTH AMERICA, INC.

The modules of the ZKE III system are networked together by the P-Bus to control the functions of the body electronics which include:

Systems controlled directly by the GM III 

• Windshield Wiping/Washing
• Automatic Interval Control (Rain Sensor)
• Headlight Washing
• Tailgate Wiping/Washing
• Interior Lighting
• Central Locking
• Keyless Entry
• Key Memory
• Power Trunk Release
• Electric Opening of Tailgate
• DWA Alarm System
• Servotronics
• Consumer Cut-off/sleep mode
• Diagnosis

Systems controlled by the Driver's Door Switch Block module 

• Power Windows
• Mirror Adjustment/Memory/Heating

Systems controlled by the Passenger's Door Module 

• Mirror Adjustment/Memory/Heating
• Power Windows

Systems controlled by the Sunroof Module (SHD) 

• Power Sunroof

Systems controlled by the Seat/Mirror/ Steering Column Memory Module 

• Seat Adjustment/Memory
• Steering Column Adjustment/Memory