Central Control Module: Description and Operation

Central Body Electronics (ZKE):

Notes:

This section describes the ZKE system in general. If a defect occurs only in a part system of the central body electronics (ZKE), then follow the diagnostic procedure for the corresponding part system.

- Windscreen wiper control defective.
Testing and Inspection
- Power windows defective.
Testing and Inspection
- Sunroof defective.
[1][2]Component Tests and General Diagnostics
- Central locking system defective.
Testing and Inspection
- Door lock heating defective.
Testing and Inspection
- Headlight washer system defective.
Testing and Inspection
- Windscreen wiper pressure control defective.
Testing and Inspection
- Interior lights defective.
Testing and Inspection
Functional Description

Components of the Central Body Electronics (ZKE)

General module (GM): Controls and monitors all functions.

Relay module (RM): Contains the relays for power windows, sunroof, door lock heating, interior lights, central locking system and windscreen wipers.

Electronic power fuse: Fuse protection of working circuits.

Changeover relay intensive wash/wash pump: If intensive wash feature is installed.

ADV module (ADM): Relay for windscreen wiper pressure control.

SRA module (SRM): Relay for headlight washer system.

Central Body Electronics (ZKE) Part Systems:

The general module controls the functional sequence of the following systems:

- Windscreen wiper and washer system
- Headlight washer system (SA)
- Windscreen wiper pressure control (SA)
- Interior lights
- Door lock heating (SA)
- Central locking system
- Power windows (SA)
- Sunroof (SA)

The systems marked with "SA" are optional extras. Detection of which part systems are installed in the vehicle takes place automatically - see "Automatic detection of optional extras" at the end of this functional description.

General Module Variants:

A differentiation must be made between the following main variants:

1. General module for 5 and 7 Series up to model year '91:

- Automatic strike feature for power windows only on driver's door.
- Central locking system with blocking of ZV motor drives when "vehicle in arrest mode"

2. General module for 5 Series without power windows and sunroof up to model year '91:

- General module without connector C (26-pin, white)
- Central locking system with blocking of ZV motor drives when "vehicle in arrest mode"

3. General module for 7 Series as of model year '92:

- Automatic strike feature for power windows in "open" direction on all windows ("close" direction only on driver's door).
- Central locking system with blocking of ZV motor drives when "vehicle in arrest mode"

This general module replaces the variant "1". However, it must not be installed in the 5 Series as of model year '92 (modified ZV system)!

4. General module for 5 Series as of model year '92:

- Automatic strike feature for power windows in "open" direction on all windows ("close" direction only on driver's door).
- ZV system with uncoupling of ZV motor drives when "vehicle in arrest mode" (ZV system of E36 Series)

5. General module for 5 Series without power windows and sunroof as of model year '92:

- General module without connector C (26-pin, white)
- ZV system with uncoupling of ZV motor drives when "vehicle in arrest mode"

Electronic Power Fuse:



General block diagram: Voltage supply of general module and electronic power fuse.

The power circuits for the door lock heating and motor drives of the power windows, sunroof and central locking system are protected by the electronic power fuse.

It consists of the following components:

General module (1) with measuring circuit (2): Constant circuit measurement. If the current exceeds certain values, the external fuse relay is deactivated.

Fuse relay (3): External relay which is switched by the general module. The relay switches battery voltage to the working circuits in the relay module.

Fuse link (4): Additional fuse protection (30 A) of the working circuits and of the measuring circuit in the general module should the protection (fuse) relay (3) not switch reliably.

Function:

The general module deactivates the fuse protection relay when a short or overloading occurs in the area of the connected systems. The relay switches on again automatically after 60 sec. It is switched off again if the fault has still not been rectified. Automatic re-activation takes place 6 times in succession. The relay is always switched on again every time the ignition is switched off/on (terminal 15).

Defect Detection in the Relay Module:

Diagnostic Links:

In addition to the connection to the engine, links are also provided from the load circuits in the relay module to the general module. These lines serve as diagnostic links. They are used to monitor the relays for defects. The monitoring principle is as follows:

- Relay in rest position (not activated). The diagnostic link is connected to ground.
- Relay activated. B+ is switched via the diagnostic link to the general module.

The general module evaluates the signals from the diagnostic links and can detect the following defects:

- Relay does not pick up
- Relay sticking
- Ground line interrupted
- Diagnostic link interrupted

After detection of a defect, its defect code is stored in the defect code memory.

External Relays:

In addition to the relays in the relay module, the following external relays are also monitored for defects via the diagnostic links:
- ADV relay in the ADV module (ADV = Windscreen wiper pressure control)
- SRA relay in the SRA module (SRA = Headlight washer system)

General Schematic:




The general schematic shows the internal design of the relay module.

Abbreviations:

TSH Door lock heating
WS Windscreen wiper motor
IB Interior lights
ZV Central locking system
FH Power windows
SHD Sunroof
GM General module
RM Relay module

Diagnostic links:

DSH Diagnosis door lock heating
DWZS Diagnosis windscreen wiper motor and relay for central arrest
DZV Diagnosis central locking system
DFHA Diagnosis power windows - open direction
DFHZ Diagnosis power windows - close direction

Removal of the General Module:

The battery power supply for the general module (GM electronics) is routed via the relay module. From the protection fuse via relay module Pin B15 and Pin B5 to the general module connector A Pin 1.

The power supply to the general module is interrupted when the relay module is removed.

This ensures short-circuits cannot occur on the open lines at the general module.

Automatic Detection of Optional Extras:

Explanation:

After the supply voltage has been applied (terminal 30 at Pin A1), the ZKE general module checks whether all diagnostic links are connected to ground. If the input is open, the corresponding part system is detected as not installed.

Systems which are not installed are not included within the functional sequences in the general module.

The part systems detected by the general module can be monitored via the BMW Diagnostic System.

Defects:

If the general module is installed with the vehicle battery connected, undefined contacting when plugging in the module can result in an input being detected as open although the system is installed in the vehicle.

If a system is installed in the vehicle but not detected by the general module, disconnect the vehicle battery for at least 5 seconds.

If the system is still detected as "not installed" after reconnecting the vehicle battery (and reselecting ZKE!), the following defects may apply:

- Diagnostic link to relay interrupted
- Ground line to relay interrupted
- Relay sticking