2001 BMW 530i Operation

59
Central Body Electronics ZKE III
System Components
- with Principle of Operation
Manual Operation:The manual adjustments of the seat, mirrors and steering column are
carried out with the respective switches as with the previous systems.
The mirror adjustment switch is located in the driver’s switch block. The mirror operation
input is a digital signal that is processed by each respective module for mirror positioning.
Memory Storage: The parameters for storing memory positions are are as follows:
• With the transmission range
selector in “P” and the mirror
change over switched to the left,
switch the ignition on and press
the “M” on the memory switch.
• The memory indicator lamp swi-
tches on for 7 seconds.
• Press one of the three position
switches (1, 2 or 3) within the 7
second memory period.
• The current positions of the mir-
rors, seat and steering column
are stored for recall.
The positions of the mirrors are stored in the respective door
modules based on the position of the feedback potentiome-
ters. The positions of the seat and steering column are stored
in the seat module, based on the ripple count.
Recalling a memory position setting is possible by either
pressing and holding the recall switch (1, 2 or 3) with KL 15
“ON” or tapping the recall button (1, 2 or 3) with:
• The driver’s door open and KL 15 “OFF”.
• KL R ON and KL 15 “OFF”.
The recall movement can be interrupted at any time by touching any of the adjusting
switches.
E38/E39
E53
615200133.tiff

Mirror
Principle of Operation
The output stages and memory storage of mirror positions is handled by the respective
door modules. The positioning of the mirrors is signaled from the driver’s door switch
block/module. The signal passes over the P-Bus to the passenger’s door module.
The memory/recall for the driver’s mirror comes directly into the door module from the
memory switch. The operation for the passenger’s side mirror is carried out over the P-Bus
from the driver’s door module to the passenger’s door module.
The memory positions are stored in each respective module. The memory position is rec-
ognized by the feedback potentiometers located on each mirror motor.
The reverse gear tilt feature for the passenger’s mirror is signaled from the GM, over the P-
bus, when reverse is selected and the mirror switch is set for the driver’s side.
Mirror heating is controlled by each respective door module. The GM receives the outside
temperature from the IKE and passes it to the door modules. The “ON” time for mirror heat-
ing is adjusted based on the outside temperature.
A pulsed heating cycle is used for the mirrors based on the outside temperature.
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Central Body Electronics ZKE III
Temperature<-10OC -10 to 0OC 0 to 15OC 15 to 25OC >25OC
ON - duration 100% 75% 50% 25% 5%
E39 Shown

Driver’s Seat (E38/E39)
Principle of Operation
Each motor for seat adjustment contains a micro-processor (called a Ripple Counter) that
receives a digital signal from the seat control module for motor activation. The motors are
connected to KL 30 and KL 31 and respond to the signals generated by the seat module
when seat movement is requested. The seat adjustment switch provides ground input sig-
nals to the module when seat movement is desired. The module processes these input sig-
nals and sends output signals to the seat motor processors. The seat motor processors
activate the motors and the seat moves to the desired point.
The circuitry of the Ripple Counter detects the motor activation current. As the armature
segments of the motor rotate passed the brushes, the current flow rises and falls produc-
ing a ripple effect. The peaks of these ripples are counted and stored in the Ripple Counter
module. The memory function of the seat module uses this ripple count instead of feed-
back potentiometers to memorize and recall seat positions.
Ripple Count Recognition:
When the seat is installed and the
battery is connected, the ripple
counter uses the initial position of
the motors as the “Zero Position”.
Any movement from this point is
counted as “+” or “-” pulses as
the motors move in either direc-
tion.
The pulse position of the motors is stored in the seat module, in an EEPROM (of the PM-
SM), before the ZKE goes into its “Sleep Mode”.
This prevents the position recognition from being lost. If the battery is disconnected before
the 16 minute sleep mode activation, the memory positions of the seat will be lost and
reprogramming will be required.
Diagnosis: The PM-SM communicates with the DISplus or MoDiC. The PM-SM monitors
the seat motors and circuits as well as it's internal operation. Any detected faults are stored
in the PM-SM fault memory and are called up when diagnosing the system with the Fault
Symptom diagnostic plan. The PM-SM also provides status display to the DISplus of the
input and output control signals as well as component activation.
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Central Body Electronics ZKE III
615200137.eps

Passenger’s Seat (without memory)
Principle of Operation
The passenger seat control switch is purely a mechanical switching module that activates
the passenger seat motors without position monitoring capabilities. Due to the limited op-
eration requirements, the passenger seat control switch is not equipped with on board
diagnostics.
The Passenger Seat control switch is equipped with an overload protection function. If
excessive amperage is drawn due to a defective motor or a switch is stuck driving a motor
to the end limit, the function activates opening the motor control circuit.
Passenger Seat Motors: Each motor is individually controlled by the Seat Control Switch.
Each position motor is connected to the seat position switch by a two wire circuit provid-
ing motor activation in both directions (no position recognition).
Passenger Seat Adjustment: Operation of the passenger seat is always possible regard-
less of the ignition key position. Moving a position switch operates a the motor control con-
tacts directly, the switch applies voltage and ground path directly to operate the motor.
Reversing the switch simply changes the motor polarity. More than one passenger seat
motor can be run simultaneously.
Optional Seat Back Lumbar Support
The optional air bladder lumbar support system is similar in all
vehicles (if equipped). Each seat contains the following com-
ponents:
• Four position circular rocker switch in the seat base trim in
the area of the seat switches.
• Electrically controlled air compressor with over pressure cut
out under each seat.
• Two solenoid activated air controlling valve blocks (one per
air bladder). Each valve block includes an inlet and an outlet
valve. When energized they direct air into the bladder(s) to
inflate or relieve trapped air to deflate the bladders.
• Connecting hoses and air bladders in lower seat back.
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Central Body Electronics ZKE III

Principle of Operation
The lumbar support system can be operated at any time regardless of key position. The
four position circular rocker switch provides power switching to operate the system as fol-
lows:
• Position 1: The internal switch contacts provide a power and ground path for both valve
block inlet valves and the air compressor. Both bladders inflate until the switch is
released. If the switch is held continuously, an overpressure bypass valve opens on the
compressor preventing damage to the bladders.
• Position 2: Compressor activated, upper bladder inflates, lower bladder deflates.
• Position 3: Compressor activated, lower bladder inflates, upper bladder deflates.
• Position 4: Compressor is not activated. Upper and Lower bladders both deflate.
This function is not stored in memory for recall.
Diagnosis
The seat lumbar support system is purely electro-pneumatic control system. No electron-
ic diagnostic communication is possible.
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Central Body Electronics ZKE III

Principle of Operation
To activate this feature, the ignition must be in
the KL R or KL 15 and press the switch located
in the Center Console Switch Center (driver and/
or passenger front seat).
The switch provides a ground to the control
module and an LED in the switch will illuminate.
If there is a fault in the system the LED will not
illuminate.
The control module, fluid bladders (2 and 3) and
pump (1) is contained in each seat. The pump
contains a Hall sensor to monitor the number
motor revolutions and two pressure sensors to
monitor each bladder for vacuum (indicating
empty).
The fluid bladders (2 per seat) contain water-
glysantin mixture and are connected to the fluid
pump. The fluid bladders are equal in volume at
rest (15 mm. high) and will raise from 0 up 30
mm. when filled alternately from left to right.
Note: The pump unit and fluid bladders are replaced as a unit.
The control modules (one per seat) are connected to the P-Bus. The driver’s side control
module contains an acceleration sensor that monitors transverse acceleration of the vehi-
cle. Active Seat operation is temporarily interrupted during high acceleration.
Rear Power Seat (E38 750iL)
The rear seats in the 750iL provide electric adjustments for:
1. Backrest Angle - Control switch powers the motor.
2. Headrest Height - Control module behind each upper seat.
3. Lumbar Support
The headrest automatically extends when a passenger fastens
the safety belt and will automatically retract when the safety
belt is released. The power rear seat is a purely electric control
system. No electronic diagnostic communication is possible.
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Central Body Electronics ZKE III

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Central Body Electronics ZKE III
Seat Heating Operation (from 99 MY)
Principle of Operation
The front seat heaters are adjustable through three ranges of
heating output temperature.
Pressing the respective seat heater button once provides
stage 1:
• All three LEDs illuminate and the heating elements are provided regulated output current
producing a seat temperature of 111
OF.
Pressing the button a second time provides stage 2:
• The top LED switches off and the heating elements are regulated to an output tempera-
ture of 102
OF.
Pressing the button a third time provides stage 3.
• The top and middle LEDs are off and the heating elements are regulated to an output tem-
perature of 95
OF.
The SZM monitors the seat heating element temperature via an NTC feedback signal to
regulate the output current which maintains the seat temperature.
Seat heating is switched off by pressing the button a fourth time,
pressing and holding the
button for more than 1 second or when the ignition is switched off.
System Components
Carbon Fiber Heating Pads:In each seat is a two
section heating pad wired in parallel. The heating pads
are resistors which when powered produce radiant
heat.
The seat base heating element also contains a temper-
ature sensor for feedback to provide the temperature
regulation output control.
KL31
KL15
TEMPERATURE
SENSOR
615200139.eps

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Central Body Electronics ZKE III
Center Console Switch Center (SZM): From 1999 MY E38, E39 and E53 vehicles are
equipped with a SZM to control the front seat heating and provide a diagnostic interface
with the DISplus/MoDiC via the K BUS.
The SZM directly controls:
• Front Seat Heating
• Rear Window Roller Blind
SZM also provides a unitized switching center
for:
• Park Distance Control (PDC)
• Dynamic Stability Control (DSC III)
• Electronic Damper Control (EDC).
The switch signal output for these systems is a direct output signal. All diagnosis functions
are carried out through their respective control systems.
SZM Monitoring of Seat Heating
Battery Voltage:The SZM switches current supply to the heating elements off when bat-
tery voltage drops below 11.4 volts. However, the heating stage LEDs remain on.
Regulated output current resumes when battery voltage raises above 12.2 volts for more
than 5 seconds.
SZM Internal Temperature: The power output stages for the seat heating elements gen-
erate a considerable amount of heat when in stage 1 operation. The SZM monitors it’s own
internal temperatures and reduces the heating output when internal temperatures rise to a
temperature of 185
OF or switches it off completely above 203OF. As with battery voltage
monitoring, the heating stage LEDs remain on when these temperatures are exceeded.
Fault Monitoring:The SZM monitors the temperature sensors and heating mats for faults.
Detected faults are stored in the SZM. Fault Symptom Troubleshooting in conjunction with
stored faults will initiate the diagnostic paths using the DISplus/MoDiC. The following faults
can be recognized:
• Shorts or opens in the wiring circuits.
• Shorts or opens in the temperature sensors.
• Open in heating element.
If a short is detected in the temperature sensor, the seat heating is switched off to prevent
overheating. The Stage LEDs are also switched off with this fault present.