1997 BMW 740IL battery

oil viscosity transmission oil warning light deactivate airbag snow chains brake light

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BMW 740IL 1997 E38 Central Body Electronics ZKE Manual • Signal "NG"; switched ground output signal provided to the GM. The signal is used for
two purposes,
1. As a momentary acknowledgment that the tilt sensor received STDWA and is cur-
re

• Signal "NG"; switched ground output signal provided to the GM. The signal is used for
two purposes,
1. As a momentary acknowledgment that the tilt sensor received STDWA and is cur-
rently monitoring the vehicle angle.
2. If the tilt sensor detects a change in the vehicle's angle when DWA is armed, signal
NG is switched to inform the GM to activate the siren.
When the tilt sensor receives the STDWA signal from the GM it memorizes the vehicle's
parked angle. The angle of the vehicle is monitored by the solid state electronics. Once
armed, if the angle changes, the tilt sensor provides a switched ground signal to the GM
to activate DWA.
As with the interior sensor, the tilt sensor is also switched OFF when the vehicle is locked
two times within ten seconds. The LED will flash one time for confirmation. This allows the
sensor to be switched OFF for transportation purposes.
Glass Breakage Sensors (Early E38 - before FIS Sensor): The door windows (includ-
ing the rear quarter glass wire loop) are monitored by inductive sensors mounted on the
inside of the door behind the trim panel. A closed window is recognized by a magnetic plate
on the glass lining up with the sensor.
If the glass is broken, the plate falls away and the signal from the sensor changes and the
GM will activate the alarm.
Alarm Siren: The alarm siren is mounted in the rear wheel well, behind the inner wheel
housing cover (early E38 used an alarm horn). The E53 alarm siren is located in the left side
of the engine compartment.
The siren contains electronic circuitry for producing the warn-
ing tone when the alarm is triggered. The siren also contains a
rechargeable battery that is used to power the siren when the
alarm is triggered.
The rechargeable battery will allow the siren to sound if it or the
vehicle’s battery is disconnected. The siren battery is
recharged, from the vehicle’s battery, when the alarm is not in
the armed state.
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Central Body Electronics ZKE III
625200108.eps

Page 38 of 80

BMW 740IL 1997 E38 Central Body Electronics ZKE Manual The siren has four wires connecting it to the system; KL 30, KL 31, activate siren signal
(SIRENE) and the arm/disarm signal (STDWA).
The arm/disarm output signal from the GM is

Page 62 of 80

BMW 740IL 1997 E38 Central Body Electronics ZKE Manual 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 mot

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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BMW 740IL 1997 E38 Central Body Electronics ZKE Manual 68
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 prov

68
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.

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BMW 740IL 1997 E38 Central Body Electronics ZKE Manual Rear Window Roller Sunblind Operation
The roller sunblind is activated by momentarily pressing and releasing (one touch) the sun-
blind rocker switch in the SZM. The SZM activates the motor in the app

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BMW 740IL 1997 E38 Central Body Electronics ZKE Manual General Functions of ZKE III
Consumer Cut Off
The Consumer Cut Off function interrupts battery voltage to circuits preventing inadvertent
battery drain if one of these consumers were to remai

Page 76 of 80

BMW 740IL 1997 E38 Central Body Electronics ZKE Manual Sleep Mode
To lower the constant battery draw when the vehicle is parked, the complete ZKE system
will go into the “Sleep Mode” 16 minutes after the ignition has been switched off a

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BMW 740IL 1997 E38 Central Body Electronics ZKE Manual Battery Status
The GM monitors KL R on a dedicated circuit. If the ignition is switched on and detected
via the KL R circuit but the GM does not receive KL R status via the K Bus, the

Battery Status
The GM monitors KL R on a dedicated circuit. If the ignition is switched on and detected
via the KL R circuit but the GM does not receive KL R status via the K Bus, the GM mon-
itors the KL R voltage level. If after an additional 0.3 seconds there is no K Bus activity, the
GM initiates an emergency running program.
A substitute value for vehicle speed is used to allow the GM to operate certain functions.
The emergency running program will terminate if the GM detects a vehicle speed or KL R
status via the K bus.
Diagnosis/Troubleshooting
The GM contains an EEPROM fault memory. Diagnosis and troubleshooting is carried out
with the DISplus or MoDiC. The diagnostic link is through the Instrument cluster over the K
bus to the GM.
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Central Body Electronics ZKE III

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