1999 BMW X5 seat

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DRIVER’S SEAT MEMORY (CAR Memory Influence)
The PM-SM can be encoded to recall a specific seat position for a vehicle user when the
GM signals the SM to automatically recall stored positions separate of the 1-2-3 button
selections.
This feature is encoded through the car memory function and activated by the key memo-
ry function. The PM-SM will monitor the seat position and store it in another area of it's
memory when the vehicle is locked with the remote keyless entry system. The GM sends
a request to memorize the seat position and store it for FZV key user 1,2,3 or 4.
If another user of the vehicle changes the seat position the PM-SM restores the memory
position the next time the specific key is used to unlock the vehicle.
This feature can be further modified to activate the position recall based on the owner's
selected activation scenario, for example: The owner can choose to :
• Disable this feature,
• Initiate memory recall when the unlock signal is initially sent before a door is opened.
• Initiate memory recall when the unlock signal is sent but only when the driver's door is
opened.
See Car Memory Key Memory for additional information.
POWER SEAT DIAGNOSIS
The PM-SM communicates with the DIS or MoDiC via the K bus - instrument cluster gate-
way - to the P-bus. The PM-SM monitors the seat motors and circuits as well as it's inter-
nal 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 DIS of its input and output control signals
as well as component activation.

SEAT 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 direction. The pulse position of the motors
is stored in the seat module, in an EEPROM, 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.
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STEERING COLUMN OPERATION
The adjustable steering column is similar to the E38 in components, mechan-
ical linkages and electrical operation. The steering column adjusting switch is
mounted on the left side of the steering column and provides for four directions
of column movement.
The motors for tilt and length also employ ripple counter modules for motor control and
memory recall. The control electronics for the steering column are integrated into the seat
module. The steering column switch inputs are processed by the seat module and the out-
put signals are sent to the steering column ripple counter modules for motor activation.
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RIPPLE
COUNTER

GENERAL FUNCTIONS OF ZKE III
CONSUMER CUT OFF
The interior lights are connected to the consumer cut out circuit. These consumers are con-
nected to KL 30 and can remain on if one of the control switches are left on. This would
prevent the ZKE from going into the sleep mode. However, the consumer cut off will switch
Kl 30, to the interior lighting, off after 16 minutes.
OVERLOAD PROTECTION
The seat and steering column motors are provided operating power through the consumer
cutoff / overload protection relay module as on the E38. The consumer cutoff signal from
the GM signals the relay to maintain operating power to the consumers.
If an overload condition exists, the relay module detects the increase in amperage and
opens the relay. The relay module is located in the electrical carrier forward of the glove
box.
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