sunroof BMW 750IL 1996 E38 Central Body Electronics ZKE Manual

Sunroof Motor/Module (SHD): The motor is powered to open, close and lift the sunroof
panel. The motor contains two hall effect sensors that monitor the motor shaft rotation pro-
viding sunroof panel position.
The hall sensors also provide the end limit cut
out function for the SHD once the system is ini-
tialized. The SHD counts the pulses and cuts
the motor out prior to the detected end run of
the sunroof panel.
The combined motor module has a pin con-
nector for interfacing the switch, and vehicle
harness (power, ground and Bus.)
The electronic controls and relays are contained in the sunroof module (PM-SHD). The
module is connected to the P-Bus (E38 >99 MY on the K-Bus) for comfort closing/open-
ing and diagnosis/fault memory purposes.
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Central Body Electronics ZKE III
System Components: Inputs - Processing - Outputs
/K-BUS

Principle of Operation
Initialization: Initialization is required for the SHD to learn the end positions of the motor's
travel. The hall sensors provide pulses for motor rotation, the SHD counts the pulses and
determines where the panel is by memorizing the stored pulses.
If the system is not initialized, the sunroof will only operate in the tilt up and slide close posi-
tions. Initialize as follows:
• Press and hold the sunroof switch in either the tilt up or slide close positions for 15 sec-
onds.
• The sunroof motor operates momentarily signifying initialization acceptance.
The SHD memorizes the pulses from the hall sensors on the next activation of the motor
by driving the panel to its end run positions. The SHD senses an amperage increase and
determines the end run position. The counted number of pulses is then used as the basis
for calculating the panel position.
Anti-Trap Feature: The anti-trap feature of the sunroof uses a hall sensor to detect
obstructions while the sunroof is closing (pulse frequency slowed down) in the automatic
close function. The anti-trap feature is shut down prior to full closing (4mm from full closed)
to allow the sunroof to seat into the seal.
Note: The anti-trap feature is not functional when the switch is held in the manual close
position.
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Central Body Electronics ZKE III

Workshop Hints
SHD Self Diagnosis
The SHD monitors operation and stores fault codes if a defect is determined. The SHD
monitors the following conditions:
• SHD motor relays:The relays are checked for sticking contacts (plausibility) and non
functional contacts.
• Hall effect position sensors:The SHD must detect a pulse frequency from the hall
effect sensor(s) during operation.
• Sunroof Switch: The SHD monitors the signal plausibility of the coded signaling from
the sunroof switch.
Sunroof Fault Response Characteristics
If a fault occurs with any of these functions, the SHD responds as follows:
• Overrides the end run detection.
• Switches the motor off if the relay contacts stick for more than 500 ms.
• Switches the motor off if pulses are not received.
Emergency Operation of the Sunroof
If the sunroof motor does not respond to the switch signals, the hex key in the trunk lid tool
kit is used to manually turn the motor shaft drive.
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Central Body Electronics ZKE III

Review Questions
1. List the functions directly controlled by the GM III._______________________________
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2. How does the GM III communicate with other control modules?__________________
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3. What effect does road speed have on the wiper system? What effect does it have on
an AIC equipped vehicle? Where does the road speed come from?_______________
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4. How does the GM III recognize the key position from the drivers door?____________
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5. Describe the procedure used by the GM III to recognize an FZV key. Can the GM
differentiate between different keys? How many can it recognize?________________
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6. What “convenience” features are available from the FZV key?____________________
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7. Describe what happens when the GM receives the crash signal from the MRS.
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8. Why does the SHD (sunroof) module require initialization but the windows do not?
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Central Body Electronics ZKE III