Sunroof / Moonroof: Description and Operation
Roof Opening Panel
COMPONENT LOCATION
OVERVIEW
The roof opening panel is electrically operated by a three-way switch located on the forward interior light assembly. The roof opening panel drive unit moves the roof opening panel to the tilt open or closed positions. The unit is actuated by the integrated roof opening panel control electronics.
The roof opening panel frame is bolted to mounting points on the roof panel. The frame, constructed from pressed steel, supports all the roof opening panel components.
A rubber gaiter is fitted between the sides of the glass panel and drive assembly. The gaiter reduces wind noise with the roof opening panel in the tilt position and conceals the drive linkage.
The roof opening panel drive unit is accessible by removing the motor access panel (integral with the forward interior light assembly). The drive unit is mounted ahead of the roof segment between the roof liner and lower frame section of the roof opening panel. It comprises a motor with add-on reduction gear (worm drive), two Hall-effect integral position sensors and integrated control circuit.
The worm drive drives a gear in a cast housing attached to the end of the motor. The gear has a small pinion gear attached to the outer part of its spindle. The pinion engages with the spiral cables to form a rack and pinion drive. Rotation of the motor turns the pinion which in turn drives the cables in the required direction.
Two cables are attached to either side of the pinion. One end of each cable is attached to the guide. The opposite end is clamped in its position on the pinion by a riveted bracket. The cables run in metal tubes to the guides. As the roof opening panel is closed, the cables are pulled through the metal tubes. The displaced cable is guided into plastic tubes which protect the cable and prevent it snagging. The cables are made from rigid spring steel and therefore can push as well as pull the roof opening panel along the guides.
A sunshade is also located in the guides. When the roof opening panel is opened or tilted, the sunshade moves rearward. When the roof opening panel is opened, two brackets on the sunshade engage with the panel as it is retracted. The sunshade is then pulled back by the retracting panel. When the panel is closed, the sunshade remains retracted until pulled manually to its closed position.
Drain hoses are connected to the front and rear corners of the frame. The drain hoses are located inside the 'A' and 'D' pillars to allow water which has collected in the frame to escape. A one-way valve is fitted to the end of each drain hose to prevent the ingress of dirt and moisture.
CONTROL MODULE
The roof opening panel control module is integral with the drive motor, and is mounted behind the headlining at the front of the vehicle. The control module connects to the vehicle wiring via a 13 pin electrical connector. The software contained within the control module is configured to meet individual national regulations.
The control module communicates to the GEM (generic electronic module) and both front door modules via the P bus.
CONTROL DIAGRAM
NOTE: A = Hardwired; M = P bus
PRINCIPLES OF OPERATION
Anti-Trap
The anti-trap feature is configured to meet the specific requirements of individual national regulations. The system operates by monitoring the torque output of the sliding/tilting roof opening panel drive. It operates when the roof opening panel is closing and the opening is greater than 4 mm. To ensure that the roof opening panel fully closes it is disabled for the last 4 mm of travel.
If activated, the anti-trap feature returns to roof opening panel to the point at which the close selection was initially made.
The control module disables the anti-trap feature when emergency closing (panic mode) is selected.
Sleep Modes
To reduce the current consumption of the vehicle, the roof opening panel control module switches to an electricity-saving mode after receiving the message "Go to Sleep" from the GEM (generic electronic module) via the P bus. In this condition manual operation of the roof opening panel will result in the loss of its absolute position. If this occurs, the roof opening panel will require re-initializing.
The electricity-saving mode is exited on receipt of a message from the GEM (generic electronic module) via the P bus.
Shutdown
During the engine cranking process (ignition position III), the GEM (generic electronic module) requests the roof opening panel control module to inhibit roof opening panel operation via the P bus. Any requested movement is halted until the ignition switch is returned to position II.
If the voltage supplied to the roof opening panel control module drops below 9.5 V, any one-touch operation currently in progress will be terminated and no new roof opening panel movement will be initiated.
Initialization
Initializing the roof opening panel allows the control module to learn the end positions of the motor's travel. Hall sensors in the motor provide pulses for motor spindle rotation. The control module counts the pulses and determines where the panel is by memorizing the stored pulses.
If the system is not initialized, the roof opening panel will only operate in the tilt up and slide close positions. To initialize the roof opening panel:
^ Using the switch, move the roof opening panel to the full tilt position and hold for 20 seconds.
^ Release the switch.
^ Using the switch, close the roof opening panel.
^ Using the switch, slide the roof opening panel fully open, then fully closed.
Diagnostics
The roof opening panel control module has a built in test function to allow self-checking and self-diagnosis.
Exchange of data with the Land Rover approved diagnostic system takes place via the GEM (generic electronic module) and the P bus. It can be used to identify 3 possible faults.
^ Mechanical stiffness (fault in the roof opening panel unit)
^ Implausible input signals (control fault)
^ Electronic fault.