DESCRIPTION AND OPERATION
4.18 RANGE ROVER
Sunroof ECU
The sunroof ECU (C0784) provides a feed to the sunroof switch (C0363) on a YS wire. If the
switch is moved to the 'Open' position, a feed is returned to the ECU (C0784) on a YG wire.
The ECU will now power the sunroof motor to open the sunroof. By measuring the voltage
pulses returned from two Hall effect sensors located within the sunroof mechanism, the ECU
can determine when the sunroof has reached the end of its travel and cut the voltage supply
to the motor.
If the switch is moved to the 'Close' position, a feed is returned to the sunroof ECU (C0784)
on an SB wire. The ECU will now power the sunroof motor to close the sunroof. By
measuring the voltage pulses returned from the two Hall effect sensors, the ECU determines
when the sunroof has reached the end of its travel and cuts the voltage supply to the motor.
If the centre of the switch is pressed, a feed is returned to the sunroof ECU (C0784) on a
YW wire. The ECU will now power the sunroof motor in the 'Close' direction to raise the rear
of the sunroof. By measuring the voltage pulses returned from the two Hall effect sensors,
the ECU determines when the sunroof has reached the end of its travel and cuts the voltage
supply to the motor.
If the centre of the switch is pressed a second time, a feed is returned to the sunroof ECU
(C0784) on a YW wire. The ECU will now power the sunroof motor in the 'Open' direction to
lower the sunroof. By measuring the voltage pulses returned from the two Hall effect
sensors, the ECU determines when the sunroof has reached the end of its travel and cuts
the voltage supply to the motor.
The sunroof ECU (C0784) is earthed on an N wire.
Body Control Unit (BCU)
The Body Control Unit (BCU) (C0660) communicates with the sunroof ECU (C0784) via the
P-Bus. In addition to enabling automatic opening and closing to be carried out, the BCU also
triggers the sunroof ECU into an energy saving 'sleep' mode.
For a detailed description of P-Bus operation and messages, refer to the Communication
Databuses section of the System Description Operation Workshop Manual.
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