Sunroof Land Rover Discovery L318

Scheme 1

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General

The sunroof system consists of a front and a rear sunroof assembly. Both sunroof assemblies slide and tilt to open. The sunroof system consists of the following components

1. Sunroof ECU.
2. BCU.
3. Front sunroof switch.
4. Front sunroof motor and microswitch.
5. Rear sunroof - front switch.
6. Rear sunroof - rear switch.
7. Rear sunroof isolation switch.
8. Rear sunroof motor and microswitch.

The BCU enables operation of the sunroof ECU. If the sunroof ECU does not receive an enable signal from the BCU, neither sunroof assembly operates. The BCU is located behind the glovebox. The sunroof ECU is located above the headlining next to the front sunroof assembly.

TestBook diagnoses the sunroof ECU.

Scheme 4

The front sunroof switch is located in the roof console above the windscreen in front of the front sunroof. It controls the front sunroof motor via the sunroof ECU.

The front sunroof switch supplies an earth signal to the sunroof ECU. The pin at the ECU that receives the earth signal determines whether ECU causes the sunroof to open or close.

TestBook cannot monitor the state of the front sunroof switch.

The following table lists the values which can be measured at the listed ECU pins when the conditions outlined are met

SIGNAL VALUES (CONNECTOR CONNECTED)

SIGNAL VALUES (CONNECTOR CONNECTED)

Scheme 5

The front sunroof motor is located within the front sunroof assembly. The sunroof ECU controls the front sunroof motor.

The sunroof ECU determines the direction the sunroof motor runs. A battery signal to one side of the motor and an earth to the other side of the motor causes the motor to turn in one direction, reversing the polarity through the same pins causes the motor to turn in the opposite direction.

The following table lists the values which can be measured at the listed ECU pins when the conditions outlined are met

SIGNAL VALUES (CONNECTOR CONNECTED)

Scheme 6

The rear sunroof front switch is located in the roof console above the windscreen in front of the front sunroof. It controls the rear sunroof motor via the sunroof ECU.

The rear sunroof front switch supplies an earth signal to the sunroof ECU. The pin at the ECU that receives the earth signal determines whether ECU causes the sunroof to open or close.

TestBook cannot monitor the state of the rear sunroof front switch.

The following table lists the values which can be measured at the listed ECU pins when the conditions outlined are met

SIGNAL VALUES (CONNECTOR CONNECTED)

Scheme 7

The rear sunroof isolation switch is located in the roof console above the windscreen in front of the front sunroof. It prevents the rear sunroof rear switch from operating the rear sunroof.

The rear sunroof isolation switch is in the earth path between the rear sunroof rear switch and the sunroof ECU. Operating the rear sunroof isolation switch opens the circuit and prevents the rear sunroof rear switch from operating the rear sunroof.

TestBook cannot monitor the state of the rear sunroof isolation switch.

The following table lists the values which can be measured at the listed ECU pins when the conditions outlined are met

SIGNAL VALUES (CONNECTOR CONNECTED)

Scheme 8

The rear sunroof rear switch is located in the roof console in front of the rear sunroof. It controls the rear sunroof motor via the sunroof ECU.

The rear sunroof front switch supplies an earth signal through the rear sunroof isolation switch to the sunroof ECU. The pin at the ECU that receives the earth signal determines whether ECU causes the sunroof to open or close.

TestBook cannot monitor the state of the rear sunroof rear switch.

The following table lists the values which can be measured at the listed ECU pins when the conditions outlined are met

OPERATING PARAMETERS (CONNECTOR CONNECTED)

Scheme 9

The rear sunroof motor and microswitch are located within the rear sunroof assembly. The sunroof ECU controls the rear sunroof motor.

The sunroof ECU determines the direction the sunroof motor runs. A battery signal to one side of the motor and an earth to the other side of the motor causes the motor to turn in one direction, reversing the polarity through the same pins causes the motor to turn in the opposite direction.

SUNROOF ECU CONNECTOR PIN DETAILS - C0784

Scheme 10

The sunroof ECU is located behind the head lining above the rear view mirror. Most functions of the sunroof ECU are covered under other components.

SUNROOF ECU CONNECTOR PIN DETAILS - C0785

Sunroof ECU connector pin details - C0785

Ignition switched-off timeout

There are three timeout modes for operating the sunroof assemblies after the ignition is switched off. The BCU determines the vehicle's timeout mode. The three modes are

1. When the ignition is switched off, no sunroof operation is permitted.
2. When the ignition is switched off, sunroof remains functional for 45 seconds or until the driver door is opened.
3. When the ignition is switched off, sunroof remains functional for 45 seconds or until any door is opened.

Both sunroof assemblies operate in the same manner. The front sunroof assembly has one switch while there are two switches to control rear sunroof assembly, a rear sunroof front switch and a rear sunroof rear switch.

The sunroof ECU monitors the position of the sunroof microswitch to determine if the sunroof is to be tilted or opened.

In order for the sunroof to operate, either of the following conditions must exist

1. Ignition switch in position II.
2. Ignition switched from on to off, doors closed (this may enable the system to operate for 45 seconds after the ignition is switched off, or until a door is opened).

When the sunroof is closed, pressing the rear of the sunroof switch causes the sunroof ECU to operate the sunroof motor and open the sunroof. When the sunroof opens, the sunroof microswitch opens. The sunroof continues to open until the switch is released or the sunroof reaches the fully open position.

When the sunroof is open, pressing the front of the sunroof switch causes the sunroof ECU to operate the sunroof motor and close the sunroof. The sunroof ECU continues to operate the motor until the sunroof microswitch closes. This indicates to the sunroof ECU that the sunroof is fully closed.

Both sunroof assemblies operate in the same manner. The front sunroof assembly has one switch while there are two switches to control rear sunroof assembly, a rear sunroof front switch and a rear sunroof rear switch.

The sunroof ECU monitors the position of the sunroof microswitch to determine if the sunroof is to be tilted or opened.

In order for the sunroof to operate, either of the following conditions must exist.

1. Ignition in position II.
2. Ignition switched from on to off, doors closed (this may enable the system to operate for 45 seconds after the ignition is switched off, or until a door is opened).

When the sunroof is closed and the front of the sunroof switch is pressed, the sunroof ECU detects the combination of closed microswitch and front of sunroof switch being pressed and tilts the rear of the sunroof. This causes the microswitch to open. The sunroof continues to open until the switch is released or the sunroof reaches the fully open position.

When the sunroof is tilted and the rear of the sunroof switch is pressed, the sunroof ECU detects the combination of open microswitch and rear of sunroof switch and closes the sunroof until the microswitch closes. This indicates to the sunroof ECU that the sunroof is fully closed.

The rear sunroof isolation switch prevents the rear sunroof rear switch from operating the rear sunroof. This can be used to prevent small children sitting in the rear seat from playing with the rear sunroof.

Pressing the rear sunroof isolation switch opens the circuit between the rear sunroof rear switch and the sunroof ECU. The sunroof ECU ignores the rear sunroof switch until the rear sunroof isolation switch is pressed and the circuit closes.

A feed from the battery positive terminal is connected on an R wire to the engine compartment fusebox where it passes through fusible links 1, 6 and 8. Fusible links 1 and 6 are connected in series.

The feed from fusible links 1 and 6 is connected on an NU wire to the passenger compartment fusebox where it passes through fuse 12. The feed is connected from fuse 12 to supply a continuous battery feed on an NR wire to the sunroof ECU pin C0785-3.

The feed from fusible link 8 is connected on an NW wire to the passenger compartment fusebox and from the fusebox to the ignition switch on an N wire.

Ignition Switch Circuit Supply

With the ignition switch in position II, the feed from fusible link 8 passes through the ignition switch to the passenger compartment fusebox on a Y wire, where it passes through fuse 29. The feed is connected from fuse 29 to the Body Control Unit (BCU) pin C0660-1 on a GU wire.

Scheme 11

1. Remove headlining. Refer to «REMOVE»(/land-rover/discovery/l318-2002-2004/remont/exteriorinterior-trim/#interior-trim-components) .
2. Remove front sunroof motor. Refer to «MOTOR - SUNROOF»(/land-rover/discovery/l318-2002-2004/remont/sun-rooft-topconvertible-top/#sunroof) .
3. Disconnect drain tubes from sunroof tray.
4. Remove 14 screws securing sunroof tray to sunroof frame.
5. Carefully remove sunroof tray.
6. With assistance, remove sunroof frame and glass assembly.

Scheme 12

1. With assistance, fit sunroof frame and glass assembly.
2. Position sunroof tray to roof and locate on front edge and on rear location pin, arrowed in illustration.
3. Fit Torx screws securing sunroof tray to frame and tighten to 2 Nm (1.5 lbf.ft) in the order shown.
4. Connect drain tubes to sunroof.
5. Fit sunroof motor. Do not fit headlining at this stage. Refer to «MOTOR - SUNROOF»(/land-rover/discovery/l318-2002-2004/remont/sun-rooft-topconvertible-top/#sunroof) .
6. Check operation of sunroof.
7. Pour water over sunroof and check for water leaks.
8. Fit headlining. Refer to «REFIT»(/land-rover/discovery/l318-2002-2004/remont/exteriorinterior-trim/#interior-trim-components) .

Scheme 13

Scheme 14

1. Remove sunroof motor. Refer to «MOTOR - SUNROOF»(/land-rover/discovery/l318-2002-2004/remont/sun-rooft-topconvertible-top/#sunroof) .
2. Models with rear A/C: Drill out 4 rivets securing rear center duct to roof. Release and remove rear center duct. Drill out 2 rivets securing each upper side duct to roof. Remove upper side ducts.
3. Disconnect drain tubes from sunroof tray.
4. Remove 14 screws securing sunroof tray to sunroof frame.
5. Carefully remove sunroof tray.
6. With assistance, remove sunroof frame and glass assembly.

Scheme 15

1. With assistance, fit sunroof frame and glass assembly.
2. Position sunroof tray to roof and locate on front edge and on rear location pin, arrowed in illustration.
3. Fit Torx screws securing sunroof tray to frame and tighten to 2 Nm (1.5 lbf.ft) in the order shown.
4. Fit sunroof motor. Do not fit headlining at this stage. Refer to «MOTOR - SUNROOF»(/land-rover/discovery/l318-2002-2004/remont/sun-rooft-topconvertible-top/#sunroof) .
5. Models with rear A/C: Fit upper side ducts and secure with rivets. Fit rear center duct and secure with rivets.
6. Connect drain tubes to sunroof.
7. Check operation of sunroof.
8. Pour water over sunroof and check for water leaks.
9. Fit headlining. Refer to «REFIT»(/land-rover/discovery/l318-2002-2004/remont/exteriorinterior-trim/#interior-trim-components) .

The procedure for replacing the rear sunroof glass panel is exactly the same as for the front

Scheme 16

1. Partially open sunroof.
2. Remove 4 Torx screws securing glass to sunroof frame.
3. Remove sunroof glass.

Refit

1. Position glass to frame.
2. Fit Torx screws securing glass to sunroof frame. Do not fully tighten screws at this stage.
3. Adjust position of sunroof glass in relation to roof panel until a 6.5 mm (0.25 in) gap is produced between the front edge of the glass and the sunroof frame.
4. Tighten sunroof glass retaining screws to 3 Nm (2.2 lbf.ft).

This procedure is applicable to the motor of both sunroofs.

Scheme 17

1. Gain access to the sunroof motor: For front sunroof motor, remove front stowage pocket. Refer to «REMOVE»(/land-rover/discovery/l318-2002-2004/remont/exteriorinterior-trim/#interior-trim-components) . For rear sunroof motor, remove headlining. Refer to «REMOVE»(/land-rover/discovery/l318-2002-2004/remont/exteriorinterior-trim/#interior-trim-components) . CAUTION: The sunroof must be fully closed before removing the sunroof motor.
2. Disconnect sunroof motor multiplug.
3. Remove 3 Torx screws securing motor to sunroof tray.
4. Remove sunroof motor.

Scheme 18

1. Check sunroof motor timing notch (A) aligns with edge of microswitch (B). If motor is out of alignment, rotate counting wheel (C) to correct position using an Allen key.
2. Ensure sunroof drive cables are in fully closed position.
3. Fit motor to sunroof frame.
4. Fit Torx screws securing motor to sunroof tray and tighten to 2 Nm (1.5 lbf.ft).
5. Connect sunroof motor multiplug.
6. Fit interior trim: For front sunroof motor, fit front stowage pocket. Refer to «REFIT»(/land-rover/discovery/l318-2002-2004/remont/exteriorinterior-trim/#interior-trim-components) . For rear sunroof motor, fit headlining. Refer to «REFIT»(/land-rover/discovery/l318-2002-2004/remont/exteriorinterior-trim/#interior-trim-components) .

76.84.09 Drive cable assembly

This procedure is applicable to the drive cable assembly of both sunroofs.

Scheme 19

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Scheme 21

1. Remove sunroof: For front drive cable assembly: Refer to «SUNROOF - FRONT»(/land-rover/discovery/l318-2002-2004/remont/sun-rooft-topconvertible-top/#sunroof) . For rear drive cable assembly: Refer to «SUNROOF - REAR»(/land-rover/discovery/l318-2002-2004/remont/sun-rooft-topconvertible-top/#sunroof) .
2. Position sunroof assembly on suitable work bench.
3. Remove 4 Torx screws securing glass to sunroof frame.
4. Remove sunroof glass.
5. Release both glass carriers from cables and remove.
6. Remove 10 Torx screws securing frame to drive cable assembly.
7. Remove drive cable assembly from frame.

1. Fit drive cable assembly to frame.
2. Fit Torx screws securing frame to drive cable assembly and tighten to 2.5 Nm (1.8 lbf.ft).
3. Fit glass carriers to cables.
4. Fit glass to sunroof frame and secure with Torx screws. Do not fully tighten screws at this stage.
5. Fit sunroof. For front drive cable assembly: Refer to «SUNROOF - FRONT»(/land-rover/discovery/l318-2002-2004/remont/sun-rooft-topconvertible-top/#sunroof) . For rear drive cable assembly: Refer to «SUNROOF - REAR»(/land-rover/discovery/l318-2002-2004/remont/sun-rooft-topconvertible-top/#sunroof) .
6. Remove timing pegs supplied with drive cables.
7. Adjust position of sunroof glass in relation to sunroof panel until a 6.5 mm (0.25 in) gap is produced between the front edge of the glass and the sunroof frame.
8. Tighten sunroof glass retaining screws to 3 Nm (2.2 lbf.ft).

Scheme 22

1. Release switch pack from front stowage pocket.
2. Disconnect multiplugs from 3 sunroof switches.
3. Remove switches from switch pack.

1. Fit switches to switch pack.
2. Connect multiplugs to switches.
3. Fit switch pack to front stowage pocket.

Scheme 23

1. Remove front stowage pocket. Refer to «REMOVE»(/land-rover/discovery/l318-2002-2004/remont/exteriorinterior-trim/#interior-trim-components) .
2. Remove 2 screws securing ECU to roof.
3. Disconnect 2 multiplugs from ECU.
4. Remove sunroof ECU.

1. Position sunroof ECU and connect multiplugs.
2. Fit and tighten screws securing ECU to roof.
3. Fit front stowage pocket. Refer to «REFIT»(/land-rover/discovery/l318-2002-2004/remont/exteriorinterior-trim/#interior-trim-components) .

See also:
• REMOVE
• MOTOR - SUNROOF