Procedures
51 24 ... Instructions For Automatic Rear Lid Actuation(Electrohydraulic/Fully Automatic)
CAUTION:
- When working on the opened hydraulic system:
- Adhere to the utmost cleanliness.
- Even the smallest of dirt particles in the hydraulic system can cause malfunctions.
Opening and closing rear lid:
Actuation of rear lid is only possible via
NOTE: If a control button is operating again during an opening or closing procedure, this procedure is stopped. When operated again, this changes the direction of the rear lid (except passenger compartment button, opening only here).
Anti-repeat device:
An anti-repeat device is fitted to prevent the hydraulic control unit from overheating.
The total motor running time of the hydraulic control unit is recorded by a counter. If the motor is not activated, this counter is reduced by a third of the pause time. A new actuation will not be accepted if the counter exceeds a total running time of 2 minutes. Thus, for a motor running time exceeding 2 minutes, an enforced pause which is three times as long is engaged.
After a cooling-down period of 6 minutes, it is again possible for the motor to run for 2 minutes.
NOTE: However, an actuation which is in operation is not terminated even if the maximum running time is exceeded.
Installation location of individual hydraulic parts:
Hydraulic cylinder:
The hydraulic cylinder (2) is located on the left rear lid hinge between the gas spring struts for rear window (3) and rear lid (1).
Trunk lid module and hydraulic control unit:
The hydraulic unit is located on the left side in the luggage compartment in the spare wheel recess and to the left of it is the rear lid module.
The hydraulic unit is activated by the rear lid module.
A tilt sensor is fitted underneath the rear lid trim, refer to Removing tilt sensor for automatic rear lid actuation.
Emergency rear lid operation:
If the automatic facility fails, the rear lid can be opened and closed manually without the need for supplementary measures.
The force need for emergency operation is greater.
Emergency operation is determined by:
- the switching pressure of the emergency valve (mechanical/hydraulic pressure limiting valve),
- the fluid is forced out of the lines during the first two actuations and
- the friction by the hydraulic cylinder from the third actuation.
Safe stopping in an open position is assured in an opening angle range of 30° to 90°. This is achieved by a minimum system pressure of 40 bar (determined by the emergency valve).
Checking fluid level in hydraulic unit:
CAUTION:
- In the event of fluid loss, the hydraulic unit must be replaced if the fluid is below the marking because damage to the unit cannot be excluded.
- Hydraulic unit together with cylinder and lines must be replaced:
- If, in the event of rear end damage, the spare wheel recess is defective and the line connections are bent.
Remove luggage compartment floor trim panel.
Test conditions:
Open trunk lid (by motor) once and then close again so as to bleed the system.
Open trunk lid again (by motor).
Unscrew nuts (1).
Remove car jack (2) and wedge (3).
Unscrew nuts (1).
Remove storage tray (2).
Remove spare wheel (3).
Unfasten plug connection (1).
Loosen screw (2).
Unscrew nuts (3).
NOTE:
- Illustrations show retaining plate removed for purposes of clarity.
- Place hydraulic unit on a flat, level surface with drive (1) facing upwards.
Test requirements:
Open trunk lid (by motor) once and then close again so as to bleed the system.
Open trunk lid again (by motor).
When cylinder is fully extended (rear lid open), fluid level must be in region (A) of marking (2) on hydraulic unit.
Topping up fluid in hydraulic unit:
NOTE: Topping up of hydraulic fluid is only possible on hydraulic units (1) fitted with a filler plug (2).
If necessary, remove and install hydraulic unit for rear lid actuation (electrohydraulic/fully automatic), refer to Checking fluid level in hydraulic unit.
Unlock plug housing (1) and detach from retaining plate (3).
Slacken nuts (2) and detach retaining plate (3) from hydraulic unit (4).
Open oil filler plug (2) on hydraulic unit (1). Add as much hydraulic fluid (sourcing reference: BMW Parts Service) until it reaches area of marking.
Installation:
Fit a new oil filler plug (2) and seal.
2AZ Oil filler plug to hydraulic unit 8+2 Nm
Check fluid level again.
Sealing connections on hydraulic unit and hose connections for hydraulic cylinders:
Sealing hydraulic unit:
Use the seal plugs from the kit Banjo bolts for hydraulic unit* and the old seals.
Installation:
1AZ Banjo bolt to hydraulic unit and to hydraulic cylinder 10+2.5 Nm
Sealing hose connections:
Use the seal plugs with cap nuts from the kit Banjo bolts for hydraulic cylinders* and the old seals.