Pneumatic Locking/Unlocking, Function

Pneumatic Distribution:

The electric motor driven dual pressure pump is integrated into the PSE control module (combined) (A37). It provides vacuum or pressure depending on the polarity of the operating voltage. The distribution to the various actuators is accomplished by means of 3/2-way valves.

Global unlocking:
The dual pressure pump supplies pressure. Solenoid valves 1 and 2 are not switched so that all doors are unlocked, then solenoid valve 2 switches unlocking the tank flap.

Selective unlocking:
The dual pressure pump supplies pressure. Solenoid valve 2 is switched, solenoid valve 1 is not actuated. This unlocks the driver's door and tank flap.

Locking:
The dual pressure pump supplies vacuum. Solenoid valves 1 and 2 are not switched so that all doors are locked. Then solenoid valve 2 switches and the tank flap is unlocked.

Opening trunk lid
The dual pressure pump supplies pressure. Solenoid valve 1 is switched so that the trunk lid lock is opened when it is not secured by the locking cylinder in the 90° position.

Retractable rear head restraints (RHR)
The dual pressure pump supplies vacuum. Solenoid valve 1 is switched. The rear head restraints pivot to the rear (not on model 208.4).