Power brakes function only when theengine is running

Power brakes function only when theengine is running  - Brake system - Starting and driving - Volvo XC90 Owners Manual - Volvo XC90

The power brakes utilize vacuum pressure which is only created when the engine is running.

Never let the vehicle roll to a stop with the engine switched off.

If the power brakes are not working, considerably higher pressure will be required on the brake pedal to compensate for the lack of power assistance. This can happen for example when towing your vehicle or if the engine is switched off when the vehicle is rolling. The brake pedal feels harder than usual.

    See also:

    Installing the cover
    1. Press the end piece on one side of the cargo area cover into the retaining bracket in the side panel of the cargo area 1. 2. Do the same on the opposite side 2. 3. Press both sides of the cov ...

    Introduction
    Your vehicle is equipped with tires according to the vehicle's tire information placard on the B-pillar (the structural member at the side of the vehicle, at the rear of the driver's door ...

    Rear window and door mirror defrosters
    Use the defroster to quickly remove fog and ice from the rear window and the door mirrors. Press the button once to start simultaneous rear window and door mirror defrosting. The light in the ...