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:

    Making a call
    1. Ensure that is shown at the top of the center console display and that the handsfree function is in telephone mode. 2. Dial the desired phone number using the center console keypad or use the s ...

    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 ...

    Trip odometers
    Trip odometers and reset button 1 Odometer display 2 Button for toggling between T1 and T2, and for resetting the odometer The trip odometers are used to measure short distances. A short pres ...