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:

    Getting Around
    The C30 is a fun car to drive. It has a 227-horsepower, turbocharged five-cylinder engine that makes 236 pounds-feet of torque, which is a lot of power for such a small car. It's estimated to get ...

    Safety
    Like all Volvo models, the XC90 features a comprehensive safety package designed to protect occupants in a wide variety of accidents. Given the higher centre of gravity of an SUV, however, there h ...

    Heated front seats
    The current seat temperature is shown in the center console display Press the button once for the highest heat level – three indicator lights come on. Press the button twice for a lower heat l ...