Check reservoir preload - AR42.50-P-0001-04MB

The ignition must be switched off.

1. Release pressure from booster circuit (depress brake pedal approximately 30 times). Pressure gauge should indicate 0 bar.
2. Switch on the ignition and simultaneously note the reading on the pressure gauge. The following message appears in the instrument cluster: "BRAKE SYSTEM - WAIT - PRESSURIZATION".

   When the ignition is switched on the pressure should jump from 30 to 85 bar. This is the reservoir preload.

   Pressure between 30 and 85 bar: System OK.

   Pressure below 30 bar: Malfunction in reservoir motor-and-pump assembly and reservoir for brake booster hydraulic unit.

   Fig 1: Checking Reservoir Preload