Check monitoring system - AR42.50-P-0001-03MB

The ignition must be switched off.

1. Remove connection plug (1) from motor-and-pump assembly.
2. Release pressure from booster circuit (by depressing brake pedal approximately 30 times).
3. Read pressure indicated on gauge.

   Pressure gauge indicates 0 bar: System OK. Pressure gauge shows residual pressure (> 0 bar): Brake booster hydraulic unit is defective.

   Fig 1: Checking Monitoring System

   
4. Start engine. After 60 seconds the following message should appear in the instrument cluster "BRAKE SYSTEM - STOP, CALL FOR SERVICE."

   Message appears: System OK

   No message appears: ESP control unit or vehicle electrical system defective.

5. Switch off ignition.
6. Reconnect plug (1) to motor-and-pump assembly (should audibly snap into place).
   Fig 2: Identifying Instrument Cluster