Preconditions

^ Before the test work, connect the brake bleeding equipment.
^ Release the pressure in the hydraulic system before any work. To do so, turn the ignition off, open the bleeder valve SP (on the ABS/ASR hydraulic unit) and let the pressure reserve contents flow into a container.
^ After the test work, first conduct the pressure reservoir charging process (plug in the ABS/ASR control unit and start the engine). Let the engine run until the the pressure reservoir is full, about 1 minute. Then top off the fluid level in the brake fluid reservoir.
^ TEST STEP 1: The prescribed tolerance of the pressure valve (1.8 to 11 bar or 26.1 to 159.50 psi) is dependant on the production tolerances in the charging pump, the ABS/ASR hydraulic unit and the return check valve of the pressure reservoir.
^ TEST STEP 2: If the Return/Pressure Pump is defective there will be no pressure increase or it will take longer than 60 seconds. If the pressure reservoir is defective, the pressure either rises quickly to 50 bar (725 psi) and then slowly up to the maximum pressure, or quickly and constantly up to the maximum pressure.