Preparation
Checking the hydraulic pump
3 - Air suspension control unit
3p - Drain plug on the control unit
S2 - Test setup
1. Disconnect the return line (T) from the tank (2).
2. Attach a return tube to one end of the return line and place the other end in a measuring tank.
3. Start the engine and set the idle speed.
4. Check pump flow. Pump flow 0.2 l/min.
5. Stop the engine.
6. Connect the return line (T) to the tank (2).
7. Drain the fluid from the system.
Examination
1. Connect the tester to the control box (3).
2. Fill the reservoir (2) liquid.
3. Start the engine and set the idle speed.
4. Install the lever (3a) control unit to position «filling» - F.
5. Check pump delivery pressure. Since the pressure is significant, carry out the test for a short time. The bypass valve of the control box limits the pumping pressure. The bypass valve makes a whistling sound when opened. If the relief valve opening pressure is lower than required, replace the pump. If the bypass valve opening pressure is higher, check the rear suspension control unit. Bypass valve opening pressure 120-153 bar.