Test 10 - Hydraulic Unit, Pressure Build-up, Pressure Hold

TEST SEQUENCE
1. Connections needed:
- T-plug (4a) with adapter (A) at Antilock Brake System (ABS) wire harness (1)
- T-plug (4b) at ABS control unit (2)
- Connecting lead at adapter (A) to cigarette lighter - red telltale lamp comes "On"
2. With front axle on BPS and "*" flashing on tester, set to FRONT L/R at down arrow button.
3. Switch "On" ignition. Note voltage between leads 1 and 10 (run engine at idle speed if nec.). Switch "On" BPS for both wheels.
4. Apply brakes until BPS reading is 2000 N or 1500 N (charge axle if nec.), and maintain this pedal force steadily.
5. Press acknowledge button. After 2 sec. the pump will cut in, the valve will be opened for approx. 4 sec. and moved to the retention phase after a short period of pressure buildup, and the 's' display will start run. When 5 sec. are displayed, press the acknowledge button.
6. To repeat, press acknowledge button. To move on to next wheel, press down arrow button. Test positions: FRONT L/R REAR L/R in any desired order.





Nominal Values

7. Compare the displayed actual values obtained from the test equipment with the nominal values provided above. If nominal values are not obtained, proceed with the troubleshooting procedures below as needed.

TROUBLESHOOTING
Voltage Between Wires 1 And 10
- Turn on ignition.
- Run engine.

Battery charged (check).

Front Left, Right, Left/right - Rear Left, Right, Left/right
- Due to high switching on power, possibly repeat test step with engine running. Refer to test steps 05/06/07.
- Testing the ABS requires the conventional brake system to be okay: bled properly, brake line connections tight, brake pads okay.
- Watch uniformity of wheels on one axle.

Replace hydraulic unit.