System Check (ABS and ABS/ABD): Overview

System check (ABS and ABS/ABD) Important notes

1. If work is carried out on the hydraulic unit, the speed sensors and the wiring assembly or if components and ancillaries are replaced, a system check (operational check) must be run. This may be required, for example, after performing accident repairs. This check avoids any accidental interchanging of electrical wiring or hydraulic piping and ensures perfect system operation. A system check should also be run after replacing certain brake pipes, e.g. on the adapter (near the upper left of the spare wheel well). Inadvertent bending of the brake pipes may result in incorrect hydraulic connections even though the pipes have different threads (M12 x 1 and M 10 x 1).

2. The system check is menu-controlled (program-controlled). It is therefore not possible to return to the previous test step! The test period per test step is, in some cases, limited to 30 seconds. If the test period is exceeded, the following fault message is displayed: Test stage (with corresponding No.) not O.K.. In this case, the system check has to be repeated from the start. Before starting the system check, the static test is executed automatically. The system check is not released until the static test has been completed successfully.

3. Since vehicles with solo ABS (without ABD) require less test steps (as some components are not fined), the solo ABS system check bypasses the test steps related to ABD. On solo ABS systems, the system check is completed after test step No.20 has been executed (ABS/ABD = 26 test steps).

4. Test drive the vehicle after completing the system check, making sure that a controlled braking operation (with ABS control) is performed at least once during this test drive.

System check overview (ABS and ABS/ABD)

Note

If a particular test step is found to be not o.k. during the system check, locate and remedy the fault according to the below overview. Before starting the troubleshooting procedure, make sure that the fault is actually a system fault and is not caused by incorrect operation. Example for incorrect operation: If a procedure displayed on the tester display is not run correctly or if an incorrect key is pressed inadvertently, the message ,,Test stage (with No.) not O.K. Remove cause!" is displayed.