Suspension: Testing and Inspection
PSM/ABS check using the PIWIS TesterTools
Test overview
Note:
^ PSM is installed as standard.
^ PSM comprises the functions ABS (anti-lock braking system), ABD (automatic brake differential), ASR (anti-slip regulation), EDTC (engine drag torque control), EBD (electronic brake-force distribution) and vehicle dynamic control.
The ABS/ PSM test includes:
^ Reading out fault memory.
^ Static test.
^ Swap testing hydraulics in the Checks/Tests menu. The swap test is menu-driven. Once you start the test, follow the instructions on the PIWIS Tester.
^ Checking function and correct allocation of speed sensor in the Actual values menu. Turn all four wheels individually during the test. The speed assigned to the wheel in question must be displayed when you turn the wheel. The non-tested wheel must be held (by a second person) when the test is performed on the driven axle.
Procedure:
If work has been done on the hydraulic unit -D-, the speed sensors and the wire harness or if the hydraulic unit -D- is replaced, an ABS/PSM test (system check) must be performed using the PIWIS Tester! This is the case, for example, after accident repairs! This prevents any confusion of electrical or hydraulic lines and ensures faultless operation of the system!
If certain brake lines are replaced, e.g. at the intermediate piece in the front left wheel housing -E-, a swap test must also be performed (in the Checks/Tests menu)! Unintentional bending of the brake lines could lead to incorrect hydraulic allocation despite the markings (FL = front left, FR = front right, RL = rear left, RR = rear right)!
If a fault is displayed during operation (when no assembly work was carried out beforehand), diagnosis and fault finding are also carried out using the PIWIS Tester! To do this, select the PSM system and read out the fault memory there! The fault can then be located using the appropriate menus (Drive links, Actual values, Checks/Tests)!
PSM check using the PIWIS Tester
1. PIWIS Tester P 9718 must be connected to the vehicle, then start it. Switch on ignition and press >> to continue. The PIWIS Tester 9718 is connected to the vehicle via a diagnostic socket. The diagnosis socket is located inside the vehicle in the vicinity of the driver's A-pillar below the instrument panel.
2. Select the vehicle type and call up the PSM system.
3. Carry out ABS/PSM test (see Test overview).