Possible causes, elimination, notes
The System Tester 2 can be used to determine whether the valve relay has picked up or dropped out. Select "Valve relay" in the Input signals menu. "Valve relay picked up" or "Valve relay dropped out" then appears in the Tester display.
Required display: Valve relay picked up.
If the control module connector was pulled off, first switch off the ignition before the test and then switch it on again, as the valve relay will otherwise not pick up.
The valve relay also can be in the dropped-out state if there is another system fault. (ABS valve fault.)
The complete hydraulic unit with integrated valve relay must be replaced if the valve relay is damaged.
Important: Before replacing the hydraulic unit, check whether:
- ground is connected to control module connector PIN 16 (from ground point 2) and PIN 19 (from electronics ground). The locations of the ground points are shown on the wiring diagram Ground points.
- plus (vehicle voltage) is connected to control module connector PIN 17 and PIN 18.
- If all test steps are OK, replace the hydraulic unit.