Test steps 12-19

In the Drive links menu, check the inlet and outlet ABS solenoid valves in the hydraulic unit for function and incorrect allocation.  Rotate all four wheels individually (one after the other according to the test-step sequence). When doing this, carefully follow the instructions in the Tester Display.

On the Solo ABS, the test of the rear-axle valves (test steps 16 and 17) can be performed on the right or left wheel.

1. Test step 12: Maintain pressure, front left 
2. Test step 13: Reduce pressure, front left 
3. Test step 14: Maintain pressure, front right 
4. Test step 15: Reduce pressure, front right 
5. Test step 16: Maintain pressure, rear left (or rear with Solo ABS) 
6. Test step 17: Reduce pressure, rear left (or rear with Solo ABS) 
7. Test step 18: Maintain pressure, rear right 
8. Test step 19: Reduce pressure, rear right 

Test steps 18 and 19 ONLY on vehicles with TC.

Test step "Maintain pressure" not OK: 

• Hydraulic lines incorrectly allocated if the activated wheel locks up (precondition: Inlet valve activated with the F8 key). Incorrect allocation of electrical wires is another possibility if impermissible repairs were made on the wiring harness after accident repairs.
• Inlet valve faulty.

Test step "Reduce pressure" not OK: 

• If the activated wheel does not  alternately lock up and then rotate freely again but another wheel does this (precondition: the parking brake is not engaged and the selector lever of Tiptronic vehicles is in position "N"), the hydraulic lines are swapped.
• Outlet valve defective.

Troubleshooting 

Perform troubleshooting analogous to Test point 10  .