Checking check valve - AR43.10-P-0023CW
Eliminate the vacuum in brake booster (A7/7). To do this, press the brake pedal several times with the engine switched off.
Open engine hood and raise to vertical position.
Connect vacuum tester (030) to brake booster (A7/7) with test connection (031). See AR43.10-P-0024-01V . Special tools 201589132100 168589086300, see Figure.
Start the engine and produce a vacuum of 0.75 to 0.8 bar by pressing and suddenly releasing the accelerator pedal. Reduce vacuum >0.8 bar by depressing the brake pedal several times.
Turn off engine. The vacuum must not reduce by more than 0.2 bar within 30 seconds. In the event of a vacuum loss >0.2 bar: Replace vacuum line (8) with check valve (17). If necessary: Check brake booster. See AR43.10-P-0325CW .