Leak test
Apply 12V to the plugs «2» And «3» servo connector (polarity doesn't matter). In this case, the vacuum valve should switch with a characteristic click.
Connect tester (in ohmmeter mode) to plugs «4» And «7» servo connector.
Connect the hand vacuum pump hose to the «A» servo. Create a vacuum at which the resistance value will be 500-700 ohms (at the same time, the pusher of the servo drive is not fully retracted). The plunger is fully retracted at a vacuum of approx. 250 mbar.
Disconnect the electrical wires from the servo connector, then disconnect from the nozzle «A» vacuum pump hose and take the tester readings - within 1 min, the resistance should increase by no more than 200 ohms. If the resistance has increased by a large amount, replace the servo.
Apply 12 V again to the plugs «2» And «3» servo connector and read the tester. If the resistance value increases by more than 650 ohms in 5 seconds, replace the check valve.
Fully retract the servo plunger by applying a vacuum of about 250 mbar.
Apply 12V to the plugs «2» And «8» servo connector (polarity doesn't matter). At the same time, the atmospheric valve should switch with a characteristic click, and the pusher of the servo drive should move forward in 1 s.
If the pusher extends for a longer time or does not extend. check the vacuum valve hose, the condition of the electrical wires and the air filter of the 1st chamber throttle servo. Replace the filter or the servo itself if necessary.
Note. When supplying voltage to the servo connector directly from the battery, it is recommended to include a 1-5 A fuse in the supply wire circuit.