2. To check the correct functioning of the system, start the engine and slightly raise its speed to 3000 rpm, observing the reaction of the power valve actuator. The stem of the actuating device should extend or retract accordingly when changing speed, otherwise turn off the engine, proceed to the next step of the test.
3. Check the condition of the vacuum hoses from the vacuum source to the power valve actuator. Check the tightness of the vacuum reservoir.. make sure. A one-way valve only allows air to flow in one direction.
4. Disconnect the electrical wiring from the power valve control solenoid valve. Turn the ignition on and use a voltmeter to check for battery voltage at the white/blue wire terminal of the connector harness. If there is no voltage, check the condition of the wiring in the section of the circuit between the connector and the fuse mounting block. Check for an open in the orange wire from the connector to the PCM.
5. Disconnect the vacuum lines from the control solenoid valve fittings. Using a pair of fused jumper wires, apply battery voltage directly to the two terminals of the solenoid valve - a distinctly audible click should be heard, while air should begin to flow freely between the two fittings of the assembly. Disconnect the jumper wires - the passage should be blocked. A defective control solenoid valve must be replaced.
6. Disconnect the vacuum hose from the power valve actuator and connect a hand vacuum pump instead. Create a vacuum on the actuator, the pusher rod must move, ensuring complete tightness of the assembly, otherwise replace the actuator.
7. If during the checks carried out it was not possible to reveal any deviations, the car should be driven to a service station for a detailed diagnosis of the condition of the PCM and the corresponding refurbishment.