Power valve operation control system (Nissan Maxima A32)

1. The power valve is provided on 1993 and 1994 models. The system consists of a power valve placed inside the intake manifold), an actuator, a control solenoid valve and a PCM. The power valve controls the direction of the intake air flow. At low engine speeds, the vacuum created in the intake manifold acts on the power valve actuator, which leads to the latter being closed, while the air sucked into the engine moves along a longer path, which provides for an increase in engine torque at low speeds. When the engine speed reaches a certain value, the PCM cuts off power to the control solenoid valve, which leads to a violation of the actuator's tightness and closing of the power valve. In this case, air begins to be sucked into the engine along a shorter path, which increases the efficiency of the power unit at high speeds.

2. To check the proper functioning of the system, start the engine and slightly increase its rotation speed to 3000 rpm, observing the reaction of the power valve actuator. The actuator rod should extend or retract accordingly when the speed changes, otherwise, turn off the engine and proceed to the next stage of the test.

3. Check the condition of the vacuum hoses running from the vacuum source to the power valve actuator. Check the tightness of the vacuum reservoir.. make sure that the one-way valve only allows air to pass in one direction.

4. Disconnect the wiring from the power valve control solenoid. 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 wiring between the connector and the fuse box. Check for an open in the orange wire from the connector to the PCM.


5. Disconnect the vacuum lines from the solenoid control valve fittings. Using a pair of fused jumper wires, apply battery voltage directly to the two terminals of the solenoid valve - you should hear a distinct audible click and air should begin to flow freely between the two fittings of the assembly. Disconnect the jumper wires - the passage should be blocked. A faulty solenoid control 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 push rod should move, ensuring complete sealing of the assembly, otherwise replace the actuator.

7. If no deviations are found during the checks, the vehicle should be taken to a service station for a detailed diagnosis of the PCM condition and appropriate repairs.

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