Nissan Maxima 1993-1998 Repair Guide

Idle Air Control Valve

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OPERATION



The Idle Air Control Valve-Auxiliary Air Control (IACV-AAC) functions by using a duty cycle (on/off/on), which is controlled by the ECM. The longer the "on" pulse, the greater the amount of air that will flow through the valve. The more air that flows through the valve, the higher the engine speed. Actual idle speed is the lowest speed at which the engine can operate steadily. This is computed by the ECM, taking into consideration various conditions such as warm-up, deceleration and engine load.

TESTING



See Figures 1 and 2

  1. Disconnect the electrical harness from the valve.
  2.  



Click image to see an enlarged view

Fig. Fig. 1: Push in the tab on the connector and pull back to remove the IACV-AAC valve connector

  1. Measure the resistance between the terminals of the valve.
  2.  



Click image to see an enlarged view

Fig. Fig. 2: The resistance of this IACV-AAC valve confirms proper operation

    1. 1993-94 VG30E engines: 0.5 ohms
    2.  
    3. 1993-94 VE30DE engines: 10 ohms
    4.  
    5. 1995 VQ30DE engines 0.5 ohms
    6.  
    7. 1996-98 VQ30DE engines should be around 30 ohms 77°F (25°C)
    8.  


  1. If resistance is not within specification, the valve may be faulty.
  2.  
  3. If resistance is within specification, check the circuits back to the ECM.
  4.  

REMOVAL & INSTALLATION



See Figure 3

  1. Disconnect the electrical harness from the valve.
  2.  
  3. Remove the valve attaching bolts.
  4.  
  5. Remove the valve from the assembly.
  6.  



Click image to see an enlarged view

Fig. Fig. 3: Make sure the plunger slides smoothly inside the housing

It may be easier to remove the IACV by removing the entire IAA unit from the manifold.

To install:
  1. Install the valve on the assembly.
  2.  
  3. Tighten the attaching bolts securely.
  4.  
  5. Connect the electrical harness to the valve .
  6.  

 
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