Nissan Sentra/Pulsar/NX 1982-1996 Repair Guide

Idle Air Control Valve (IACV) Air Regulator

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OPERATION



See Figures 1 and 2



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Fig. Fig. 1: Cross-sectional view of the IACV Air Regulator assembly-CA16DE and CA18DE engines



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Fig. Fig. 2: Cross-sectional view of the IACV Air Regulator assembly-1991-94 GA16DE and SR20DE engines

The IACV-air regulator is used on CA16DE, CA18DE, GA16DE and SR20DE engines to provide increased idle speed during cold engine operation. The valve contains bimetal spring, that is connected to a rotary shutter. The shutter opens, when the engine is cold, allowing additional air to bypass the throttle plates, thus increasing the engine speed. During warm-up, an electrical current supplied to the valve, heats the bimetal spring, closing off the port.

TESTING



See Figures 3 and 4



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Fig. Fig. 3: Connect an ohmmeter across the air regulator terminals, as shown



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Fig. Fig. 4: Check for battery voltage at terminal A-CA18DE connector shown, others similar

  1. Turn the ignition switch to the OFF position.
  2.  
  3. Disconnect the IACV-air regulator electrical connector.
  4.  
  5. Connect a voltmeter between terminal A and a known good engine ground.
  6.  
  7. Turn the ignition switch ON . Battery voltage should be present.

    If battery voltage is present, proceed to the next step.
     
    If battery voltage is not present, check power supply circuitry.
     

  8.  

  1. Turn the ignition switch OFF .
  2.  
  3. Connect an ohmmeter from terminal B to a known good engine ground. Continuity should exist.

    If continuity is present, proceed to the next step.
     
    If continuity is not present, check ground circuit for opens.
     

  4.  

  1. Connect an ohmmeter across the IACV-air regulator terminals.
  2.  
  3. Measure the resistance between the terminals. The resistance should be approximately 70-80 ohms. If resistance is not within specifications, replace the IAC control valve
  4.  
  5. Visually inspect the rotary shutter for clogging, sticking or binding. Clean shutter or replace the valve assembly if necessary.
  6.  

 
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