AutoZone 1990 Toyota Corolla 1.6L EFI DOHC 4cyl | Repair Guides | Driveability & Emissions Controls | Electronic Engine Controls | Air Bypass Solenoid Valve | AutoZone.com

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    Ford Aerostar 1986-1997 Repair Guide

    Air Bypass Solenoid Valve

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    OPERATION



    See Figure 1

    The air bypass solenoid or idle air control valve is used to control the engine idle speed. This component is operated by the electronic control module. The valve allows air to pass around the throttle plates in order to control cold engine idle and promote easier starting and dashpot operation.



    Click image to see an enlarged view

    Fig. Fig. 1: Bypass valve and gasket

    TESTING



    1. With the ignition in the ON position, use a multimeter and check for current at the valve. The meter should register approximately one volt.
    2.  
    3. Connect a tachometer using the manufactures's instructions.
    4.  
    5. With the engine running at normal operating temperature, apply 12 volts to the valve and watch the tachometer.
    6.  
    7. If the bypass valve is functioning correctly, the idle speed will increase 700-1000 rpm. If the idle speed does not change, or increases less than 500 rpm, replace the bypass valve.
    8.  

    REMOVAL & INSTALLATION



    See Figures 2, 3, 4, 5, 6 and 7



    Click image to see an enlarged view

    Fig. Fig. 2: Bypass solenoid attached to the throttle body-4.0L shown



    Click image to see an enlarged view

    Fig. Fig. 3: Remove the plastic cover over the throttle linkage and bypass solenoid, if equipped



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    Fig. Fig. 4: Unfasten the wire harness attached to the bypass solenoid



    Click image to see an enlarged view

    Fig. Fig. 5: Remove the retainer bolts securing the bypass solenoid in place



    Click image to see an enlarged view

    Fig. Fig. 6: Lift the bypass solenoid off ...



    Click image to see an enlarged view

    Fig. Fig. 7: ... and remove the gasket

    When the battery cable has been disconnected and reconnected, some abnormal drive symptoms may occur while the powertrain control module relearns its adaptive strategy. The vehicle may need to be driven 10 miles (16 km) or more to relearn the adaptive strategy.

    1. Disconnect the negative battery cable.
    2.  
    3. Access the idle air control valve on the side of the throttle body, and disconnect the wire harness attached to it.
    4.  
    5. Remove the two Torx® bolts securing the bypass valve into position. Lift the valve off and remove the gasket from the base of the bypass valve. Clean any excess gasket material from both mating surfaces.
    6.  

    To install:
    1. Position a new gasket on the base of the bypass valve and attach to the throttle body using the two Torx® bolts. Tighten the bolts to 8-10 ft.lbs. (10-13 Nm).
    2.  
    3. Fasten the wire harness to the bypass valve.
    4.  
    5. Connect the negative battery cable.
    6.  

     
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