There are a multitude of solenoids used by the ECU to control various engine functions.  There are five control soleniods (labels with "round" colored stickers) located by the oil filler neck.  These are labelled 1 though 5 (located in the lower right-hand corner of this diagram):
Click here for vacuum hose diagram and general solenoid location


1 Twin scroll turbocharger solenoid valve "Controls exhaust flow area"

Controls vacuum actuation of twin scroll for turbo

Solenoid switched on over 2,700RPM.
(LB) terminal voltage:
  • below 2,700RPM:  below 2.0VDC
  • Above 2,700RPM:  ~12.0VDC

    Note:  solenoid is Normally-Open (Bypass) type.
    • 2 Switching solenoid valve "Controls switching valve on the air control valve"

    Solenoid switched off at idle or deceleration.
    Solenoid switched on above 4,200RPM or acceleration.

    Note:  solenoid is Normally-Closed type.
    3 Pressure regulator control solenoid valve "Shuts vacuum passage between dynamic chamber and pressure regulator
    - only during hot condition"

    Controls vacuum routing for actuation of two-stage fuel pressure regulator
    on hot-start

    Solenoid terminal voltage:
  • First 50 seconds:  below 2.0VDC
  • After 50 seconds:  ~12.0VDC

    Note:  solenoid is Normally-Closed type.
    • 4 Relief solenoid valve "Controls relief valve"

    Controls vacuum routing for actuation of port in Air Control Valve (ACV)

    Solenoid switched off at idle or deceleration.
    Solenoid switched on above 3,750RPM.

    Note:  solenoid is Normally-Closed type.
    5 EGR valve "Supplies intake manifold to EGR valve"

    Controls vacuum routing for actuation of EGR valve

    Note:  solenoid is Normally-Open (bypass) type.


    These solenoids generally do not fail.  If they do fail, you need to replace them with another Mazda OEM solenoid.



    Questions?  Comments?  Send mail to:  reted@fc3spro.com

    02/02/2004