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Home >> Saab >> 1990 >> 900 SPG, Automatic >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - System/Component Tests >> Idle Control System >> Auxiliary Air Valve
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Auxiliary Air Valve

  1. Connect tachometer to engine. Start and warm engine to normal operating temperature. Turn A/C on and check engine RPM. Engine speed should initially decrease and return to normal idle speed.
  2. If RPM did not return to normal idle speed, check for battery voltage at auxiliary air valve harness connector. If voltage is present, check resistance between auxiliary air valve terminals. Resistance should be 40-60 ohms. Replace auxiliary air valve is resistance is not as specified. If voltage was not present, go to next step.
  3. Check Red wire between power distribution panel (A/C relay) and auxiliary air valve through the connector in engine compartment. Check Black ground wire. If wiring is okay, check operation of A/C relay.
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