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Home >> Subaru >> 1991 >> XT Standard >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - System/Component Tests >> Idle Control System >> Auxiliary Air Valve (1.2L PFI & 1.8L)
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Auxiliary Air Valve (1.2L PFI & 1.8L)

  1. With engine running, pinch hose between Auxiliary Air Valve (AAV) and intake manifold. Engine speed should drop (about 100 RPM with engine warm, more with engine cold). Release hose. Ensure engine speed returns to previous speed.
  2. If RPM is not as specified, turn ignition off. Check AAV resistance. If reading is either zero or infinity, replace AAV. Check AAV solenoid for any short to ground. If present, replace solenoid.
  3. Check for voltage at harness connector. Ensure 12 volts are available at Blue wire of AAV electrical connector. If not, check main relay, fuses and power source.
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