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Home >> Saab >> 1991 >> 900 Base, 2D Convertible, Automatic >> Repair and Diagnosis >> Engine Performance >> Testing & Diagnosis >> Engine Controls - System/Component Tests >> Idle Control System >> Engine Controls - System/Component Tests >> Automatic Idle Control (AIC)
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Automatic Idle Control (AIC)

  1. Connect ISAT Scan tester according to manufacturer's instructions. Diagnostic connector is under right front seat, protected by a plastic cover. Turn ignition on. Enter command code 553. Listen for sound from AIC valve, located on intake manifold.
  2. If no sound, leave ignition on. Check that battery voltage is available at pin No. 2 (Blue/Red wire) on AIC valve. If no voltage, repair Blue/Red and Green/White wires to pin No. 87 of main relay.
  3. Turn ignition off. Unplug connector from AIC valve. Measure resistance between pins No. 1 and No. 2 (Blue/Red and Blue/White wires on mating connector).
  4. Measure resistance between pins No. 2 and No. 3 (Gray/Red wire on 900 Series; Green/Gray wire on 9000 Series) and Blue/Red wires on mating connector. Replace AIC valve if resistance is not 10-15 ohms for each measurement.
  5. With ignition off, check Blue/White wire between AIC valve connector and pin No. 33 on fuel injection ECU for open or short circuit. Repair wire if defective.
  6. With ignition off, check Gray/Red (900 Series) or Green/Gray (9000 Series) wire between AIC valve connector and pin No. 15 on fuel injection ECU. Repair wire if it is shorted or open.
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