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Automatic Idle Control (AIC)

CAUTION: The following test is to be performed with engine running. Use only a high quality multimeter or approved Saab multimeter when performing voltage checks in the following steps.
  1. Ensure ECU and all control systems are properly connected. Start engine and run at normal operating temperature. Connect Green/Red wire of 3-terminal limp-home test connector to a known good ground (connector is located near evaporator housing).
  2. Remove ground wire. When wire is removed, engine RPM should increase then return to idle. If engine RPM does not respond, go to step 3). If engine RPM responds correctly, reconnect ground wire, set basic idle speed, and disconnect ground wire.
  3. Pull back rubber boot from AIC actuator plug (at actuator). Connect positive voltmeter lead to terminal 2 of connector. See Fig 1 .
    Fig 1: AIC Switch Terminal Locations
    G35437
  4. Connect negative lead of voltmeter to grounding point at engine lifting hook. Start engine and check voltage reading. Meter should indicate battery voltage.
  5. Connect positive voltmeter lead to terminal 2 of connector. Connect negative lead to terminal 3 of connector. Verify that voltage reading and idle speed change as A/C system is turned on and off (actual voltage reading is not important).
  6. Turn off engine. If voltage and idle speed changed as specified, system is okay. If voltage changes but idle speed does not, go to next step. If voltage does not change, go to step 8).
  7. Check all AIC system hoses for cracks and/or leaks. Disconnect AIC actuator plug (at actuator). Check resistance through actuator windings by measuring resistance between actuator terminals 1 and 3. Resistance should be 36-44 ohms. Replace actuator if defective, and retest system. Reconnect harness plug to AIC actuator.
    NOTE: Ignition must be off when connecting or disconnecting the ECU. Remove wiring harness connector from ECU, prior to testing. Repair any problems as they are found, before proceding to next step in test procedure. Always probe from rear of connector to avoid enlarging connector pin holes.
  8. Disconnect ECU harness connector. Check continuity between ECU harness connector terminals 10 and 23. See Figure . Resistance should be 36-44 ohms. If resistance is incorrect, go to step 10).
  9. If resistance is correct and problem still exists, substitute a new ECU, connect ECU harness connector, and recheck system operation. Proceed to FUEL INJECTION BASE LINE VALUE adjustment.
  10. Check for battery voltage at ECU harness connector pin 16 when A/C compressor is engaged. If resistance is correct and problem still exists, substitute a new ECU, connect ECU harness connector, and recheck system operation.
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