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Home >> Jeep >> 1994 >> Wrangler S, Automatic >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - System/Component Tests >> Idle Control System >> Idle Air Control (IAC) Motor
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Idle Air Control (IAC) Motor

  1. Set parking brake and block drive wheels. Route all Exerciser Tester (7558) cables away from cooling fans, drive belt, pulleys, and exhaust components. Return engine idle speed to normal before disconnecting exerciser.
  2. With ignition off, disconnect IAC motor connector at throttle body. Plug in exerciser tester harness connector into IAC motor. Connect Red clip of exerciser to battery positive terminal.
  3. Connect Black clip to battery negative terminal. Red light on exerciser will flash if exerciser is properly connected. Start engine. Move exerciser switch to HIGH position. Engine speed should increase. Move switch to LOW position. Engine speed should decrease.
  4. If engine idle speed changes while using exerciser, IAC motor is working properly. Return engine speed to normal idle and disconnect exerciser from IAC motor.
  5. If engine idle did not change, turn ignition off. DO NOT  disconnect exerciser from IAC motor. Remove IAC motor from throttle body. With ignition off, cycle the exerciser switch between HIGH and LOW positions. Pintle should move in and out of motor.
    CAUTION: When checking IAC motor operation with motor removed from throttle body, DO NOT  extend pintle more than 1/4" (6.35 mm), as pintle may separate from motor. The IAC motor must be replaced if pintle separates from motor.
  6. If pintle still does not move, replace IAC motor. Start engine and test replacement motor. If pintle now operates properly, check IAC motor bore in throttle body and clean if necessary. Reinstall IAC motor and retest.
  7. If throttle body is clear of obstructions, USE A Chrysler Corp. Diagnostic Readout Box II (DRB-II) tester and refer to appropriate IAC motor tests in TESTS W/CODES - 2.5L & 4.0L article in this section.
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