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Idle Air Control (IAC) Motor

WARNING: This page does not describe the selected car, but rather 35 other vehicles, including the 1992 Pontiac Trans Sport, 1992 Oldsmobile Silhouette, 1992 Oldsmobile Bravada, 1992 GMC Yukon, and 1992 GMC Vandura Special. However, it is still accessible from the selected car via links, so may be relevant.
  1. Disconnect harness connector to motor. Check resistance across IAC coil terminals "A" to "B" and "C" to "D". See Fig 1. Resistance should be 40-80 ohms. If okay, go to next step. If resistance is not as specified, replace IAC motor.
  2. Check resistance between IAC terminals "B" to "C" and "A" to "D". Resistance should be infinite. If resistance is not as specified, replace IAC motor
NOTE: Functional testing of Idle Air Control (IAC) motor requires a scan tester capable of cycling ECM output devices (bidirectional) or a special IAC Driver and Node Light Set (222L or J-37027). Flow charts in the G - TESTS W/ CODES articles may refer to the Tech 1 tester, General Motors' bidirectional tester.
Fig 1: Identifying IAC Motor Circuits (Typical)
G90H15740Courtesy of GENERAL MOTORS CORP.
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