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Home >> Pontiac >> 1992 >> Firebird Formula, 5.0 F, Standard, M39 >> Repair and Diagnosis >> External Pages >> Different car >> Section 11 (Engine Controls - System/Component Tests) >> Idle Control System (C-2) >> Engine Controls - System/Component Tests >> Idle Air Control (IAC) Motor

Idle Air Control (IAC) Motor

WARNING: This page does not describe the selected car, but rather 34 other vehicles, including the 1991 Pontiac Sunbird, 1991 Pontiac Grand Prix, 1991 Pontiac Grand Am, 1991 Pontiac Firebird, and 1991 Pontiac Bonneville. 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" and "B" (B coil) and "C" and "D" (A coil). Resistance should be 40-80 ohms. See Fig 1 . If resistance is as specified, 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: Additional testing of Idle Air Control (IAC) motor requires an IAC motor actuator and node light, or a "Scan" tester capable of cycling ECM output devices (General Motors Tech 1).
Fig 1: Typical IAC Motor Circuit
G91E07428Courtesy of GENERAL MOTORS CORP.
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