Diagnostic Aids

Any condition that can affect engine performance at idle, can affect performance of the IAC system. A careful visual and/or physical inspection of the engine is necessary when the scan tool indicates engine speed or IAC Motor Command readings are out of range. An intermittent IAC system concern may be caused by poor electrical connections in the IAC valve circuits. Thoroughly check any circuitry that is suspected of causing an intermittent condition. See INTERMITTENTS in TROUBLE SHOOTING - NO CODES - 1.8L VIBE article.