Idle Speed & Mixture

NOTE: Idle mixture is controlled by SBEC. No adjustment is possible.

Electronically fuel injected vehicles use an Automatic Idle Speed (AIS) motor to regulate idle RPM. The AIS is controlled by the Single Board Engine Controller (SBEC) which uses information received from various sensors to determine, among other things, idle speed. Curb idle speed is not adjustable. See appropriate TESTS W/CODES article for diagnosis of incorrect idle speed.