Idle Speed Control: Notes

NOTE: For other input components in idle speed circuit, see INPUT DEVICES under COMPUTERIZED ENGINE CONTROLS.

Idle speed is controlled by Idle Air Control (IAC) valve and fast idle thermo valve. IAC valve controls amount of air into the intake manifold, according to input signals received from the PCM. The following PCM inputs have influence on IAC valve operation and idle speed:

A/C Clutch Signal
Alternator FR Signal
A/T Gear Position
Brake Switch
Engine Coolant Temperature Sensor
Power Steering Pressure Switch
Starter Switch Signal.