Idle Speed/Throttle Actuator - Electronic: Description and Operation

Idle Speed Control System:

PURPOSE
System controls amount of bypass air through the throttle body to improve startability, warm-up, idle smoothness, and driveability. This system replaces dashpot deceleration control used on previous models.

LOCATION
Bypass air control valve is on top of throttle body.

OPERATION
Bypass Air Control Valve (BAC) consists of a PCME controlled idle air control valve and an air valve that opens and closes according to engine coolant temperature. The air valve is open on cold start and closes by the time operating temperature is reached. The idle air control valve is PCME controlled to allow bypass air compensation according to a number of inputs (engine temperature, load from P/S, A/C, and A/T).