Idle Speed/Throttle Actuator - Electronic: Description and Operation

Fig. 13 Idle Air Control Motor:

IDLE AIR CONTROL MOTOR-PCM OUTPUT
The idle air control motor is mounted at the front right of the intake manifold (Fig. 13). The motor controls air flow through a passage connected to both intake manifold plenums. The PCM operates the idle air control motor. The PCM adjusts engine idle speed through the idle air control motor to compensate for engine load or ambient conditions.

The idle air control motor pintle protrudes into a housing connected to the idle air passage. The pintle controls air flow through the intake manifold while the engine idles. By extending or retracting the pintle, the PCM controls adjusts idle speed for different operating conditions.

The PCM adjusts the idle air control motor based on inputs it receives. The inputs affecting idle speed include throttle position, crankshaft position, engine coolant temperature, plus brake switch and air conditioning request signals. By increasing airflow when the throttle blade closes quickly at road speeds, the PCM prevents deceleration die out.

CIRCUIT OPERATION
The Powertrain Control Module (PCM) operates the idle air control motor through 4 circuits - K39, K40, K59, and K60. Each circuit connects to separate cavities in the PCM connector.
- Circuit K39 connects to cavity A19 of the PCM connector.
- Circuit K40 connects to cavity A11 of the PCM connector.
- Circuit K59 connects to cavity A20 of the PCM connector.
- Circuit K60 connects to cavity A10 of the PCM connector.