DTC P0506 Idle Air Control System-Rpm Lower Than Expected: General Description

When the TP sensor's signal indicates closed throttle position and the engine is idling, the ECM adjusts the Idle Speed Control Actuator (ISCA) so that the engine runs at the correct idling speed, regardless of coolant temperature, load and etc. When the additional load applied in the engine, the air flow through the idle speed control actuator is increased momentarily to raise the idling speed.