DTC P0506: Description
WARNING: This page is about a different car, the 2007 Saturn Vue. However, it is still accessible from the selected car via links, so may be relevant.
The DTC P0506 Idle Speed Low diagnostic monitors the engine speed. The powertrain control module (PCM) controls the throttle actuator control (TAC) motor in order to regulate the air flow through the throttle body. The amount of air flowing through the throttle body determines the engine speed. If there is a malfunction in the TAC system or other engine control system, DTC P0506 can set.