Circuit Description
WARNING: This page is about a different car, the 2002 Isuzu Trooper. However, it is still accessible from the selected car via links, so may be relevant.
Powertrain Control Module (PCM) controls engine speed by adjusting position of throttle control valve. Throttle control valve is a DC motor driven by one coil. PCM applies current to DC motor coil changing idle speed. If PCM detects an idle speed below specification, and PCM is unable to adjust idle speed by increasing the throttle position, DTC P0506 will set, indicating a idle control system concern.
When DTC sets, PCM illuminates MIL on second trip after fault was detected. PCM will store conditions present when DTC was set as freeze frame data in the FAILURE RECORDS data.
DTC can be cleared with scan tool, or by disconnecting battery voltage feed to PCM.