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DTC P0505 Idle Control System Malfunction: Description

WARNING: This page is about a different car, the 2007 Lexus SC 430. However, it is still accessible from the selected car via links, so may be relevant.

The idle speed is controlled by the Electronic Throttle Control System (ETCS). The ETCS is comprised of: 1) one valve type throttle body; 2) the throttle actuator, which operates the throttle valve; 3) the throttle position sensor, which detects the opening angle of the throttle valve; 4) the accelerator pedal position sensor, which detects the accelerator pedal position; and 5) the ECM, which controls the ETCS. Based on the target idle speed, the ECM controls the throttle actuator to provide the proper throttle valve opening angle.

DTC DETECTION CONDITION CHART

DTC No. DTC Detection Condition Trouble Area
P0505 Idle speed continues to vary greatly from target speed (2 trip detection logic)
  • ETCS
  • Air induction system
  • PCV hose connection
  • ECM