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Home >> Lexus >> 2002 >> SC 430 >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Self-Diagnostics >> Diagnostic Tests >> DTC P0505: Idle Control System Malfunction >> Diagnosis & Repair
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Diagnosis & Repair

  1. Retrieve trouble codes. See RETRIEVING DIAGNOSTIC TROUBLE CODES  under SELF-DIAGNOSTIC SYSTEM. If only DTC P0505 is displayed, go to next step. If other codes are displayed, diagnose and repair those codes first and retest.
  2. Check for loose, damaged or cracked air intake hose between throttle body and air cleaner. Check for loose or damaged dipstick, oil fill cap or PCV hose. Repair as necessary. If all components are okay, go to next step.
  3. Check throttle control system. When turning accelerator pedal position sensor lever, check throttle control motor for operating sound. Ensure there is no friction sound. Connect scan tool to DLC No. 3. See Figure. Ensure check engine light does not come on. When turning accelerator pedal position sensor lever to full-open position, ensure throttle valve opening percentage of CURRENT DATA shows standard value of 60 percent or more. See THROTTLE CONTROLS in SYSTEM & COMPONENT TESTING - GS300, IS300, GS430, LS430 & SC430 article. Repair as necessary. If throttle controls are okay, go to next step.
  4. Check wire harness between ECM and throttle body. See WIRING DIAGRAMS article.
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