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Home >> Toyota >> 2004 >> Matrix Base, FWD, Automatic >> Repair and Diagnosis >> External Pages >> Different car >> Section 33 (Engine Controls - Self-Diagnostics) >> Diagnostic Tests >> DTC P0505: Idle Air Control System Circuit >> Diagnosis & Repair
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Diagnosis & Repair

WARNING: This page is about a different car, the 2002 Lexus ES 300. However, it is still accessible from the selected car via links, so may be relevant.
  1. Check for other DTCs and diagnose those DTCs first. If no other DTCs are present, go to next step.
  2. Check air induction system. Ensure oil dipstick, oil filler cap, PCV system and all other air induction system components are intact and operating properly. If problem exists, repair as necessary. If not problem is present, go to next step.
  3. Inspect throttle body and throttle control motor. See THROTTLE CONTROLS in SYSTEM & COMPONENT TESTING - ES300 & RX300 article. Check accelerator pedal position sensor. Connect hand-held tester to DLC No. 3. See Figure. Check that check engine warning light does not illuminate. When turning accelerator pedal position sensor lever to full-open position, check that throttle valve opening percentage (THROTTLE POS) of CURRENT DATA shows standard value of 60 percent or more. If standard value is not to specification, replace throttle body assembly. If standard valve is to specification, go to next step.
  4. Check throttle body assembly harness and connectors. See WIRING DIAGRAMS article. If harness and connectors are okay, go to next step.
  5. Check throttle position sensor. See THROTTLE CONTROLS in SYSTEM & COMPONENT TESTING - ES300 & RX300 article. If throttle position sensor is okay, go to next step.
  6. Check throttle position sensor to ECM harness and connectors. See WIRING DIAGRAMS article. Repair as necessary. If harness and connectors are okay, replace ECM.
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