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Home >> Toyota >> 2001 >> Sienna CE >> Repair and Diagnosis >> External Pages >> Different car >> Section 97 (Engine Controls - Self-Diagnostics) >> Diagnostic Tests >> DTC P0505: Idle Control System Malfunction & DTC P0511: Idle Air Control Circuit >> Diagnosis & Repair

Diagnosis & Repair

WARNING: This page is about a different car, the 2003 Lexus RX 300. However, it is still accessible from the selected car via links, so may be relevant.
NOTE: If using OBD-II scan tool, start at step  2.
  1. Warm engine to operating temperature. Turn accessories and A/C off. Place transmission in Neutral. Connect Lexus scan tool to DLC No. 3 and select ACTIVE TEST MODE. See Figure. Using Lexus scan tool, turn TE1 on and off. Record engine speed 5 seconds before and after TE1 is turned on and off. If engine speed changes more than 100 RPM, go to step  9. If engine speed does not change more than 100 RPM, go to step  3.
  2. Warm engine to operating temperature. Turn accessories and A/C off. Place transmission in Neutral. Connect tachometer to DLC No. 3, terminal No. 9 (Orange wire). See Fig 1. Connect Jumper Wire (09843-18020) between DLC No. 3 connector terminals No. 13 (Pink/Black wire) and No. 4 (White/Black wire). DLC No. 1 is located under driver's side of dashboard. Connect and disconnect Jumper Wire (09843-18020) several times. Record engine speed 5 seconds before and after Jumper Wire (09843-18020) is connected and disconnected. If engine speed changes more than 100 RPM, go to step  9. If engine speed does not change more than 100 RPM, go to next step.
    Fig 1: Connecting Tachometer To DLC3
    G00024226Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    Fig 2: Shorting DLC3 Connector Terminals To Check Timing
    G00024227Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  3. Check connection of PCV piping. Repair as necessary. If PCV piping is okay, access ECM behind glove box. Turn ignition off. Disconnect ECM E9 connector. See Figure. Turn ignition on. Using voltmeter, measure voltage between ground and terminal No. 26 (Yellow/Red wire) at ECM E9 connector. If voltage is 9-14 volts, go to step  6. If voltage is not 9-14 volts, go to next step.
  4. Turn ignition off. Disconnect IAC valve harness connector. Measure voltage between ground and terminal No. 2 (Black/Red wire) at IAC valve harness connector. If voltage is 9-14 volts, go to next step. If voltage is not 9-14 volts, repair IAC valve power distribution circuit. See ENGINE PERFORMANCE in WIRING DIAGRAMS article in ELECTRICAL.
  5. Check for open or short in Yellow/Red wire between terminal No. 1 at IAC valve harness connector and terminal No. 26 at ECM harness connector E9. See ENGINE PERFORMANCE in WIRING DIAGRAMS article in ELECTRICAL. If problem exists, repair wiring as necessary. If problem does not exist, replace IAC valve.
  6. Check IAC valve operation. See IDLE AIR CONTROL (IAC) SYSTEM in SYSTEM & COMPONENT TESTING - ES300 & RX300 article. If problem exists, go to next step. If problem does not exist, go to step  8.
  7. Check for open in White/Black wire between ground and terminal No. 3 at IAC valve harness connector. See ENGINE PERFORMANCE in WIRING DIAGRAMS article in ELECTRICAL. If problem exists, repair wiring as necessary. If problem does not exist, replace IAC valve.
  8. Check IAC valve and passages for carbon build-up and blockage. Repair as necessary. If no build-up or blockage exists, replace ECM.
  9. An open or short in A/C switch signal circuit may exist. Check A/C amplifier. See appropriate article in AIR CONDITIONING & HEATING. Repair as necessary.
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