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Home >> Toyota >> 2003 >> Matrix Base, FWD, Automatic >> Repair and Diagnosis >> External Pages >> Different car >> Section 17 (Engine Control System Self-Diagnostics - V6) >> Diagnostic Tests >> DTC P0505: Idle Control System Malfunction >> Diagnosis & Repair
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Diagnosis & Repair

WARNING: This page is about a different car, the 2002 Toyota Tundra. However, it is still accessible from the selected car via links, so may be relevant.
  1. Start engine and warm to engine to normal operating temperature. Ensure A/C and all accessories are off. Apply parking brake. Place transmission in Neutral. Install jumper wire (SST 09843-18020 or SST 09843-18040) between TC and CG terminals on Data Link Connector (DLC) No. 3. See Fig 1. Note engine speed in less than 5 seconds and at more than 5 seconds after installing jumper wire. If difference in engine speed is 100 RPM or less, go to next step. If difference in engine speed is more than 100 RPM, go to step  7.
    Fig 1: Installing Jumper Wire Between Data Link Connector No. 3 Terminals
    G00032701Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  2. Turn ignition off. Check for any loose or defective PCV valve hose connections. PCV valve is located on top of passenger's side valve cover near front corner of valve cover. If PCV valve hose connections are okay, go to next step. If PCV valve hose connections are defective, repair or replace components as necessary.
  3. Remove glove box and heater duct (if necessary) for access to ECM with electrical connectors still installed on ECM. See Figure. Disconnect ECM electrical connector E7. See Figure.
  4. Turn ignition on. Using voltmeter, check voltage between body ground and terminals No. 15 (Black/Red wire) and No. 16 (Red/White wire) at ECM electrical connector E7. See Figure. This is the RSC and RSO terminals on ECM. Voltage should be 9-14 volts. If voltage is within specification, go to next step. If voltage is not within specification, check IAC valve operation. See IDLE AIR CONTROL VALVE under IDLE CONTROL SYSTEMS in SYSTEM & COMPONENT TESTING - V6 & V8 article. If IAC valve is defective, replace IAC valve. If IAC valve is okay, check for open and short in wiring harness and electrical connectors between IAC valve and ECM, and between IAC valve and EFI main relay. See WIRING DIAGRAMS article. EFI main relay may also be referred to as EFI relay. EFI main relay is located in fuse/relay box at driver's side front corner of engine compartment. Repair wiring as necessary.
  5. Check IAC valve operation. See IDLE AIR CONTROL VALVE under IDLE CONTROL SYSTEMS in SYSTEM & COMPONENT TESTING - V6 & V8 article. If IAC valve is okay, go to next step. If IAC valve is defective, replace IAC valve.
  6. Remove IAC valve from throttle body. Inspect IAC valve and passages for carbon build-up and blockage. If a problem exist, repair as necessary. If problem does not exist, replace ECM.
  7. Ensure engine 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 problem does not exist, an open and short in A/C signal circuit may exist. Check A/C control assembly which may also be referred to as center cluster integration. See MANUAL A/C-HEATER SYSTEMS article in AIR CONDITIONING & HEATING. Repair as necessary.
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