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DTC P0505: Idle Air Control Motor Circuits: Testing

  1. Turn ignition on. Using scan tool, read DTCs. If GOOD TRIP counter is displayed for DTC P0505 and displayed count is "0", go to next step. If GOOD TRIP counter for DTC P0505 is not displayed or displayed count is not "0", go to step  22 .
  2. Start engine and allow it to idle. Disconnect IAC motor connector. Measure voltage between ground and Gray/Red wire at IAC motor harness connector. If voltage changes to more than 5 volts at any time, go to next step. If voltage does not change to more than 5 volts at any time, go to step  19 .
  3. With engine still idling, measure voltage between ground and Yellow/Black wire at IAC motor harness connector. If voltage changes to more than 5 volts at any time, go to next step. If voltage does not change to more than 5 volts at any time, go to step  16 .
  4. With engine still idling, measure voltage between ground and Brown/White wire at IAC motor harness connector. If voltage changes to more than 5 volts at any time, go to next step. If voltage does not change to more than 5 volts at any time, go to step  13 .
  5. With engine still idling, measure voltage between ground and Violet/Black wire at IAC motor harness connector. If voltage changes to more than 5 volts at any time, go to next step. If voltage does not change to more than 5 volts at any time, go to step  10 .
  6. Turn engine off. Ensure IAC motor is still disconnected. Disconnect PCM connectors. PCM is located in engine compartment on left front fender, near radiator support. Inspect connectors for damaged pins, corrosion and loose terminals. Repair connectors as necessary. If connectors are okay, measure resistance between Gray/Red wire and Yellow/Black, Brown/White and Violet/Black wires at IAC motor harness connector. If any resistance reading is less than 5 ohms, Gray/Red wire is shorted to wire with resistance less than 5 ohms. Repair wiring as necessary. If all resistance readings are 5 ohms or more, go to next step.
  7. Measure resistance between Yellow/Black wire and Brown/White and Violet/Black wires at IAC motor harness connector. If any resistance reading is less than 5 ohms, Yellow/Black wire is shorted to wire with resistance less than 5 ohms. Repair wiring as necessary. If all resistance readings are 5 ohms or more, go to next step.
  8. Measure resistance between Brown/White and Violet/Black wires at IAC motor harness connector. If resistance is less than 5 ohms, Brown/White and Violet/Black wires are shorted together. Repair wiring as necessary. If all resistance is 5 ohms or more, go to next step.
  9. At this time, IAC motor is assumed to be defective. Replace IAC motor.
  10. Turn ignition off. Ensure IAC motor is disconnected. Disconnect PCM connectors. Visually inspect connectors for corroded, damaged, pushed-out or miswired terminals. Repair connectors as necessary. If connectors are okay, measure resistance of Violet/Black wire between IAC motor harness connector and terminal No. 20 at PCM C1 harness connector. See Figure . If resistance is 5 ohms or more, repair open in Violet/Black wire. If resistance is less than 5 ohms, go to next step.
  11. Measure resistance between ground and Violet/Black wire at IAC motor harness connector. If resistance is 5 ohms or more, go to next step. If resistance is less than 5 ohms, repair short to ground in Violet/Black wire between IAC motor and PCM.
  12. At this time, PCM is assumed to be defective. Replace PCM.
  13. Turn ignition off. Ensure IAC motor is disconnected. Disconnect PCM connectors. Visually inspect connectors for corroded, damaged, pushed-out or miswired terminals. Repair connectors as necessary. If connectors are okay, measure resistance of Brown/White wire between IAC motor harness connector and terminal No. 11 at PCM C1 harness connector. See Figure . If resistance is 5 ohms or more, repair open in Brown/White wire. If resistance is less than 5 ohms, go to next step.
  14. Measure resistance between ground and Brown/White wire at IAC motor harness connector. If resistance is 5 ohms or more, go to next step. If resistance is less than 5 ohms, repair short to ground in Brown/White wire between IAC motor and PCM.
  15. At this time, PCM is assumed to be defective. Replace PCM.
  16. Turn ignition off. Ensure IAC motor is disconnected. Disconnect PCM connectors. Visually inspect connectors for corroded, damaged, pushed-out or miswired terminals. Repair connectors as necessary. If connectors are okay, measure resistance of Yellow/Black wire between IAC motor harness connector and terminal No. 10 at PCM C1 harness connector. See Figure . If resistance is 5 ohms or more, repair open in Yellow/Black wire. If resistance is less than 5 ohms, go to next step.
  17. Measure resistance between ground and Yellow/Black wire at IAC motor harness connector. If resistance is 5 ohms or more, go to next step. If resistance is less than 5 ohms, repair short to ground in Yellow/Black wire between IAC motor and PCM.
  18. At this time, PCM is assumed to be defective. Replace PCM.
  19. Turn ignition off. Ensure IAC motor is disconnected. Disconnect PCM connectors. Visually inspect connectors for corroded, damaged, pushed-out or miswired terminals. Repair connectors as necessary. If connectors are okay, measure resistance of Gray/Red wire between IAC motor harness connector and terminal No. 19 at PCM C1 harness connector. See Figure . If resistance is 5 ohms or more, repair open in Gray/Red wire. If resistance is less than 5 ohms, go to next step.
  20. Measure resistance between ground and Gray/Red wire at IAC motor harness connector. If resistance is 5 ohms or more, go to next step. If resistance is less than 5 ohms, repair short to ground in Gray/Red wire between IAC motor and PCM.
  21. At this time, PCM is assumed to be defective. Replace PCM.
  22. Start engine and allow it to idle. Using scan tool, go to SYSTEM TESTS and select IAC WIGGLE TEST. While monitoring IAC motor operation, wiggle wiring harness from IAC motor to PCM. PCM is located in engine compartment on left front fender, near radiator support. If IAC motor stops operating at any time while wiggling wiring harness, repair wiring harness where wiggling caused IAC motor to stop operating. If IAC motor does not stop operating at any time while wiggling wiring harness, go to next step.
  23. Visually inspect related connectors and wiring harness for damage. Repair wiring as necessary. If wiring is okay, no problem is indicated at this time. Test is complete.
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