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DTC P0505: Idle Air Control Motor Circuits

NOTE: For connector terminal ID, see CONNECTOR IDENTIFICATION . For wiring diagram, see WIRING DIAGRAMS article.
NOTE: Idle Air Control (IAC) motor circuits are monitored when ignition is on and battery voltage is more than 11.5 volts. DTC may be stored in Powertrain Control Module (PCM) when PCM senses a short to ground or battery voltage on any of the 4 IAC driver circuits for 2.75 seconds while IAC motor is operating. Possible causes are: defective PCM, defective IAC motor, or defective connectors or wiring.
  1. Connect scan tool to DLC. Monitor Good Trip Counter for P0505. If Good Trip Counter is equal to zero, go to next step. If Good Trip Counter is greater than zero, go to step  60.
  2. Turn ignition off. Disconnect connector at IAC motor. IAC motor is mounted on the throttle body and contains a 4-pin connector. Start engine and allow engine to idle. Using voltmeter, check voltage at IAC motor connector terminal No. 4 (Gray/Red wire). If voltage is more than 5 volts at any time, go to next step. If voltage is not more than 5 volts at any time, go to step  33.
  3. Start engine and allow engine to idle. Using voltmeter, check voltage at IAC motor connector terminal No. 3 (Yellow/Black wire). If voltage is more than 5 volts at any time, go to next step. If voltage is not more than 5 volts at any time, go to step  19.
  4. Start engine and allow engine to idle. Using voltmeter, check voltage at IAC motor connector terminal No. 2 (Brown/White wire). If voltage is more than 5 volts at any time, go to next step. If voltage is not more than 5 volts at any time, go to step  9.
  5. Start engine and allow engine to idle. Using voltmeter, check voltage at IAC motor connector terminal No. 1 (Violet wire). If voltage is more than 5 volts at any time, go to next step. If voltage is not more than 5 volts at any time, go to step  15.
  6. Ensure ignition is off. Disconnect PCM connectors. PCM is located in engine compartment, between air cleaner and radiator. Using ohmmeter, check resistance between IAC motor connector terminal No. 4 (Gray/Red wire) and terminals No. 3 (Yellow/Black wire), No. 2 (Brown/White wire) and No. 1 (Violet wire). If resistance is less than 5 ohms in any measurement, repair appropriate wires that are shorted together. Perform TEST VER-5A . If all resistance measurements are more than 5 ohms, go to next step.
  7. Check resistance between IAC motor connector terminal No. 3 (Yellow/Black wire) and terminals No. 2 (Brown/White wire) and No. 1 (Violet wire). If resistance is less than 5 ohms in any measurement, repair appropriate wires that are shorted together. Perform TEST VER-5A . If all resistance measurements are more than 5 ohms, go to next step.
  8. Check resistance between IAC motor connector terminals No. 2 (Brown/White wire) and No. 1 (Violet wire). If resistance is less than 5 ohms, repair short between Brown/White and Violet wire. Perform TEST VER-5A . If resistance is more than 5 ohms, replace IAC motor. Perform TEST VER-5A .
  9. Start engine and allow engine to idle. Using voltmeter, check voltage at IAC motor connector terminal No. 1 (Violet wire). If voltage is more than 5 volts at any time, go to next step. If voltage is not more than 5 volts at any time, go to step  14.
  10. Turn ignition off. Disconnect PCM connectors. PCM is located in engine compartment, between air cleaner and radiator. Using ohmmeter, check resistance between ground and IAC motor connector terminal No. 2 (Brown/White wire). If resistance is 5 ohms or more, go to next step. If resistance is less than 5 ohms, repair short to ground on Brown/White wire between PCM and IAC motor. Perform TEST VER-5A .
  11. Check resistance between IAC motor connector terminal No. 4 (Gray/Red wire) and terminals No. 3 (Yellow/Black wire), No. 2 (Brown/White wire) and No. 1 (Violet wire). If resistance is less than 5 ohms in any measurement, repair appropriate wires that are shorted together. Perform TEST VER-5A . If all resistance measurements are more than 5 ohms, go to next step.
  12. Check resistance between IAC motor connector terminal No. 3 (Yellow/Black wire) and terminals No. 2 (Brown/White wire) and No. 1 (Violet wire). If resistance is less than 5 ohms in any measurement, repair appropriate wires that are shorted together. Perform TEST VER-5A . If all resistance measurements are more than 5 ohms, go to next step.
  13. Check resistance between IAC motor connector terminals No. 2 (Brown/White wire) and No. 1 (Violet wire). If resistance is less than 5 ohms, repair short between Brown/White and Violet wire. Perform TEST VER-5A . If resistance is more than 5 ohms, replace PCM. Perform TEST VER-5A .
  14. Check resistance between ground and IAC motor connector No. 2 (Brown/White wire). If resistance is less than 5 ohms, repair short to ground on Brown/White wire between PCM and IAC motor. Perform TEST VER-5A . If resistance is 5 ohms or more, go to next step.
  15. Check resistance between ground and IAC motor connector terminal No. 1 (Violet wire). If resistance is 5 ohms or more, go to next step. If resistance is less than 5 ohms, repair short to ground on Violet wire between PCM and IAC motor. Perform TEST VER-5A .
  16. Check resistance between IAC motor connector terminal No. 4 (Gray/Red wire) and terminals No. 3 (Yellow/Black wire), No. 2 (Brown/White wire) and No. 1 (Violet wire). If resistance is less than 5 ohms in any measurement, repair appropriate wires that are shorted together. Perform TEST VER-5A . If all resistance measurements are more than 5 ohms, go to next step.
  17. Check resistance between IAC motor connector terminal No. 3 (Yellow/Black wire) and terminals No. 2 (Brown/White wire) and No. 1 (Violet wire). If resistance is less than 5 ohms in any measurement, repair appropriate wires that are shorted together. Perform TEST VER-5A . If all resistance measurements are more than 5 ohms, go to next step.
  18. Check resistance between IAC motor connector terminals No. 2 (Brown/White wire) and No. 1 (Violet wire). If resistance is less than 5 ohms, repair short between Brown/White and Violet wire. Perform TEST VER-5A . If resistance is more than 5 ohms, replace PCM. Perform TEST VER-5A .
  19. Start engine and allow engine to idle. Using voltmeter, check voltage at IAC motor connector terminal No. 2 (Brown/White wire). If voltage is more than 5 volts at any time, go to next step. If voltage is not more than 5 volts at any time, go to step  27.
  20. Start engine and allow engine to idle. Using voltmeter, check voltage at IAC motor connector terminal No. 1 (Violet wire). If voltage is more than 5 volts at any time, go to next step. If voltage is not more than 5 volts at any time, go to step  22.
  21. Turn ignition off. Ensure connector is still disconnected at IAC motor. Disconnect PCM connectors. PCM is located in engine compartment, between air cleaner and radiator. Using ohmmeter, check resistance between ground and IAC motor connector terminal No. 3 (Yellow/Black wire). If resistance is 5 ohms or more, go to step  24. If resistance is less than 5 ohms, repair short to ground on Yellow/Black wire between PCM and IAC motor. Perform TEST VER-5A .
  22. Turn ignition off. Ensure connector is still disconnected at IAC motor. Disconnect PCM connectors. PCM is located in engine compartment, between air cleaner and radiator. Using ohmmeter, check resistance between ground and IAC motor connector terminal No. 3 (Yellow/Black wire). If resistance is 5 ohms or more, go to next step. If resistance is less than 5 ohms, repair short to ground on Yellow/Black wire between PCM and IAC motor. Perform TEST VER-5A .
  23. Turn ignition off. Ensure connector is still disconnected at IAC motor. Using ohmmeter, check resistance between ground and IAC motor connector terminal No. 1 (Violet wire). If resistance is 5 ohms or more, go to next step. If resistance is less than 5 ohms, repair short to ground on Violet wire between PCM and IAC motor. Perform TEST VER-5A .
  24. Check resistance between IAC motor connector terminal No. 4 (Gray/Red wire) and terminals No. 3 (Yellow/Black wire), No. 2 (Brown/White wire) and No. 1 (Violet wire). If resistance is less than 5 ohms in any measurement, repair appropriate wires that are shorted together. Perform TEST VER-5A . If all resistance measurements are more than 5 ohms, go to next step.
  25. Check resistance between IAC motor connector terminal No. 3 (Yellow/Black wire) and terminals No. 2 (Brown/White wire) and No. 1 (Violet wire). If resistance is less than 5 ohms in any measurement, repair appropriate wires that are shorted together. Perform TEST VER-5A . If all resistance measurements are more than 5 ohms, go to next step.
  26. Check resistance between IAC motor connector terminals No. 2 (Brown/White wire) and No. 1 (Violet wire). If resistance is less than 5 ohms, repair short between Brown/White and Violet wire. Perform TEST VER-5A . If resistance is more than 5 ohms, replace PCM. Perform TEST VER-5A .
  27. Start engine and allow engine to idle. Using voltmeter, check voltage at IAC motor connector terminal No. 1 (Violet wire). If voltage is more than 5 volts at any time, go to next step. If voltage is not more than 5 volts at any time, go to step  32.
  28. Turn ignition off. Ensure connector is still disconnected at IAC motor. Using ohmmeter, check resistance between ground and IAC motor connector terminal No. 3 (Yellow/Black wire). If resistance is 5 ohms or more, go to next step. If resistance is less than 5 ohms, repair short to ground on Yellow/Black wire between PCM and IAC motor. Perform TEST VER-5A .
  29. Turn ignition off. Ensure connector is still disconnected at IAC motor. Using ohmmeter, check resistance between ground and IAC motor connector terminal No. 1 (Brown/White wire). If resistance is 5 ohms or more, go to next step. If resistance is less than 5 ohms, repair short to ground on Brown/White wire between PCM and IAC motor. Perform TEST VER-5A .
  30. Check resistance between IAC motor connector terminal No. 4 (Gray/Red wire) and terminals No. 3 (Yellow/Black wire), No. 2 (Brown/White wire) and No. 1 (Violet wire). If resistance is less than 5 ohms in any measurement, repair appropriate wires that are shorted together. Perform TEST VER-5A . If all resistance measurements are more than 5 ohms, go to next step.
  31. Check resistance between IAC motor connector terminal No. 3 (Yellow/Black wire) and terminals No. 2 (Brown/White wire) and No. 1 (Violet wire). If resistance is less than 5 ohms in any measurement, repair appropriate wires that are shorted together. Perform TEST VER-5A . If all resistance measurements are more than 5 ohms, replace PCM. Perform TEST VER-5A .
  32. Check resistance between IAC motor connector terminals No. 2 (Brown/White wire) and No. 1 (Violet wire). If resistance is less than 5 ohms, repair short between Brown/White and Violet wire. Perform TEST VER-5A . If resistance is more than 5 ohms, go to step  58.
  33. Start engine and allow engine to idle. Using voltmeter, check voltage at IAC motor connector terminal No. 3 (Yellow/Black wire). If voltage is more than 5 volts at any time, go to next step. If voltage is not more than 5 volts at any time, go to step  45.
  34. Start engine and allow engine to idle. Using voltmeter, check voltage at IAC motor connector terminal No. 2 (Brown/White wire). If voltage is more than 5 volts at any time, go to next step. If voltage is not more than 5 volts at any time, go to step  41.
  35. Start engine and allow engine to idle. Using voltmeter, check voltage at IAC motor connector terminal No. 1 (Violet wire). If voltage is more than 5 volts at any time, go to next step. If voltage is not more than 5 volts at any time, go to step  37.
  36. Turn ignition off. Ensure connector is still disconnected at IAC motor. Disconnect PCM connectors. PCM is located in engine compartment, between air cleaner and radiator. Using ohmmeter, check resistance between ground and IAC motor connector terminal No. 4 (Gray/Red wire). If resistance is 5 ohms or more, go to step  39. If resistance is less than 5 ohms, repair short to ground on Gray/Red wire between PCM and IAC motor. Perform TEST VER-5A .
  37. Turn ignition off. Ensure connector is still disconnected at IAC motor. Disconnect PCM connectors. PCM is located in engine compartment, between air cleaner and radiator. Using ohmmeter, check resistance between ground and IAC motor connector terminal No. 4 (Gray/Red wire). If resistance is 5 ohms or more, go to next step. If resistance is less than 5 ohms, repair short to ground on Gray/Red wire between PCM and IAC motor. Perform TEST VER-5A .
  38. Check resistance between ground and IAC motor connector terminal No. 1 (Violet wire). If resistance is 5 ohms or more, go to next step. If resistance is less than 5 ohms, repair short to ground on Violet wire between PCM and IAC motor. Perform TEST VER-5A .
  39. Check resistance between IAC motor connector terminal No. 4 (Gray/Red wire) and terminals No. 3 (Yellow/Black wire), No. 2 (Brown/White wire) and No. 1 (Violet wire). If resistance is less than 5 ohms in any measurement, repair appropriate wires that are shorted together. Perform TEST VER-5A . If all resistance measurements are more than 5 ohms, go to next step.
  40. Check resistance between IAC motor connector terminal No. 3 (Yellow/Black wire) and terminals No. 2 (Brown/White wire) and No. 1 (Violet wire). If resistance is less than 5 ohms in any measurement, repair appropriate wires that are shorted together. Perform TEST VER-5A . If all resistance measurements are more than 5 ohms, replace PCM. Perform TEST VER-5A .
  41. Start engine and allow engine to idle. Using voltmeter, check voltage at IAC motor connector terminal No. 1 (Violet wire). If voltage is more than 5 volts at any time, go to next step. If voltage is not more than 5 volts at any time, go to step  57.
  42. Turn ignition off. Ensure connector is still disconnected at IAC motor. Disconnect PCM connectors. PCM is located in engine compartment, between air cleaner and radiator. Using ohmmeter, check resistance between ground and IAC motor connector terminal No. 4 (Gray/Red wire). If resistance is 5 ohms or more, go to next step. If resistance is less than 5 ohms, repair short to ground on Gray/Red wire between PCM and IAC motor. Perform TEST VER-5A .
  43. Check resistance between ground and IAC motor connector terminal No. 2 (Brown/White wire). If resistance is 5 ohms or more, go to next step. If resistance is less than 5 ohms, repair short to ground on Brown/White wire between PCM and IAC motor. Perform TEST VER-5A .
  44. Check resistance between IAC motor connector terminal No. 4 (Gray/Red wire) and terminals No. 3 (Yellow/Black wire), No. 2 (Brown/White wire) and No. 1 (Violet wire). If resistance is less than 5 ohms in any measurement, repair appropriate wires that are shorted together. Perform TEST VER-5A . If all resistance measurements are more than 5 ohms, replace PCM. Perform TEST VER-5A .
  45. Start engine and allow engine to idle. Using voltmeter, check voltage at IAC motor connector terminal No. 2 (Brown/White wire). If voltage is more than 5 volts at any time, go to next step. If voltage is not more than 5 volts at any time, go to step  52.
  46. Check voltage at IAC motor connector terminal No. 1 (Violet wire). If voltage is more than 5 volts at any time, go to next step. If voltage is not more than 5 volts at any time, go to step  49.
  47. Turn ignition off. Ensure connector is still disconnected at IAC motor. Disconnect PCM connectors. PCM is located in engine compartment, between air cleaner and radiator. Using ohmmeter, check resistance between ground and IAC motor connector terminal No. 3 (Yellow/Black wire). If resistance is 5 ohms or more, go to next step. If resistance is less than 5 ohms, repair short to ground on Yellow/Black wire between PCM and IAC motor. Perform TEST VER-5A .
  48. Check resistance between ground and IAC motor connector terminal No. 4 (Gray/Red wire). If resistance is 5 ohms or more, replace PCM. Perform TEST VER-5A . If resistance is less than 5 ohms, repair short to ground on Gray/Red wire between PCM and IAC motor. Perform TEST VER-5A .
  49. Turn ignition off. Ensure connector is still disconnected at IAC motor. Disconnect PCM connectors. PCM is located in engine compartment, between air cleaner and radiator. Using ohmmeter, check resistance between ground and IAC motor connector terminal No. 3 (Yellow/Black wire). If resistance is 5 ohms or more, go to next step. If resistance is less than 5 ohms, repair short to ground on Yellow/Black wire between PCM and IAC motor. Perform TEST VER-5A .
  50. Check resistance between ground and IAC motor connector terminal No. 4 (Gray/Red wire). If resistance is 5 ohms or more, go to next step. If resistance is less than 5 ohms, repair short to ground on Gray/Red wire between PCM and IAC motor. Perform TEST VER-5A .
  51. Check resistance between ground and IAC motor connector terminal No. 1 (Violet wire). If resistance is 5 ohms or more, go to step  59. If resistance is less than 5 ohms, repair short to ground on Violet wire between PCM and IAC motor. Perform TEST VER-5A .
  52. Ensure engine is still idling. Check voltage at IAC motor connector terminal No. 1 (Violet wire). If voltage is more than 5 volts at any time, go to next step. If voltage is not more than 5 volts at any time, go to step  56.
  53. Turn ignition off. Ensure connector is still disconnected at IAC motor. Disconnect PCM connectors. PCM is located in engine compartment, between air cleaner and radiator. Using ohmmeter, check resistance between ground and IAC motor connector terminal No. 3 (Yellow/Black wire). If resistance is 5 ohms or more, go to next step. If resistance is less than 5 ohms, repair short to ground on Yellow/Black wire between PCM and IAC motor. Perform TEST VER-5A .
  54. Check resistance between ground and IAC motor connector terminal No. 4 (Gray/Red wire). If resistance is 5 ohms or more, go to next step. If resistance is less than 5 ohms, repair short to ground on Gray/Red wire between PCM and IAC motor. Perform TEST VER-5A .
  55. Check resistance between ground and IAC motor connector terminal No. 1 (Brown/White wire). If resistance is 5 ohms or more, replace PCM. Perform TEST VER-5A . If resistance is less than 5 ohms, repair short to ground on Brown/White wire between PCM and IAC motor. Perform TEST VER-5A .
  56. Turn ignition off. Ensure connector is still disconnected at IAC motor. Disconnect PCM connectors. PCM is located in engine compartment, between air cleaner and radiator. Using ohmmeter, check resistance between ground and IAC motor connector terminal No. 3 (Yellow/Black wire). If resistance is 5 ohms or more, go to next step. If resistance is less than 5 ohms, repair short to ground on Yellow/Black wire between PCM and IAC motor. Perform TEST VER-5A .
  57. Check resistance between ground and IAC motor connector terminal No. 4 (Gray/Red wire). If resistance is 5 ohms or more, go to next step. If resistance is less than 5 ohms, repair short to ground on Gray/Red wire between PCM and IAC motor. Perform TEST VER-5A .
  58. Check resistance between ground and IAC motor connector terminal No. 1 (Violet wire). If resistance is 5 ohms or more, go to next step. If resistance is less than 5 ohms, repair short to ground on Violet wire between PCM and IAC motor. Perform TEST VER-5A .
  59. Check resistance between ground and IAC motor connector terminal No. 1 (Brown/White wire). If resistance is 5 ohms or more, replace PCM. Perform TEST VER-5A . If resistance is less than 5 ohms, repair short to ground on Brown/White wire between PCM and IAC motor. Perform TEST VER-5A .
  60. Inspect PCM and IAC motor connectors for corroded, pushed out, miswired or damaged terminals. If terminals are not corroded, pushed out, miswired or damaged, go to next step. If terminals are corroded, pushed out, miswired or damaged, repair connectors as necessary. Perform TEST VER-5A .
  61. Allow engine to idle. Using scan tool in SYSTEM TESTS, perform IAC WIGGLE test. Idle speed should increase and then decrease in accordance with display on scan tool if IAC motor is operating correctly. If IAC motor operates correctly, test is complete. If IAC motor does not operate correctly, repair harness or connectors as necessary. Perform TEST VER-5A .
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