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DTC P0506: Idle Control System RPM Lower Than Expected

NOTE: Before you troubleshoot, record all freeze data and any on-board snapshot, and review GENERAL TROUBLESHOOTING INFORMATION .
  1. Turn the ignition switch ON (II).
  2. Clear the DTC with the HDS.
  3. Start the engine. Hold the engine speed at 3,000 RPM without load (in neutral) until the radiator fan comes on, then let it idle.
  4. Check this data in the DATA LIST with the HDS.
    • ECT SENSOR above 158°F (70°C)
    • IAT SENSOR above 32°F (0°C)
    • VSS is 0 mph (0 km/h)
    • ST FUEL TRIM between 0.73 and 1.47
    • FSS is CLOSED
  5. Monitor the OBD STATUS for DTC P0506 in the DTCs MENU with the HDS.

    Does the screen indicate FAILED? 

    1. YES  - Go to step  6.
    2. NO  - If the screen indicates PASSED, go to step  15. If the screen indicates EXECUTING, let the engine idle until a result comes on. If the screen indicates OUT OF CONDITION, go to step  4 and recheck.
  6. Remove the intake air duct from the throttle body.
  7. Check for dirt, carbon, or damage in the throttle bore.

    Is there dirt, carbon, or damage in the throttle bore? 

    1. YES  - If there is dirt or carbon, clean the throttle body (see THROTTLE BODY CLEANING ). Also check for damage at the air cleaner element (see AIR CLEANER REMOVAL/INSTALLATION ), then go to step  9. If there is damage in the throttle bore, go to step  8.
    2. NO  - Check the A/C system or power steering system, then go to step  17.
  8. Replace the throttle body (see THROTTLE BODY REMOVAL/INSTALLATION ).
  9. Reset the ECM with the HDS.
  10. Do ECM IDLE LEARN PROCEDURE  .
  11. Start the engine. Hold the engine speed at 3,000 RPM without load (in neutral) until the radiator fan comes on, then let it idle.
  12. Check this data in the DATA LIST with the HDS.
    • ECT SENSOR above 158°F (70°C)
    • IAT SENSOR above 32°F (0°C)
    • VSS is 0 mph (0 km/h)
    • ST FUEL TRIM between 0.73 and 1.47
    • FSS is CLOSED
  13. Check for Temporary DTCs or DTCs with the HDS.

    Are any Temporary DTCs or DTCs indicated? 

    1. YES  - If DTC P0506 is indicated, go to step  1 and recheck. If any other temporary DTCs or DTCs are indicated, go to the indicated DTCs troubleshooting.
    2. NO  - Go to step  14.
  14. Monitor the OBD STATUS for DTC P0506 in the DTCs MENU with the HDS.

    Does the screen indicate PASSED? 

    1. YES  - Troubleshooting is complete.
    2. NO  - If the screen indicates FAILED, go to step  1 and recheck. If the screen indicates EXECUTING, let the engine idle until a result comes on. If the screen indicates OUT OF CONDITION, go to step  12 and recheck.
  15. Remove the intake air duct from the throttle body.
  16. Check for dirt, carbon, or damage in the throttle bore.

    Is there dirt, carbon, or damage in the throttle bore? 

    1. YES  - If there is dirt or carbon, clean the throttle body (see THROTTLE BODY CLEANING ). Also check for damage at the air cleaner element (see AIR CLEANER REMOVAL/INSTALLATION ), then go to step  9. If there is damage in the throttle bore, go to step  8.
    2. NO  - Go to step  17.
  17. Recheck with different load conditions (turn on the headlights, blower motor, rear window defogger and/or A/C, changing the gear position, etc.)
  18. Monitor the OBD STATUS for DTC P0506 in the DTCs MENU with the HDS.

    Does the screen indicate PASSED? 

    1. YES  - Intermittent failure, system is OK at this time.
    2. NO  - If the screen indicates FAILED, check the A/C system and/or power steering system, then go to step  1 and recheck. If the screen indicates EXECUTING, let the engine idle until a result comes on. If the screen indicates OUT OF CONDITION, go to step  17 and recheck.
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