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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 the general troubleshooting information (see GENERAL TROUBLESHOOTING INFORMATION ).
  1. Turn the ignition switch to ON (II).
  2. Clear the DTC with the HDS.
  3. Start the engine. Hold the engine speed at 3,000 rpm without load (in P or N) until the radiator fan comes on, then let it idle.
  4. Check under these DATA LIST parameters with the HDS:
    • ECT SENSOR 1 above 156 °F (70 °C)
    • IAT SENSOR above 32 °F (0 °C)
    • VSS is 0 mph (0 km/h)
    • ST FUEL TRIM between 0.75-1.47
    • FSS is CLOSED
  5. Monitor the OBD STATUS for DTC P0506 in the DTCs MENU with the HDS.

    Does the screen indicate FAILED? 

    YES  -Go to step 6.

    NO  -If the screen indicates PASSED, go to step  15. If the screen indicates EXECUTING, keep idling until a result comes on. If the screen indicates OUT OF CONDITION or NOT COMPLETED, go to step  4 and recheck.

  6. Remove the air cleaner (see AIR CLEANER REMOVAL/INSTALLATION ).
  7. Check for dirt, carbon, or damage in the throttle bore.

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

    YES  -If there is dirt or carbon, clean the throttle body (see THROTTLE BODY CLEANING ). Also check for damage to 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.

    NO  -Check the A/C system and the power steering system, then go to step  17.

  8. Replace the throttle body (see THROTTLE BODY REMOVAL/INSTALLATION ).
  9. Reset the PCM with the HDS.
  10. Do the PCM idle learn procedure (see PCM IDLE LEARN PROCEDURE  ).
  11. Start the engine. Hold the engine speed at 3,000 rpm without load (in P or N) until the radiator fan comes on, then let it idle.
  12. Check under these DATA LIST parameters with the HDS:
    • ECT SENSOR 1 above 156 °F (70 °C)
    • AT SENSOR above 32 °F (0 °C)
    • VSS is 0 mph (0 km/h)
    • ST FUEL TRIM between 0.75-1.47
    • FSS is CLOSED
  13. Check for Pending or Confirmed DTCs or DTCs with the HDS.

    Is DTC P0506 indicated? 

    YES  -Check the A/C system and/or the power steering system, then go to step  1.

    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? 

    YES  -Troubleshooting is complete. If any other Pending or Confirmed DTCs were indicated in step 13, go to the indicated DTC's troubleshooting.

    NO  -If the HDS indicates FAILED, check the A/C system and/or the power steering system, then go to step  1. If the HDS indicates EXECUTING, keep idling until a result comes on. If the HDS indicates OUT OF CONDITION, go to step  11.

  15. Remove the air cleaner (see AIR CLEANER REMOVAL/INSTALLATION ).
  16. Check for dirt, carbon, or damage in the throttle bore.

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

    YES  -If there is dirt or carbon, clean the throttle body (see THROTTLE BODY CLEANING ). Also check for damage to 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.

    NO  -Go to step 17.

  17. Recheck with different load conditions (turn on the headlights, blower motor, rear window defogger and/or A/C, change the gear position, etc.).
  18. Monitor the OBD STATUS for DTC P0506 in the DTCs MENU with the HDS.

    Does the screen indicate PASSED? 

    YES  -Intermittent failure, the system is OK at this time.

    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, keep idling until a result comes on. If the screen indicates OUT OF CONDITION, go to step  11.