DTC Troubleshooting

DTC Troubleshooting: P0506

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. Initial Inspection and Diagnostic Overview

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 neutral) until the radiator fan comes on, then let it idle.

4. Check under these DATA LIST conditions 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 0.69-1.47

- 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, go to step 4 and recheck.


6. Remove the intake air duct from the throttle body. Removal and Replacement

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. Procedures Also check for damage to the air cleaner element, Testing and Inspection then go to step 9. If there is damage in the throttle bore, go to step 8.

NO - Check the A/C system or the EPS system, then go to step 9.


8. Replace the throttle body. Removal and Replacement

9. Reset the ECM with the HDS.

10. Do the ECM idle learn procedure. 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 under these DATA LIST conditions 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 0.69-1.47

- FSS is CLOSED

13. Check for Temporary DTCs or DTCs with the HDS.

Is DTC P0506 indicated?
YES - Go to step 19.

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 Temporary DTCs or DTCs were indicated in step 13, go to the indicated DTC's troubleshooting.

NO - If the screen indicates FAILED, go to step 19. If the screen indicates EXECUTING, keep idling until a result comes on. If the screen indicates OUT OF CONDITION, go to step 11.


15. Remove the intake air duct from the throttle body. Removal and Replacement

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. Procedures Also check for damage to the air cleaner element, Testing and Inspection 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 the EPS 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 17.


19. Update the ECM if it does not have the latest software, ECM Update or substitute a known-good ECM. Initial Inspection and Diagnostic Overview

20. 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.

21. Check under these DATA LIST conditions 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 0.69-1.47

- FSS is CLOSED

22. Check for Temporary DTCs or DTCs with the HDS.

Is DTC P0506 indicated?
YES - Check for poor connections or loose terminals at the throttle body and the ECM. If the ECM was updated, substitute a known-good ECM, Initial Inspection and Diagnostic Overview then go to step 20. If the ECM was substituted, go to step 1.

NO - Go to step 23.


23. Monitor the OBD STATUS for DTC P0506 in the DTCs MENU with the HDS.

Does the screen indicate PASSED?
YES - If the ECM was updated, troubleshooting is complete. If the ECM was substituted, replace the original ECM. Service and Repair If any other Temporary DTCs or DTCs were indicated in step 22, go to the indicated DTC's troubleshooting.

NO - If the screen indicates FAILED, check for poor connections or loose terminals at the throttle body and the ECM. If the ECM was updated, substitute a known-good ECM, Initial Inspection and Diagnostic Overview then go to step 20. If the ECM was substituted, go to step 1. If the screen indicates EXECUTING, keep idling until a result comes on. If the screen indicates OUT OF CONDITION, go to step 20.