DTC Troubleshooting

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.

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 Park or neutral) until the radiator fan comes on, then let it idle.
4. Check for these conditions in the DATA LIST with the HDS:
- ECT SENSOR 1 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?

YES - Go to step 6.

NO - If the screen indicates PASSED, Go to step 8. 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?

YES - If there is dirt or carbon, clean the throttle body. Also check for damage to the air cleaner element, then Go to step 13. If there is damage in the throttle bore, Go to step 12.

NO - Check the NC system or power steering system, then Go to step 10.

8. Remove the intake air duct from the throttle body.
9. 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, Also check for damage to the air cleaner element, then Go to step 13. If there is damage in the throttle bore, Go to step 12.

NO - Go to step 10.

10. Recheck with different load conditions (turn on the headlights, blower motor, or NC; change the gear position, etc.).
11. 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 NC 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 10 and recheck.

12. Replace the throttle body.
13. Reset the PCM with the HDS.
14. Do the PCM idle learn procedure.
15. Start the engine. Hold the engine speed at 3,000 rpm without load (in Park or neutral) until the radiator fan comes on, then let it idle.
16. Check for these conditions in the DATA LIST with the HDS:
- ECT SENSOR 1 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

17. 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 PCM. If the PCM was updated, substitute a known good PCM, then recheck. If the PCM was substituted, Go to step 1.

NO-Go to step 18.

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

Does the screen indicate PASSED?

YES - If the PCM was updated, troubleshooting is complete. If the PCM was substituted, replace the original PCM. If any other Temporary DTCs or DTCs were indicated in step 17, 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 PCM. If the PCM was updated, substitute a known good PCM, then recheck. If the PCM was substituted, Go to step 1. If the screen indicates EXECUTING or OUT OF CONDITION, keep idling until a result comes on.