DTC Troubleshooting

Control System DTCs

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 How To Troubleshoot The Fuel And Emissions Systems.

1. Problem verification:

Problem verification
-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 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)
* VEHICLE SPEED is 0 mph (0 km/h)
* ST FUEL TRIM between 0.69 and 1.47
* FSS is CLOSED

-5. Monitor the OBD STATUS for DTC P0506 in the DTCs MENU with the HDS.

Does the HDS indicate FAILED?
-YES- The failure is duplicated. Go to step 2.
-NO- If the HDS indicates PASSED, go to step 3. If the HDS indicates EXECUTING, keep idling until a result comes on. If the HDS indicates OUT OF CONDITION, go to step 1-4 and recheck.

2. Throttle body visual check:

Throttle body visual check
-1. Remove the intake air duct from the throttle body. Removal and Replacement

-2. 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 Throttle Body Cleaning. Also check for damage to the air cleaner element, then do the repair verification. If there is damage in the throttle bore, replace the throttle body Removal and Replacement, then do the repair verification.
-NO- The throttle body is OK. Check the A/C system, then go to step 4.

3. Throttle body visual check:

Throttle body visual check
-1. Remove the intake air duct from the throttle body. Removal and Replacement

-2. 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 Throttle Body Cleaning. Also check for damage to the air cleaner element, then do the repair verification. If there is damage in the throttle bore, replace the throttle body Removal and Replacement, then do the repair verification.
-NO- The throttle body is OK. Go to step 4.

4. Idle control system check:

Idle control system check
-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 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)
* VEHICLE SPEED is 0 mph (0 km/h)
* ST FUEL TRIM between 0.69 and 1.47
* FSS is CLOSED

NOTE: Recheck with different load conditions (turn on the headlights, the blower motor, the rear window defogger, and/or the A/C, change the gear position, etc.).

-5. Monitor the OBD STATUS for DTC P0506 in the DTCs MENU with the HDS.

Does the HDS indicate PASSED?
-YES- Intermittent failure, the system is OK at this time.
-NO- If the HDS indicates FAILED, check the A/C system, then go to step 1 and recheck. If the HDS indicates EXECUTING, keep idling until a result comes on. If the HDS indicates OUT OF CONDITION, go to step 4-4.

Repair verification (OBD STATUS check):

-1. Turn the ignition switch to LOCK (0).

-2. Reconnect all connectors.

-3. Turn the ignition switch to ON (II).

-4. Reset the ECM with the HDS How To Troubleshoot The Fuel And Emissions Systems.

-5. Do the ECM idle learn procedure ECM/PCM Idle Learn Procedure.

-6. 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.

-7. 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)
* VEHICLE SPEED is 0 mph (0 km/h)
* ST FUEL TRIM between 0.69 and 1.47
* FSS is CLOSED

-8. Monitor the OBD STATUS for DTC P0506 in the DTCs MENU with the HDS.

Does the HDS indicate PASSED, FAILED, EXECUTING, or OUT OF CONDITION?
-PASSED- Troubleshooting is complete. If any other Pending or Confirmed DTCs were indicated, go to the indicated DTC's troubleshooting.
-FAILED- Go to step 1 and recheck.
-EXECUTING- Keep idling until a result comes on.
-OUT OF CONDITION- Meet the test condition, and check the OBD STATUS again.