Fuel System > Engine Control System > P0506 Idle Air Control System-RPM Lower than Expected

General Description

The idle speed is controlled by the Electrical Throttle Control(ETC) System. ETC system is composed of the throttle motor to operate the throttle valve and the throttle position sensor to detect the opening angle of the throttle valve, the accelerator pedal position sensor to detect the accelerator pedal position and the one valve type throttle body. The PCM controls the throttle motor to provide the proper throttle valve opening angle for the target idle speed.

DTC Description

Checking idle RPM under detecting condition, if if the real idle speed is lower than desired idle speed by 100 RPM over 10 sec., PCM sets P0506. MIL(Malfunction Indication Lamp) turns on when the malfunction lasts till consecutive 2 driving cycle.

DTC Detecting Condition

Item

Detecting Condition

Possible cause

DTC Strategy

•	Monitor idle speed

•	Intake system for blockage

Enable Conditions

•	Normal idle conditions

Thresh old value

•	Real engine speed is lower than target engine speed by 100 RPM

Diagnosis Time

•	Continuous

MIL On Condition

•	2 driving cycles

Monitor Scantool Data

1.	Monitor DTCs related to HO2S, MAFS, MAPS, ECTS, PCSV, Injector, CVVT items, ETC system, A/C system, or power steering system with scantool.

Are related DTCs present?

	▶ Do all repairs associated with those codes before proceeding with this procedure.
	▶ Go to "System Inspection" procedure

System Inspection

Check intake/exhaust system for blockage

(1)	Visually/physically inspect the following items: - Air cleaner filter element for excessive dirt or for any foreign objects - Hoses of intake system for blockage - Throttle body inlet for damage or for any foreign objects - Throttle plate for carbon deposits

(2)

Has a problem been found in any of the above areas?

	▶ Repair it and go to "Verification of Vehicle Repair" procedure
	▶ Clear DTC and Test-drive under enable conditions above-mentioned. After the test, If this DTC is set, go to "Inspection amp;amp; Repair" procedure. If not, troubleshooting is completed.

Verification Of Vehicle Repair

After a repair, it is essential to verify that the fault has been corrected.

1.	Connect scantool and select "DTC" button.

2.	Press "DTC Status" button and confirm that "DTC Readiness Flag" indicates "Completed". If not, drive the vehicle within conditions noted in the freeze frame data or enable conditions

3.	Read "DTC Status" parameter

Is parameter displayed "History(Not Present) fault"?

	▶ System performing to specification at this time. Clear the DTC
	▶ Go to the applicable troubleshooting procedure.