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DTC P0505 Idle Control System Malfunction

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DESCRIPTION

The idle speed is controlled by the electronic throttle control system. The electronic throttle control system is comprised of: 1) the one valve type throttle body; 2) a throttle actuator, which operates the throttle valve; 3) a throttle position sensor, which detects the opening angle of the throttle valve; 4) an accelerator pedal position sensor, which detects the accelerator pedal position; and 5) the ECM, which controls the electronic throttle control system. Based on the target idle speed, the ECM controls the throttle actuator to provide the proper throttle valve opening angle.

DTC No.	DTC Detection Condition	Trouble Area
P0505	Idling speed continues to vary greatly from target idling speed (2 trip detection logic)	Electronic throttle control system Intake system PCV hose connections EGR valve assembly ECM

INSPECTION PROCEDURE

HINT:

The following conditions may also cause DTC P0505 to be set:

The floor carpet overlapping slightly onto the accelerator pedal, causing the accelerator pedal to be slightly depressed and therefore the throttle valve position to be slightly open.
The accelerator pedal being not fully released.

Read freeze frame data using the intelligent tester. The ECM records vehicle and driving condition information as freeze frame data the moment a DTC is stored. When troubleshooting, freeze frame data can be helpful in determining whether the vehicle was running or stopped, whether the engine was warmed up or not, whether the air fuel ratio was lean or rich, as well as other data recorded at the time of a malfunction.

1.CHECK ANY OTHER DTCS OUTPUT (IN ADDITION TO DTC P0505)

Connect the intelligent tester to the DLC3.

Turn the power switch on (IG).

Turn the tester on.

Enter the following menus: Powertrain / Engine and ECT / DTC.

Read the DTCs.
Result:
Result
Proceed to
DTC P0505 is output
A
DTC P0505 and other DTCs are output
B
HINT:
If any DTCs other than P0505 are output, troubleshoot those DTCs first.

GO TO DTC CHART (Click here)

A

2.CHECK PCV HOSE CONNECTIONS

Check the PCV hose connections (Click here).

OK:: PCV hose is connected correctly and is not damaged.

REPAIR OR REPLACE PCV HOSE

OK

3.CHECK INTAKE SYSTEM

Check the intake system for vacuum leaks (Click here).
OK:
No leaks from the intake system.

REPAIR OR REPLACE INTAKE SYSTEM

OK

4.INSPECT THROTTLE BODY ASSEMBLY (VISUALLY CHECK THROTTLE VALVE)

Check for contamination between the throttle valve and the housing and then check that the throttle valve moves smoothly.
OK:
Throttle valve is not contaminated with foreign objects and moves smoothly.

REPLACE THROTTLE BODY ASSEMBLY (Click here)

OK

5.PERFORM ACTIVE TEST USING INTELLIGENT TESTER (CONTROL THE EGR STEP POSITION)

Connect the intelligent tester to the DLC3.

Turn the power switch on (IG).

Turn the tester on.

Put the engine in inspection mode (Click here).

Start the engine and warm it up until the engine coolant temperature reaches 75°C (167°F) or more.
HINT:
The A/C switch and all accessory switches should be off.

Enter the following menus: Powertrain / Engine and ECT / Active Test / Control the EGR Step Position.

Confirm the Throttle Idle Position is ON and check the engine idling condition and MAP values in the Data List while performing the Active Test.

HINT:

Do not leave the EGR valve open for 10 seconds or more during the Active Test.
Be sure to return the EGR valve to step 0 when the Active Test is completed.
Do not open the EGR valve 30 steps or more during the Active Test.

OK:: MAP and idling condition change in response to EGR step position when Throttle Idle Position is ON in Data List.

Standard:

-	EGR Step Position (Active Test)
-	0 Steps	0 to 30 Steps
Idling condition	Steady idling	Idling changes from steady to rough idling
MAP (Data List)	MAP value is 20 to 40 kPa (150 to 300 mmHg) (EGR valve is fully closed)	MAP value is at least +10 kPa (75 mmHg) higher than when EGR valve is fully closed

HINT:

During Active Test, if the idling condition does not change in response to EGR step position, then there is probably a malfunction in the EGR valve.

Result:

Result	Proceed to
Outside of standard range	A
Within standard range	B

Go to step 7

A

6.INSPECT EGR VALVE ASSEMBLY

Remove the EGR valve assembly (Click here).

Check if the EGR valve is stuck open.
OK:
EGR valve is tightly closed.

Reinstall the EGR valve assembly (Click here).

REPLACE EGR VALVE ASSEMBLY (Click here)

OK

7.REPLACE ECM

Replace the ECM (Click here).

NEXT

8.CONFIRM WHETHER MALFUNCTION HAS BEEN SUCCESSFULLY REPAIRED

Connect the intelligent tester to the DLC3.

Turn the power switch on (IG).

Turn the tester on.

Enter the following menus: Powertrain / Engine and ECT / Data List / Coolant Temp.

Make sure that the coolant temperature is 60°C (140°F) or less.
HINT:
If the coolant temperature is 60°C (140°F) or more, the engine may stop when idling. Make sure to keep the coolant temperature at 60°C (140°F) or less during the driving pattern.

Clear the DTC (Click here).

Turn the power switch off and wait for 30 seconds..

Turn the power switch on (IG) and turn the tester on.

Put the engine in inspection mode (Click here).

Start the engine and drive the vehicle until the coolant temperature reaches 70°C (158°F).

Stop the vehicle (0 km/h (0 mph)).

Accelerate the vehicle to 55 to 60 km/h (34 to 37 mph) or more, and then idle the engine [A].
HINT:
If the vehicle speed reaches more than 60 km/h (37 mph), the engine may stop while decelerating.

Stop the vehicle (0 km/h (0 mph)) [B].

Repeat steps [A] and [B] for 5 times or more.

Enter the following menus: Powertrain / Engine and ECT / Utility / All Readiness.

Input the DTC: P0505.

Check the DTC judgment result.

END

Result	Proceed to
DTC P0505 is output	A
DTC P0505 and other DTCs are output	B