SFI SYSTEM, Diagnostic DTC:P0505

DTC Code DTC Name
P0505 Idle Control System Malfunction

DESCRIPTION

The idle speed is controlled by the Electronic Throttle Control System (ETCS).

The ETCS is composed of the throttle actuator which operates the throttle valve, and the throttle position sensor which detects an opening angle of the throttle valve.

The ECM controls the throttle motor to provide the proper throttle valve opening angle to obtain the target idling speed.

DTC No. DTC Detection Condition Trouble Area
P0505 Idling speed continues to vary greatly from target speed (2 trip detection logic)

  • ETCS

  • Air induction system

  • PCV hose connection

MONITOR DESCRIPTION

The ECM regulates the idle speed by opening and closing the throttle valve using the ETCS. The ECM concludes that the idle speed control function is malfunctioning if: 1) the actual idle rpm varies more than the specified amount 5 times or more during a drive cycle, or 2) a learned value of the idle speed control remains at the maximum or minimum 5 times or more during a drive cycle. The ECM will turn on the MIL and set a DTC.

Example:

If the actual idle rpm varies from the target idle rpm by more than 200* rpm 5 times during a drive cycle, the ECM will turn on the MIL and the DTC is set.

Tech Tips

*: The rpm threshold varies with engine load.

A01DXR1E08

INSPECTION PROCEDURE

Tech Tips

Read freeze frame data using the intelligent tester. Freeze frame data records the engine conditions when malfunctions are detected. When troubleshooting, freeze frame data can help determine if the vehicle was moving or stationary, if the engine was warmed up or not, if the air-fuel ratio was lean or rich, and other data from the time the malfunction occurred.

PROCEDURE


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


    1. Connect the intelligent tester to the DLC3.

    2. Turn the ignition switch ON and turn the intelligent tester ON.

    3. Select the following the menu items: Powertrain / Engine and ECT / DTC.

    4. Read DTCs.

      Result
      Display (DTC output) Proceed to
      P0505 A
      P0505 and other DTCs B

      Tech Tips

      If any other DTCs besides P0505 are output, perform troubleshooting for those DTCs first.


    B

    GO TO RELEVANT DTC CHART

    A

  2. CHECK PCV HOSE

    OK
    The PCV hose is connected correctly, and the PCV hose has no damage.

    NG

    RECONNECT OR REPLACE PCV HOSE

    OK

  3. CHECK AIR INDUCTION SYSTEM


    1. Check for vacuum leaks in the air induction system.

      OK
      No leak in the air induction system.

    NG

    REPAIR OR REPLACE AIR INDUCTION SYSTEM

    OK

  4. CHECK THROTTLE VALVE


    1. Check the throttle valve condition.


    NG

    REPLACE THROTTLE BODY ASSEMBLY

    OK

    REPLACE ECM