ECD SYSTEM (w/o EGR Cooler), Diagnostic DTC:P0488

DTC Code DTC Name
P0488 Exhaust Gas Recirculation Throttle Position Control Range / Performance

DESCRIPTION

The ECM opens and closes the throttle valve using the rotary solenoid type actuator. The exhaust gas recirculation volume is controlled by opening and closing the valve. Also, engine vibration and noise is reduced by closing the valve when the engine is stopped.

DTC No. DTC Detection Condition Trouble Area
P0488

When either condition below is met:


  • Throttle valve remains closed despite ECM's signal to open valve (1 trip detection logic)

  • Throttle valve remains open despite ECM's signal to close valve (1 trip detection logic)

  • Throttle valve stuck

  • Throttle valve does not move smoothly

  • Open or short in throttle valve circuit

  • Open or short in throttle valve position sensor circuit

  • Throttle position sensor (built in diesel throttle body assembly)

  • ECM

Tech Tips

After confirming DTC P0488, check the throttle position.

Reference
Condition Throttle Valve Position
Moment when accelerator pedal is further depressed or released at 2,500 rpm Opening angle varies smoothly

MONITOR DESCRIPTION

The ECM opens and closes the throttle valve by adjusting the duration of current flowing to the rotary solenoid (duty ratio). If the throttle valve does not move smoothly or is stuck, the duty ratio during the valve movement control increases or decreases greatly, the ECM will determine that the throttle valve has a malfunction and illuminate the MIL.

A01DYDHE12

WIRING DIAGRAM

A01E11ME06

INSPECTION PROCEDURE

Tech Tips


  • Read freeze frame data using the intelligent tester. Freeze frame data records the engine conditions when a malfunction is detected. When troubleshooting, freeze frame data can help determine if the vehicle was running or stopped, if the engine was warmed up or not, and other data from the time the malfunction occurred.

  • After warming up the engine, DTC P0488 is set 1 second or more after quickly accelerating the engine from idling.

Note

If the ECM is replaced, the new ECM needs initialization Click here.

PROCEDURE


  1. CHECK OTHER DTC OUTPUT (IN ADDITION TO DTC P0448)


    1. Connect the intelligent tester to the DLC3.

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

    3. Enter the following menus: Powertrain / Engine / DTC.

    4. Read the DTCs Click here.

      Result
      Display (DTC Output) Proceed to
      P0488 A
      P0488 and P0122 and/or P0123 B

      Tech Tips

      If any other codes besides P0488 are output, perform troubleshooting for those DTCs first.


    B

    GO TO RELEVANT DTC CHART

    A

  2. CHECK IF DTC OUTPUT RECURS (DTC P0448 OUTPUT)


    1. Connect the intelligent tester to the DLC3.

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

    3. Enter the following menus: Powertrain / Engine / DTC / Clear.

    4. Clear the DTCs Click here.

    5. Start the engine and perform a quick engine acceleration from idling to 3,000 rpm 3 times.

    6. Enter the following menus: Powertrain / Engine / DTC.

    7. Read the DTCs Click here.

      Result
      Display (DTC output) Proceed to
      P0488 A
      No output B

      Tech Tips

      The normal operation of the throttle valve is as follows.

      Reference
      Condition Throttle Position
      Moment when accelerator pedal is further depressed or released at 3,000 rpm Opening angle varies smoothly

    B

    CHECK FOR INTERMITTENT PROBLEMS

    A

  3. CHECK ECM (LUSL SIGNAL)

    A01DX7LE02

    1. While revving the engine, check the waveform of the ECM connector using an oscilloscope.

      Standard voltage
      Tester Connection Specified Condition
      E7-4 (LUSL) - E7-7 (E1) Correct waveform is shown
      Tool Setting Condition
      1 V/DIV., 2 msec./DIV. Racing engine with warm engine

      Tech Tips

      The waveform varies depending on the diesel throttle signal operation.


    NG

    REPLACE ECM

    OK

  4. CHECK WIRE HARNESS (THROTTLE CONTROL MOTOR - ECM)

    A01DZSEE02

    1. Disconnect the T1 motor connector.

    2. Disconnect the E7 ECM connector.

    3. Measure the resistance of the wire harness side connectors.

      Standard resistance
      Tester Connection Specified Condition
      T1-1 (DUTY) - E7-4 (LUSL) Below 1 Ω
      T1-1 (DUTY) or E7-4 (LUSL) - Body ground 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS AND CONNECTOR

    OK

    REPLACE DIESEL THROTTLE BODY ASSEMBLY