ECD SYSTEM(for CCo), 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 a DC motor type actuator. Due to the opening and closing of the valve, the exhaust gas recirculation volume can be properly controlled. Also, engine vibration and noise will be reduced by closing the valve when the engine is stopped.

Although the DTC title says "Exhaust Gas Recirculation Throttle Position Control Range / Performance", this DTC indicates that the throttle valve is malfunctioning.

DTC No.

Detection Item

DTC Detection Condition

Trouble Area

MIL

Memory

P0488

Exhaust Gas Recirculation Throttle Position Control Range / Performance

The throttle motor activation duty is more than specified value for 30 seconds (1 trip detection logic).

  • Throttle valve stuck

  • Throttle valve does not move smoothly

  • Open or short in throttle control motor circuit

  • ECM

Comes on

DTC stored
Table 1. Related Data List

DTC No.

Data List

P0488

  • Actual Throttle Position

  • Target Throttle Position

  • Throttle Motor Duty

  • Throttle Close Learning Val.

  • Diesel Throttle Learn Status
Table 2. Reference

Condition

Throttle Valve Position

Moment when accelerator pedal is depressed further or released at 3000 rpm

Throttle valve opening angle varies smoothly

MONITOR DESCRIPTION

The ECM opens and closes the throttle valve by adjusting the current flowing to the DC motor with a duty ratio. If the throttle valve does not move smoothly or is stuck, the duty ratio used during valve movement control increases or decreases greatly. The ECM will determine that the throttle valve is malfunctioning and illuminate the MIL.

Table 3. Normal Condition

Throttle Condition

Target Throttle Position

Actual Throttle Position

Throttle Close Learning Val.

Diesel Throttle Learn Status

Throttle Valve Fully Closed

100%

100%

14.25 to 21.25 deg

OK

Throttle Valve Fully Open

0%

0%
A206049E01
Tip:

If carbon deposits exist in the diesel throttle body assembly, the following parts possibly also have deposits inside: The electric EGR control valve assembly, intake manifold and other parts related to the exhaust gas.

By removing the electric EGR control valve assembly from the intake manifold, the carbon deposit condition between the EGR valve and intake manifold can be checked visually. When checking for deposits in the electric EGR control valve assembly, hold the EGR valve to a light and confirm that the valve contacts the valve seat securely.

A204075C01

*1

Electric EGR Control Valve Assembly

*2

No. 2 EGR Pipe

CONFIRMATION DRIVING PATTERN

DTC No.

DTC Detection Drive Pattern

P0488

Perform the following repeatedly for 1 minute: gradually raise the engine speed to 3000 rpm from an idling over approximately 10 seconds, and then release the accelerator pedal to return to an idling state.

WIRING DIAGRAM

A206856E08

CAUTION / NOTICE / HINT

Note:

  • When cleaning the EGR valve or diesel throttle body, use a piece of cloth soaked with cleaning solvent. Spraying the solvent directly onto these parts or soaking the parts in solvent may damage the parts.

  • After replacing the ECM, the new ECM needs registration (Click here) and initialization (Click here).

PROCEDURE

  1. CHECK ANY OTHER DTCS OUTPUT (IN ADDITION TO DTC P0488)

    1. Connect the GTS to the DLC3.

    2. Turn the ignition switch to ON and turn the GTS on.

    3. Enter the following menus: Powertrain / Engine and ECT / Trouble Codes.

      Powertrain > Engine > Trouble Codes

    4. Read the DTCs.

      Result

      Proceed to

      DTC P0488 is output

      DTC P0488 and other DTCs are output
      Tip:

      • If any DTCs other than DTC P0488 are output, troubleshoot those DTCs first.

      • Be sure to also record the values of "Actual Throttle Position" and "Target Throttle Position" listed in the freeze frame data.

    DTC P0488 and other DTCs are output

    GO TO DTC CHART

    Click hereClick here

    DTC P0488 is output

  2. READ VALUE USING GTS (DIESEL THROTTLE LEARN STATUS)

    1. Connect the GTS to the DLC3.

    2. Turn the ignition switch to ON and turn the GTS on.

    3. Clear the DTCs.

      Powertrain > Engine > Clear DTCs

    4. Turn the ignition switch off for 30 seconds or more.

      Tip:

      Be sure to turn off the ignition switch before performing this inspection. The fully closed position of the diesel throttle valve is learned when the ignition switch is turned off.

    5. Enter the following menus: Powertrain / Engine and ECT / Data List / Diesel Throttle Learn Status.

      Powertrain > Engine > Data List

      Tester Display

      Diesel Throttle Learn Status

    6. Read the values when the ignition switch is ON.

      Standard

      Diesel Throttle Learn Status is OK

      Note:

      Extremely cold conditions might cause the throttle valve movement to be delayed.

    Result

    Proceed to

    OK

    NG
    NG

    REMOVE DEPOSIT (CLEAN EGR PASSAGE)Click here

    OK

  3. PERFORM ACTIVE TEST USING GTS (DIESEL THROTTLE TARGET ANGLE)

    1. Connect the GTS to the DLC3.

    2. Turn the ignition switch to ON and turn the GTS on.

    3. Enter the following menus: Powertrain / Engine and ECT / Active Test / Diesel Throttle Target Angle.

      Powertrain > Engine > Active Test

      Tester Display

      Diesel Throttle Target Angle

    4. When changing the Active Test continuously value to 0, 30, 60, 90, 60, 30 and 0%, check that Actual Throttle Position smoothly changes to the set opening angle.

      OK

      Value smoothly changes to set opening angle.

    Result

    Proceed to

    OK

    NG
    NG

    REMOVE DEPOSIT (CLEAN EGR PASSAGE)Click here

    OK

  4. REMOVE DEPOSIT (CLEAN EGR PASSAGE)

    1. Remove the electric EGR control valve assembly, No. 2 intake manifold and intake manifold.

    2. Remove the deposits from those parts and clean the parts.

      A204074C03

      *1

      No. 2 Intake Manifold

      *2

      Electric EGR Control Valve Assembly

      *3

      Intake Manifold

      -

      -

      *a

      Carbon Deposit

      -

      -
      Note:

      • When cleaning the EGR valve and diesel throttle body, use a piece of cloth soaked with cleaning solvent. Spraying the solvent directly onto these parts or soaking the parts in solvent may damage the parts.

      • Extreme care must be taken to prevent the removed deposits from falling into the engine unit during cleaning.

      Tip:

      Remove the intake manifold from the cylinder head when it has to be cleaned.

    Result

    Proceed to

    NEXT
    NEXT

  5. INSPECT DIESEL THROTTLE BODY ASSEMBLY (THROTTLE VALVE MOVEMENT)

    1. Using your finger, move the throttle valve from the fully open position to the fully closed position and check that it moves smoothly.

      OK

      Throttle valve moves smoothly.

      Note:

      Take care not to damage the throttle valve or valve housing.

    Result

    Proceed to

    OK

    NG
    OK

    CHECK WHETHER DTC OUTPUT RECURS (DTC P0488)Click here

    NG

  6. REPLACE DIESEL THROTTLE BODY ASSEMBLY

    1. Replace the diesel throttle body assembly.

      Click here

    Result

    Proceed to

    NEXT
    NEXT

  7. CHECK WHETHER DTC OUTPUT RECURS (DTC P0488)

    1. Start the engine and warm it up.

    2. Connect the GTS to the DLC3.

    3. Turn the GTS on.

    4. Enter the following menus: Powertrain / Engine and ECT / Data List / Engine Speed, Target Throttle Position and Actual Throttle Position.

      Powertrain > Engine > Data List

      Tester Display

      Engine Speed

      Target Throttle Position

      Actual Throttle Position

    5. Take a snapshot with the GTS.

    6. Enter the following menus: Powertrain / Engine and ECT / Active Test / Diesel Throttle Target Angle.

      Powertrain > Engine > Active Test

      Tester Display

      Diesel Throttle Target Angle
      Tip:

      The movement of the throttle valve can be determined by performing the following inspection.

    7. When changing the Active Test value continuously to 0, 30, 60, 90, 60, 30 and 0%, check that Actual Throttle Position smoothly changes to the set opening angle.

      OK

      Value smoothly changes to set opening angle.

    8. Perform the following repeatedly for 1 minute: gradually raise the engine speed to 3000 rpm from an idling over approximately 10 seconds, and then release the accelerator pedal to return to an idling state.

    9. Enter the following menus: Powertrain / Engine and ECT / Trouble Codes.

      Powertrain > Engine > Trouble Codes

    10. Read the DTCs.

      OK

      DTC is not output.

    Result

    Proceed to

    OK

    NG
    OK

    END

    NG

    REPLACE ECMClick here

  8. REMOVE DEPOSIT (CLEAN EGR PASSAGE)

    1. Remove the EGR valve assembly, No. 2 intake manifold and intake manifold.

    2. Remove the deposits from those parts and clean the parts.

      A204074C03

      *1

      No. 2 Intake Manifold

      *2

      Electric EGR Control Valve Assembly

      *3

      Intake Manifold

      -

      -

      *a

      Carbon Deposit

      -

      -
      Note:

      • When cleaning the EGR valve and diesel throttle body, use a piece of cloth soaked with cleaning solvent. Spraying the solvent directly onto these parts or soaking the parts in solvent may damage the parts.

      • Extreme care must be taken to prevent the removed deposits from falling into the engine unit during cleaning.

      Tip:

      Remove the intake manifold from the cylinder head when it has to be cleaned.

    3. Reinstall the EGR valve assembly, No. 2 intake manifold and intake manifold.

    Result

    Proceed to

    NEXT
    NEXT

  9. INSPECT DIESEL THROTTLE BODY ASSEMBLY (THROTTLE VALVE MOVEMENT)

    1. Using your finger, move the throttle valve from the fully open position to the fully closed position and check that it moves smoothly.

      OK

      Throttle valve moves smoothly.

      Note:

      Take care not to damage the throttle valve or valve housing.

    Result

    Proceed to

    OK

    NG
    NG

    REPLACE DIESEL THROTTLE BODY ASSEMBLYClick here

    OK

  10. CHECK HARNESS AND CONNECTOR (ECM - DIESEL THROTTLE BODY ASSEMBLY)

    1. Disconnect the diesel throttle body assembly connector.

    2. Disconnect the ECM connector.

    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection

      Condition

      Specified Condition

      B3-5 (VC) - B76-97 (VCVL)

      Always

      Below 1 Ω

      B3-6 (VTA) - B76-119 (VLU)

      Always

      Below 1 Ω

      B3-3 (E2) - B76-96 (EVLU)

      Always

      Below 1 Ω

      B3-2 (M+) - B76-42 (M+)

      Always

      Below 1 Ω

      B3-1 (M-) - B76-43 (M-)

      Always

      Below 1 Ω

      B3-5 (VC) or B76-97 (VCVL) - Body ground

      Always

      10 kΩ or higher

      B3-6 (VTA) or B76-119 (VLU) - Body ground

      Always

      10 kΩ or higher

      B3-3 (E2) or B76-96 (EVLU) - Body ground

      Always

      10 kΩ or higher

      B3-2 (M+) or B76-42 (M+) - Body ground

      Always

      10 kΩ or higher

      B3-1 (M-) or B76-43 (M-) - Body ground

      Always

      10 kΩ or higher

    Result

    Proceed to

    OK

    NG
    OK

    REPLACE DIESEL THROTTLE BODY ASSEMBLYClick here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTORClick here

  11. REPLACE ECM

    1. Replace the ECM.

      Click here

    Result

    Proceed to

    NEXT
    NEXT

  12. CHECK WHETHER DTC OUTPUT RECURS (DTC P0488)

    1. Start the engine and warm it up.

    2. Connect the GTS to the DLC3.

    3. Turn the GTS on.

    4. Enter the following menus: Powertrain / Engine and ECT / Data List / Engine Speed, Target Throttle Position and Actual Throttle Position.

      Powertrain > Engine > Data List

      Tester Display

      Engine Speed

      Target Throttle Position

      Actual Throttle Position

    5. Take a snapshot with the GTS.

    6. Enter the following menus: Powertrain / Engine and ECT / Active Test / Diesel Throttle Target Angle.

      Powertrain > Engine > Active Test

      Tester Display

      Diesel Throttle Target Angle
      Tip:

      The movement of the throttle valve can be determined by performing the following inspection.

    7. When changing the Active Test value continuously to 0, 30, 60, 90, 60, 30 and 0%, check that Actual Throttle Position smoothly changes to the set opening angle.

      OK

      Value smoothly changes to set opening angle.

    8. Perform the following repeatedly for 1 minute: gradually raise the engine speed to 3000 rpm from an idling over approximately 10 seconds, and then release the accelerator pedal to return to an idling state.

    9. Enter the following menus: Powertrain / Engine and ECT / Trouble Codes.

      Powertrain > Engine > Trouble Codes

    10. Confirm that the DTC is not output again.

    Result

    Proceed to

    NEXT
    NEXT

    END

  13. REPAIR OR REPLACE HARNESS OR CONNECTOR

    1. Repair or replace the harness or connector.

    Result

    Proceed to

    NEXT
    NEXT

    CHECK WHETHER DTC OUTPUT RECURS (DTC P0488)Click here