СИСТЕМА ECD, 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 to 21.25 deg OK
Throttle Valve Fully Open 0% 0%
A012JE1E05
Tip:
  • If carbon deposits exist in the diesel throttle body assembly, the following parts may also have deposits inside: electric EGR control valve assembly, intake manifold, exhaust fuel addition injector, DPF catalyst, 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 electric EGR control valve assembly 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.

    A012MH9C01
    *1 Electric EGR Control Valve Assembly *2 No. 2 EGR Pipe
  • DPF catalyst diagnosis:

    The value of "Catalyst Differential Press" in the Data List is high when the catalyst is clogged. If this value exceeds approximately 0.4, DTC P244B is stored.

    If the "Catalyst Differential Press" become near about 0.4, the catalyst is probably clogged with PM even if DTC P244B is not present.

    Check the Catalyst Differential Press when the engine is running at 3000 rpm with no load. Enter the following menus: Powertrain / Engine and ECT / Data List / All Data / Catalyst Differential Press.

    If the value of MAF in the Data List is less than 25 gm/sec, a correct value for Catalyst Differential Press is not output due to exhaust gas pulsation.

  • Exhaust fuel addition injector assembly diagnosis:

    When the fuel volume injected by the exhaust fuel addition injector assembly decreases, the value of "Exhaust Fuel Addition FB" in the Data List increases. Exhaust Fuel Addition FB in the Data List is a correction value to increase the fuel volume injected from the exhaust fuel addition injector assembly when the catalyst temperature does not rise to the target during catalyst regeneration. Under normal conditions, the value is between 0.9 and 1.45.

    Check the value by entering the following menus on an GTS: Powertrain / Engine and ECT / Data List / All Data / Exhaust Fuel Addition FB. Under normal conditions, the exhaust gas temperature becomes 150 to 350°C (302 to 662°F) when the vehicle is driven in 3rd gear at a constant vehicle speed of about 50 km/h (31 mph). While driving under these conditions, the exhaust gas temperature rises to 500 to 700°C (932 to 1292°F) when the catalyst regeneration function in the Active Test (Activate the DPF Rejuvenate (PM)) is performed. If the temperature does not rise sufficiently, the exhaust fuel addition injector assembly or the DPF catalyst may be damaged.

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

A012FAAE01
Table 4.
*a Magnet
*b Hall IC
*c Shielded
*d Diesel Throttle Body Assembly

CAUTION / NOTICE / HINT

Note:
  • When cleaning the electric EGR control valve assembly or diesel throttle body assembly, use a piece of cloth soaked with cleaning solvent. Spraying 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 hereНажмите здесь).

Tip:

Read freeze frame data using the GTS. Freeze frame data records the engine condition 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, and other data from the time the malfunction occurred.

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.

    4. Read the DTCs.

      Powertrain > Engine and ECT > Trouble Codes
      Result
      ResultProceed to
      DTC P0488 is outputA
      DTC P0488 and other DTCs are outputB
      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.

    B

    GO TO GO TO DTC CHART Click here Нажмите здесь


    A
  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 and ECT > 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. Turn the ignition switch to ON and turn the GTS on.

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

      Powertrain > Engine and ECT > Data List
      Tester Display
      Diesel Throttle Learn Status
    7. 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 Нажмите здесь

    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 / All Data / Actual Throttle Position.

      Powertrain > Engine and ECT > Active Test
      Active Test Display
      Diesel Throttle Target Angle
      Data List Display
      Actual Throttle Position
    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 Нажмите здесь

    GO TO STEP 8


    OK
  4. REMOVE DEPOSIT (CLEAN EGR PASSAGE)

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

      Click hereНажмите здесь

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

      A012JYWC01
      *1 No. 2 Intake Manifold *2 Electric EGR Control Valve Assembly
      *3 Intake Manifold - -
      *a Carbon Deposit - -
      Note:
      • When cleaning the electric EGR control valve assembly and diesel throttle body assembly, use a piece of cloth soaked with cleaning solvent. Spraying 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 Нажмите здесь

    GO TO STEP 7


    NG
  6. REPLACE DIESEL THROTTLE BODY ASSEMBLY

    1. Replace the diesel throttle body assembly.

      Click hereНажмите здесь

      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 / All Data / Engine Speed, Target Throttle Position and Actual Throttle Position.

      Powertrain > Engine and ECT > 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 / All Data / Actual Throttle Position.

      Powertrain > Engine and ECT > Active Test
      Active Test Display
      Diesel Throttle Target Angle
      Data List Display
      Actual Throttle Position
      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.

    10. Read the DTCs.

      Powertrain > Engine and ECT > Trouble Codes
      OK
      DTC is not output.
      Result
      Proceed to
      OK
      NG
    OK

    END


    NG Нажмите здесь

  8. REMOVE DEPOSIT (CLEAN EGR PASSAGE)

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

      Click hereНажмите здесь

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

      A012JYWC01
      *1 No. 2 Intake Manifold *2 Electric EGR Control Valve Assembly
      *3 Intake Manifold - -
      *a Carbon Deposit - -
      Note:
      • When cleaning the electric EGR control valve assembly and diesel throttle body assembly, use a piece of cloth soaked with cleaning solvent. Spraying 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
  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 Нажмите здесь

    GO TO STEP 6


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

    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
      B25-5 (VC) - B164-97 (VCVL) Always Below 1 Ω
      B25-6 (VTA) - B164-119 (VLU) Always Below 1 Ω
      B25-3 (E2) - B164-96 (EVLU) Always Below 1 Ω
      B25-2 (M+) - B164-42 (M+) Always Below 1 Ω
      B25-1 (M-) - B164-43 (M-) Always Below 1 Ω
      B25-5 (VC) or B164-97 (VCVL) - Body ground Always 10 kΩ or higher
      B25-6 (VTA) or B164-119 (VLU) - Body ground Always 10 kΩ or higher
      B25-2 (M+) or B164-42 (M+) - Body ground Always 10 kΩ or higher
      B25-1 (M-) or B164-43 (M-) - Body ground Always 10 kΩ or higher
      Result
      Proceed to
      OK
      NG
    OK Нажмите здесь

    GO TO STEP 6


    NG Нажмите здесь

  11. REPLACE ECM

    1. Replace the ECM.

      Click hereНажмите здесь

      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 / All Data / Engine Speed, Target Throttle Position and Actual Throttle Position.

      Powertrain > Engine and ECT > 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 / All Data / Actual Throttle Position.

      Powertrain > Engine and ECT > Active Test
      Active Test Display
      Diesel Throttle Target Angle
      Data List Display
      Actual Throttle Position
      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.

    10. Confirm that the DTC is not output.

      Powertrain > Engine and ECT > Trouble Codes
      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 Нажмите здесь

    GO TO STEP 12