ECD SYSTEM, 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. With the throttle 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.

Tech Tips

Although the DTC titles say Exhaust Gas Recirculation Throttle Position Control Range / Performance, these DTCs relate to the throttle valve.

P0488
DTC Detection Drive Pattern DTC Detection Condition Trouble Area
With a warm engine, turn the ignition switch from ON to off and wait for one minute or more to perform the close learning operation.

Either of following conditions is met:

(1 trip detection logic)


  • DC motor duty is higher than specified value for 0.5 seconds for predetermined number of times

  • The target and actual positions of the throttle valve are different for 20 seconds

  • Throttle valve stuck

  • Throttle valve does not move smoothly

  • Open or short in diesel throttle circuit

  • ECM
Related Data List
DTC No. Data List
P0488

  • Target Throttle Position

  • Actual Throttle Position

  • Throttle Motor DUTY
Reference
Condition Throttle Valve Position
Moment when accelerator pedal is depressed further or released between idling and 3000 rpm Throttle valve opening angle varies smoothly

Tech Tips


  • If DTC P0488 is stored, the following symptoms may appear:


    • Poor acceleration

    • Lack of power due to a fail-safe operation

    • Combustion noise worsens

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

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

A005JTUE04
Text in Illustration
*1 EGR Pipe Connector *2 Electric EGR Valve Assembly
*3 Intake Air Connector *4 EGR No. 2 Valve Assembly
*5 EGR w/Cooler Pipe Assembly - -

Tech Tips

If the DPF catalyst has become clogged with PM (Particulate Matter) and the value of the "PM Accumulation Ratio" is more than 135% at an engine speed of 4000 rpm, DTC P2463 (Diesel Particulate Filter Restriction - Soot Accumulation) may be present. If the value of the "PM Accumulation Ratio" is about 135% or less at an engine speed of 4000 rpm, the catalyst is probably clogged with PM even if DTC P2463 is not present. Check the PM Accumulation Ratio by entering the following menus on an intelligent tester: Powertrain / Engine and ECT / Data List / PM Accumulation Ratio.

MONITOR DESCRIPTION


WIRING DIAGRAM

Refer to DTC P0122 Click here.

CAUTION / NOTICE / HINT

Note


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

  • When replacing the ECM, the ECM needs Registration and Initialization Click here.

Tech Tips


  • When the ECM must be replaced, before replacing the ECM, perform the "Learning Values Save" function using the intelligent tester. Then after installing the new ECM, perform all of the initializations/registrations for the "Learning Values Write" function by following the instructions shown on the tester display.

  • Read freeze frame data using the intelligent tester. 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 intelligent tester to the DLC3.

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

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

    4. Read the DTCs.

      Result
      Result Proceed to
      DTC P0488 A
      DTC P0488 and P2100, P2101, P2102 and/or P2103 B

      Tech Tips

      If any DTC P2100, P2101, P2102 and/or P2103 other than DTC P0488 are output, troubleshoot those DTCs first.


    B

    GO TO DTC CHART Click here

    A

  2. PERFORM ACTIVE TEST USING INTELLIGENT TESTER (DIESEL THROTTLE TARGET ANGLE)


    1. Connect the intelligent tester to the DLC3.

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

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

    4. When continuously changing the Active Test 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 the set opening angle.

    NG

    CHECK FOR DEPOSIT (DIESEL THROTTLE BODY ASSEMBLY) Click here

    OK

  3. INSPECT VACUUM HOSE AND PIPE (BETWEEN INTERCOOLER AND INTAKE MANIFOLD)


    1. Check for water or water marks in the hoses and pipes between the intercooler and intake manifold.

      OK
      No water or water marks in the hoses and pipes.

      Tech Tips

      If water or water marks exist, water may have frozen in the diesel throttle body. The DTC was possibly caused by the presence of ice.

    2. Inspect the hoses and pipes between the intercooler and intake manifold.

      OK
      Hoses and pipes are not damaged, squashed, or disconnected.

    OK

    CHECK FOR DEPOSIT (DIESEL THROTTLE BODY ASSEMBLY) Click here

    NG

  4. REPAIR OR REPLACE VACUUM HOSE AND PIPE


    1. Repair or replace the vacuum hoses or pipes.


    NEXT

  5. CHECK FOR DEPOSIT (DIESEL THROTTLE BODY ASSEMBLY)


    1. Check for any deposits in the diesel throttle body assembly.

      OK
      No deposits in the diesel throttle body assembly.

      Tech Tips

      If carbon deposits exist in the diesel throttle body assembly, the following parts possibly also have deposits inside: the EGR valve assembly, intake manifold, DPF catalyst, and other parts related to the exhaust gas. By removing the EGR 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 EGR valve assembly, hold the EGR valve to a light and confirm that the valve contacts with the valve seat securely.

    2. If there are deposits, remove the deposits from those parts and clean them.

      Note

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

      A005I8TE03
      Text in Illustration
      *1 Electric EGR Valve Assembly *2 Diesel Throttle Body Assembly
      *3 Intake Air Connector - -

    NEXT

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


    1. Using your finger, check that the throttle valve moves smoothly.

      OK
      Throttle valve moves smoothly.

      Note

      Take care that you do not damage the throttle valve and the valve housing.


    OK

    CHECK WHETHER DTC OUTPUT RECURS Click here

    NG

    REPLACE DIESEL THROTTLE BODY ASSEMBLY Click here

  7. CHECK FOR DEPOSIT (DIESEL THROTTLE BODY ASSEMBLY)


    1. Check for any deposits in the diesel throttle body assembly.

      OK
      No deposits in the diesel throttle body assembly.

      Tech Tips

      If carbon deposits exist in the diesel throttle body assembly, the following parts possibly also have deposits inside: the EGR valve assembly, intake manifold, DPF catalyst, and other parts related to the exhaust gas. By removing the EGR 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 EGR valve assembly, hold the EGR valve to a light and confirm that the valve contacts with the valve seat securely.

    2. If there are deposits, remove the deposits from those parts and clean them.

      Note

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

      A005I8TE03
      Text in Illustration
      *1 Electric EGR Valve Assembly *2 Diesel Throttle Body Assembly
      *3 Intake Air Connector - -

    NEXT

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


    1. Using your finger, check that the throttle valve moves smoothly.

      OK
      Throttle valve moves smoothly.

      Note

      Take care that you do not damage the throttle valve and the valve housing.


    NG

    REPLACE DIESEL THROTTLE BODY ASSEMBLY Click here

    OK

  9. CHECK HARNESS AND CONNECTOR (DIESEL THROTTLE BODY - 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 (Check for Open)
      Tester Connection Condition Specified Condition
      B81-2 (M+) - A59-43 (M+) Always Below 1 Ω
      B81-1 (M-) - A59-42 (M-) Always Below 1 Ω
      Standard Resistance (Check for Short)
      Tester Connection Condition Specified Condition
      B81-2 (M+) or A59-43 (M+) - Body ground Always 10 kΩ or higher
      B81-1 (M-) or A59-42 (M-) - Body ground Always 10 kΩ or higher

    4. Reconnect the diesel throttle body assembly connector.

    5. Reconnect the ECM connector.


    OK

    REPLACE DIESEL THROTTLE BODY ASSEMBLY Click here

    NG

  10. REPAIR OR REPLACE HARNESS OR CONNECTOR


    NEXT

    CHECK WHETHER DTC OUTPUT RECURS Click here

  11. REPLACE DIESEL THROTTLE BODY ASSEMBLY


    1. Replace the diesel throttle body assembly Click here.


    NEXT

  12. CHECK WHETHER DTC OUTPUT RECURS


    1. Connect the intelligent tester to the DLC3.

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

    3. Clear DTCs Click here.

    4. Turn the ignition switch off and wait for 1 minute or more.

    5. Turn the ignition switch to ON.

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

    7. Read the DTCs.

      Result
      Result Proceed to
      DTC P0488 A
      No DTC output B

    B

    END

    A

  13. REPLACE ECM


    1. Replace the ECM Click here.


    NEXT

  14. CONFIRM WHETHER MALFUNCTION HAS BEEN SUCCESSFULLY REPAIRED


    1. Connect the intelligent tester to the DLC3.

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

    3. Clear DTCs Click here.

    4. Turn the ignition switch off and wait for 1 minute or more.

    5. Turn the ignition switch to ON.

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

    7. Confirm that the DTC is not output again.


    NEXT

    END