ECD SYSTEM(w/o Glow Plug Controller), 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.

Tip:

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

DTC No.

Detection Item

DTC Detection Condition

Trouble Area

MIL

Memory

P0488

Exhaust Gas Recirculation Throttle Position Control Range / Performance

Condition (A):

  • DC motor duty is higher than specified value for 0.5 seconds.

    (2 trip detection logic)

Condition (B):

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

    (1 trip detection logic)

  • Throttle valve stuck

  • Throttle valve does not move smoothly

  • Open or short in diesel throttle circuit

  • ECM

Condition (A):

-

Condition (B):

Comes on

DTC stored
Table 1. DTC Detection Drive Pattern

DTC No.

DTC Detection Drive Pattern

P0488

With a warm engine, turn the ignition switch from ON to off and wait for 1 minute or more.
Table 2. Related Data List

DTC No.

Data List

P0488

  • Target Throttle Position

  • Actual Throttle Position

  • Throttle Motor DUTY
Table 3. 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
Tip:

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

    • Poor acceleration

    • Lack of power due to a fail-safe operation

    • Combustion noise increases

  • 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, 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 and intake manifold can be checked visually. When checking the electric EGR control valve assembly, hold the EGR valve to a light and confirm that the valve contacts with the valve seat securely.

    A294338C01

    *1

    EGR Pipe Connector

    *2

    Electric EGR Control Valve Assembly

    *3

    Intake Air Connector

    *4

    No. 2 EGR Valve Assembly

    *5

    EGR with Cooler Pipe Assembly

    -

    -

  • If the DPF catalyst has become clogged with PM (Particulate Matter) and the value of the "PM Accumulation Ratio" is more than 149% 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 149% 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 the GTS: Powertrain / Engine and ECT / Data List / PM Accumulation Ratio.

MONITOR DESCRIPTION

Diesel throttle valve malfunction

When the target and actual positions of the throttle valve are different for 60 seconds or more, the ECM interprets this as a malfunction of the throttle valve.

A286044E04

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 solvent directly onto these parts or soaking the parts in solvent may damage the parts.

  • When replacing the ECM, perform ECM Initialization and Registration.

    Click hereClick here

Tip:

  • When the ECM must be replaced, before replacing the ECM, perform the "Learning Values Save" function using the GTS. Then after installing a new ECM, perform all of the initialization and registration procedures for the "Learning Values Write" function by following the instructions shown on the GTS display.

  • 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

      Result

      Proceed to

      DTC P0488 is output

      A

      DTC P0488 and P2100, P2101, P2102 and/or P2103 are output

      B
      Tip:

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

  2. 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 / Data List / 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 continuously the Active Test value at 0, 30, 60, 90, 60, 30 to 0%, check that Actual Throttle Position smoothly changes to the set opening angle.

      OK

      Value smoothly changes to the set opening angle.

    Result

    Proceed to

    OK

    NG
    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.

      Tip:

      If water or water marks exist, water may have frozen in the diesel throttle body assembly, causing the DTC to be stored.

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

      OK

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

    Result

    Proceed to

    OK

    NG
    NG

    REPAIR OR REPLACE VACUUM HOSE AND PIPEClick here

    OK

  4. 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.

      Tip:

      If carbon deposits exist in the diesel throttle body assembly, the following parts possibly also have deposits inside: electric EGR control valve assembly, intake manifold, DPF catalyst, other parts related to the exhaust gas. By removing the electric EGR control valve assembly from the intake manifold, deposit between the electric EGR control valve assembly and intake manifold can be checked for 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.

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

      Note:

      • When cleaning the electric EGR control valve assembly or the diesel throttle body, make sure the valve is completely closed.

      • Do not forcibly open the valve, as it may be damaged or deformed.

      • When cleaning the electric EGR control valve assembly or the diesel throttle body, 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.

    A294337C01

    *1

    Electric EGR Control Valve Assembly

    *2

    Diesel Throttle Body Assembly

    *3

    Intake Air Connector

    -

    -

    Result

    Proceed to

    NEXT
    NEXT

  5. 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.

    Result

    Proceed to

    OK

    NG
    NG

    REPLACE DIESEL THROTTLE BODY ASSEMBLYClick here

    OK

  6. CHECK WHETHER DTC OUTPUT RECURS

    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 and wait for 1 minute or more.

    5. Turn the ignition switch to ON.

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

    7. Read the pending DTCs.

      Powertrain > Engine and ECT > Trouble Codes

      Result

      Result

      Proceed to

      DTC P0488 is output

      A

      DTC is not output

      B
    B

    END

    A

  7. REPLACE ECM

    1. Replace the ECM.

      Click here

    Result

    Proceed to

    NEXT
    NEXT

  8. CONFIRM WHETHER MALFUNCTION HAS BEEN SUCCESSFULLY REPAIRED

    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 and wait for 1 minute or more.

    5. Turn the ignition switch to ON.

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

    7. Confirm that the pending DTC is not output again.

      Powertrain > Engine and ECT > Trouble Codes

    Result

    Proceed to

    NEXT
    NEXT

    END

  9. REPLACE DIESEL THROTTLE BODY ASSEMBLY

    1. Replace the diesel throttle body assembly.

      Click hereClick here

    Result

    Proceed to

    NEXT
    NEXT

    CHECK WHETHER DTC OUTPUT RECURSClick here

  10. REPAIR OR REPLACE VACUUM HOSE AND PIPE

    1. Repair or replace the vacuum hoses or pipes.

    Result

    Proceed to

    NEXT
    NEXT

    CHECK FOR DEPOSIT (DIESEL THROTTLE BODY ASSEMBLY)Click here

  11. 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.

      Tip:

      If carbon deposits exist in the diesel throttle body assembly, the following parts possibly also have deposits inside: electric EGR control valve assembly, intake manifold, DPF catalyst, other parts related to the exhaust gas. By removing the electric EGR control valve assembly from the intake manifold, deposit between the electric EGR control valve assembly and intake manifold can be checked for 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.

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

      Note:

      • When cleaning the electric EGR control valve assembly or the diesel throttle body, make sure the valve is completely closed.

      • Do not forcibly open the valve, as it may be damaged or deformed.

      • When cleaning the electric EGR control valve assembly or the diesel throttle body, 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.

    A294337C01

    *1

    Electric EGR Control Valve Assembly

    *2

    Diesel Throttle Body Assembly

    *3

    Intake Air Connector

    -

    -

    Result

    Proceed to

    NEXT
    NEXT

  12. 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.

    Result

    Proceed to

    OK

    NG
    NG

    REPLACE DIESEL THROTTLE BODY ASSEMBLYClick here

    OK

  13. 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

      B25-2 (M+) - A101-43 (M+)

      Always

      Below 1 Ω

      B25-1 (M-) - A101-42 (M-)

      Always

      Below 1 Ω

      B25-2 (M+) or A101-43 (M+) - Body ground

      Always

      10 kΩ or higher

      B25-1 (M-) or A101-42 (M-) - Body ground

      Always

      10 kΩ or higher

    Result

    Proceed to

    OK

    NG
    OK

    REPLACE DIESEL THROTTLE BODY ASSEMBLYClick here

    NG

  14. REPAIR OR REPLACE HARNESS OR CONNECTOR

    Result

    Proceed to

    NEXT
    NEXT

    CHECK WHETHER DTC OUTPUT RECURSClick here