СИСТЕМА ECD, Diagnostic DTC:P0400

DESCRIPTION

The EGR system recirculates exhaust gases back to the combustion chambers. The recirculated gas is intermixed with the intake air to slow combustion speed and keep the combustion temperature down. This helps reduce NOx emissions.

In order to increase EGR circulation efficiency, the ECM adjusts the EGR valve angle and the throttle valve angle.

MONITOR DESCRIPTION

Either of the following conditions is met:

EGR valve malfunction

When the target and actual positions of the EGR valve are different, the ECM interprets this as a malfunction of the EGR valve and illuminates the MIL.

Flow malfunction

If the target and actual mass air flow rates are different, the ECM determines that the EGR valve is malfunctioning.

WIRING DIAGRAM

Refer to DTC P0405 Click here.

INSPECTION PROCEDURE

PROCEDURE

1. CHECK ANY OTHER DTCS OUTPUT (IN ADDITION TO DTC P0400)

   
   

   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 P0400	A
      DTC P0400 and other DTCs	B

      Tech Tips

      If any DTCs other than P0400 are output, troubleshoot those DTCs first.

   
   

   B

   GO TO DTC CHART Click here

   A

2. CHECK FREEZE FRAME DATA (TARGET EGR POSITION AND ACTUAL EGR VALVE POS.)

   
   

   1. Connect the intelligent tester to the DLC3.

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

   3. Read the values of Target EGR Position and Actual EGR Valve Pos. in Freeze Frame Data.

      Standard
      Actual EGR Valve Pos. is within +/-1% of Target EGR Position.

   
   

   OK

   CHECK FOR EXHAUST GAS LEAKS Click here

   NG

   INSPECT ELECTRIC EGR CONTROL VALVE ASSEMBLY (FULL CLOSE) Click here

3. CHECK FOR EXHAUST GAS LEAKS

   
   

   1. Check for exhaust gas leaks.

      Result

      Result	Proceed to
      Exhaust gas leaks out from exhaust system	A
      No leaks	B

   
   

   B

   CHECK AIR INDUCTION SYSTEM (AIR LEAKS AND BLOCKAGES) Click here

   A

4. REPAIR EXHAUST GAS LEAKAGE POINT

   
   

   1. Repair or replace the malfunctioning part in the exhaust system.

   
   

   NEXT

5. CHECK AIR INDUCTION SYSTEM (AIR LEAKS AND BLOCKAGES)

   
   

   1. Check for air leaks and blockages in the air intake system.

      Result

      Result	Proceed to
      Leaks or blockages exist in the air intake system	A
      No leaks and blockages in the intake system	B

      Tech Tips

      
      

      • Check for abnormal disconnection, pipe and hose squashing, and any damages in the intake system.

      • Using your hand, check whether the pipes and hoses in the intake system are securely connected.

      • Applying soapy water and revving the engine, air leaks from the intake system can be checked.

      • Check for any modifications in the intake system made by the user.

   
   

   B

   CHECK FOR DEPOSIT (EGR PASSAGE) Click here

   A

6. REPAIR OR REPLACE AIR INDUCTION SYSTEM

   
   

   1. Repair or replace the malfunctioning part in the air intake system.

   
   

   NEXT

   CHECK FOR DEPOSIT (EGR PASSAGE) Click here

7. INSPECT ELECTRIC EGR CONTROL VALVE ASSEMBLY (FULL CLOSE)

   
   

   1. Remove the electric EGR valve assembly.

   2. Visually check the electric EGR control valve for deposits. If there are deposits, clean the electric EGR control valve.

      Note

      
      

      • When cleaning the electric EGR control valve, make sure the valve is completely closed.

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

   3. Hold the electric EGR control valve up to a light, and then from the side indicated by the arrow in the illustration, visually check that there is no gap between the valve and body.

      OK
      No light passes through (there is no gap between the valve and body).

      

      Tech Tips

      
      

      • Hold the EGR valve to a light and confirm that the valve contacts with the valve seat securely.

      • If light leaks out from the valve, the EGR valve is not fully closed.

      • If the EGR valve cannot close fully, hesitation or poor acceleration almost certainly has occurred while driving the vehicle.

      • Even if the EGR valve is closed completely, light leaks from the closed gap of valve seat (A part) as shown in the illustration, but this is normal.

   
   

   OK

   PERFORM ACTIVE TEST USING INTELLIGENT TESTER (CONTROL THE EGR STEP POSITION) Click here

   NG

   REPLACE ELECTRIC EGR CONTROL VALVE ASSEMBLY Click here

8. REPLACE ELECTRIC EGR CONTROL VALVE ASSEMBLY

   
   

   1. Replace the electric EGR valve assembly Click here.

      Tech Tips

      Install the new electric EGR valve assembly after the inspection of EGR valve operation (next step).

   2. Connect the electric EGR valve assembly connector.

   3. Turn the ignition switch to ON.

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

   
   

   NEXT

9. PERFORM ACTIVE TEST USING INTELLIGENT TESTER (CONTROL THE EGR STEP POSITION)

   
   

   1. With the EGR valve assembly removed from the vehicle, connect the EGR valve connector.

   2. Connect the intelligent tester to the DLC3.

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

   4. Enter the following menus: Powertrain / Engine and ECT / Active Test / Control the EGR Step Position / Data List / Actual EGR Valve Pos.

   5. When changing the Active Test value for 0, 25, 50, 75 and 100%, check that Actual EGR Valve Pos. smoothly changes to the set opening angle.

      OK
      Value smoothly changes to the set opening angle.

      Tech Tips

      
      

      • EGR valve closed: Actual EGR Valve Pos. is 0%

      • EGR valve open: Actual EGR Valve Pos. is 100%

   
   

   OK

   CHECK FOR DEPOSIT (EGR PASSAGE) Click here

   NG

   CHECK HARNESS AND CONNECTOR (ELECTRIC EGR VALVE ASSEMBLY - ECM) Click here

10. CHECK HARNESS AND CONNECTOR (ELECTRIC EGR VALVE ASSEMBLY - ECM)

    
    

    1. Disconnect the electric EGR valve assembly connector.

    2. 

       *1	Front view of wire harness connector (to Electric EGR Valve Assembly)
       *2	Front view of wire harness connector (to ECM)

       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 B50-5 (VC) - B9-26 (VCEG) Always Below 1 Ω B50-4 (VTA) - B9-27 (EGLS) Always Below 1 Ω B50-3 (E2) - B9-25 (EEGL) Always Below 1 Ω B50-2 (M-) - B9-22 (EGM-) Always Below 1 Ω B50-1 (M+) - B9-23 (EGM+) Always Below 1 Ω

       Standard Resistance (Check for Short)
       Tester Connection Condition Specified Condition B50-5 (VC) or B9-26 (VCEG) - Body ground Always 10 kΩ or higher B50-4 (VTA) or B9-27 (EGLS) - Body ground Always 10 kΩ or higher B50-2 (M-) or B9-22 (EGM-) - Body ground Always 10 kΩ or higher B50-1 (M+) or B9-23 (EGM+) - Body ground Always 10 kΩ or higher

    4. Reconnect the electric EGR valve assembly connector.

    5. Reconnect the ECM connector.

    
    

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR Click here

    OK

11. REPLACE ELECTRIC EGR CONTROL VALVE ASSEMBLY

    Tech Tips

    If the EGR valve assembly has already been replaced, proceed to next step.

    
    

    1. Replace the electric EGR valve assembly Click here.

    2. Turn the ignition switch to ON.

    3. Turn the ignition switch off and wait for 30 seconds or more.

    
    

    NEXT

    CHECK FOR DEPOSIT (EGR PASSAGE) Click here

12. REPAIR OR REPLACE HARNESS OR CONNECTOR

    
    

    NEXT

13. CHECK FOR DEPOSIT (EGR PASSAGE)

    
    

    1. Check the deposit conditions in the electric EGR valve assembly and the EGR passage of the intake manifold.

       

       Result

       Result	Proceed to
       Wet carbon exists	A
       Dry carbon exists	B

       Tech Tips

       
       

       • Wet carbon: Tar carbon that is sticky, or shiny carbon that is hard and smooth to the touch.

       • Dry carbon: Carbon that is dried, not shiny, and peels easily.

       • If wet carbon deposit exists in the EGR valve and EGR passage, an EGR valve slow response malfunction may occur in the EGR valve operation due to sticky carbon deposit. In this case, hesitation or poor acceleration will occur while driving the vehicle.

    
    

    B

    REMOVE DEPOSIT (CLEAN EGR PASSAGE) Click here

    A

14. REPLACE ELECTRIC EGR CONTROL VALVE ASSEMBLY

    Tech Tips

    If the EGR valve assembly has already been replaced, proceed to next step.

    
    

    1. Replace the electric EGR valve assembly Click here.

    2. Turn the ignition switch to ON.

    3. Turn the ignition switch off and wait for 30 seconds or more.

    
    

    NEXT

    CHECK FOR CAUSE OF FAILURE Click here

15. REMOVE DEPOSIT (CLEAN EGR PASSAGE)

    
    

    1. Remove the electric EGR valve assembly, diesel throttle body assembly, intake air connector and EGR pipe connector.

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

       Note

       
       

       • When cleaning the EGR valve and 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.

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

       Tech Tips

       
       

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

       • Do not leave any deposits in the EGR valve assembly when cleaning the valve.

    3. Reinstall the electric EGR valve assembly, diesel throttle body assembly, intake air connector and EGR pipe connector.

    
    

    NEXT

16. CHECK FOR CAUSE OF FAILURE

    Tech Tips

    If causes of black smoke emissions are in the engine, the exhaust system easily clogs with carbon deposits. Check for black smoke emissions in the exhaust gas, and repair the cause of black smoke, if repair is necessary.

    
    

    1. Start the engine and warm it up.

    2. Turn the ignition switch off.

    3. Connect the intelligent tester to the DLC3.

    4. Read the values of the Data List items when the engine is under the following conditions.

       
       

       1. Ignition switch ON (Engine not running).

       2. Idling (after 1 minute or more elapsed)

       3. Engine maintained at 4500 rpm with no load

    5. Take snapshots with the intelligent tester for each engine condition above and analyze the cause of black smoke emission referring to the table below.

       Engine Condition	Data List Item	Standard	Diagnostic Note
       Ignition switch ON	MAP	Difference between MAP and Atmosphere Pressure is +/-7 kPa or less	If the difference exceeds the standard range, the sensor that indicates the value most different from the actual atmospheric pressure is malfunctioning.
       	Atmosphere Pressure
       	Injector Compensation Code*1	The injector compensation codes stored in the ECM match the injector compensation codes of the installed fuel injectors.	If the codes do not match, input the correct codes referring to "Registration".
       Idling	Injection Feedback Val #1 Injection Feedback Val #2 Injection Feedback Val #3 Injection Feedback Val #4	-2.0 to 2.0 mm3/st	The injector for which the value is out of standard range is malfunctioning.
       	Injection Volume	Less than 8 mm3/st	-
       	Coolant Temp	75°C (167°F) or more: After warming up the engine When the engine is stopped and left overnight, the engine coolant temperature should be nearly equal to the intake air temperature.	If the value is out of standard range, check the engine coolant temperature sensor circuit.
       4500 rpm with no load	MAP and Target Booster Pressure	Difference between MAP and Target Booster Pressure is +/-15 kPa or less	If the values are out of standard range, check the following items. Intake system (leaks or blockages) Turbocharger sub-assembly Mass air flow meter circuit Turbo pressure sensor circuit
       	Corrected MAF value*2	66.75 +/-13.4 gm/sec. When the following conditions are met: Engine speed is 4500 rpm MAP is 170 kPa Intake Air Temp (Turbo) is 42°C

       
       

       • *1: Check the Injector Compensation Codes by entering the following menus: Powertrain / Engine and ECT / Utility / Injector Compensation.

       Tech Tips

       
       

       • *2: The MAF value should be corrected by applying the following formula.

         MAF corrected [gm/sec] = MAF measured [gm/sec] x {4500 x 170 x (42 + 273)}/ {Engine Speed [rpm] x MAP [kPa] x (Intake Air Temp (Turbo) + 273)}

       • Example data

         Engine speed: 4800 rpm, MAP: 166 kPa, MAF: 72.0, Intake Air Temp (Turbo): 63°C

         72.0 x {4500 x 170 x (42 + 273)} / {4800 x 166 x (63 + 273)} = 64.81

       • If the value calculated by applying the above formula is higher than the standard, leaks may exist between the turbocharger and the intake manifold.

       • If the value calculated by applying the above formula is lower than the standard, leaks may exist between the air cleaner and the turbocharger.

    6. Check the vacuum hose connection (turbo pressure sensor).

    7. Check for air leaks in the intake pipes and hoses between the turbocharger and the intake manifold.

    8. Check for air leaks in the intake manifold.

    9. Check the turbocharger sub-assembly.

    10. Check for deposit in the EGR cooler.

        

    11. If any malfunctions are found, repair or replace them.

    
    

    NEXT

17. CHECK WHETHER DTC OUTPUT RECURS (DTC P0400)

    
    

    1. Connect the intelligent tester to the DLC3.

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

    3. Clear the DTCs Click here.

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

    5. Start the engine and warm it up.

    6. Taking 10 seconds, depress the accelerator pedal until the engine speed reaches 4000 rpm. (A)

    7. Release the accelerator pedal and allow the engine to idle for 30 seconds. (B)

    8. Repeat (A) and (B) procedures 5 times or more.

    9. Enter the following menus: Powertrain / Engine and ECT / Utility / All Readiness.

    10. Input DTC P0400.

    11. Check the DTC judgment result.

        Result

        Result	Proceed to
        ABNORMAL	A
        NORMAL	B

        Tech Tips

        If STATUS is INCOMPLETE or UNKNOWN, repeat the (A) and (B) driving pattern process 5 times or more.

    
    

    B

    END

    A

18. REPLACE ELECTRIC EGR CONTROL VALVE ASSEMBLY

    Tech Tips

    If the EGR valve assembly has already been replaced, proceed to next step.

    
    

    1. Replace the electric EGR valve assembly Click here.

    2. Turn the ignition switch to ON.

    3. Turn the ignition switch off and wait for 30 seconds or more.

    
    

    NEXT

19. CHECK WHETHER DTC OUTPUT RECURS (DTC P0400)

    
    

    1. Connect the intelligent tester to the DLC3.

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

    3. Clear the DTCs Click here.

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

    5. Start the engine and warm it up.

    6. Taking 10 seconds, depress the accelerator pedal until the engine speed reaches 4000 rpm. (A)

    7. Release the accelerator pedal and allow the engine to idle for 30 seconds. (B)

    8. Repeat (A) and (B) procedures 5 times or more.

    9. Enter the following menus: Powertrain / Engine and ECT / Utility / All Readiness.

    10. Input DTC P0400.

    11. Check the DTC judgment result.

        Result

        Result	Proceed to
        ABNORMAL	A
        NORMAL	B

        Tech Tips

        If STATUS is INCOMPLETE or UNKNOWN, repeat the (A) and (B) driving pattern process 5 times or more.

    
    

    B

    END

    A

20. REPLACE ECM

    
    

    1. Replace the ECM Click here.

    
    

    NEXT

21. 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 the DTCs Click here.

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

    5. Start the engine and warm it up.

    6. Taking 10 seconds, depress the accelerator pedal until the engine speed reaches 4000 rpm. (A)

    7. Release the accelerator pedal and allow the engine to idle for 30 seconds. (B)

    8. Repeat (A) and (B) procedures 5 times or more.

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

    10. Confirm that the DTC is not output again.

        Tech Tips

        Perform the following procedure using the tester to determine whether or not the DTC judgment has been carried out.

        
        

        1. Enter the following menus: Powertrain / Engine and ECT / Utility / All Readiness.

        2. Input DTC P0400.

        3. Check that STATUS is NORMAL. If STATUS is INCOMPLETE or UNKNOWN, repeat the (A) and (B) driving pattern process 5 times or more.

    
    

    NEXT

    END