Dtc P0400 Exhaust Gas Recirculation Flow


DESCRIPTION

MONITOR DESCRIPTION

INSPECTION PROCEDURE

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

PERFORM ACTIVE TEST USING GTS (ACTIVATE THE EGR VALVE CLOSE)

READ VALUE USING GTS (MAF)

PERFORM ACTIVE TEST USING GTS (ACTIVATE THE VSV FOR EGR COOLER BYPASS)

PERFORM ACTIVE TEST USING GTS (ACTIVATE THE VSV FOR EGR COOLER BYPASS)

CHECK WHETHER DTC OUTPUT RECURS (DTC P0400)

REPLACE MASS AIR FLOW METER SUB-ASSEMBLY

CHECK FOR DEPOSIT (ELECTRIC EGR CONTROL VALVE ASSEMBLY)

REPLACE NO. 1 EGR COOLER

CHECK WHETHER DTC OUTPUT RECURS (DTC P0400)

DTC P0400 Exhaust Gas Recirculation Flow


DESCRIPTION

The EGR system recirculates exhaust gases. The recirculated gas mingles with the intake air so that the EGR system can 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.

P0400
DTC Detection Drive Pattern
DTC Detection Condition
Trouble Area
After warming up the engine, decelerate from a speed of 80 km/h (50 mph) or more (fully release the accelerator pedal for approximately 5 seconds).
Mass air flow rate is not changed when turning on the electric EGR control valve assembly while decelerating.
(2 trip detection logic)
  1. EGR valve deposit
  2. EGR valve passage deposit
  3. EGR cooler assembly
  4. Mass air flow meter sub-assembly

Related Data List
DTC No.
Data List
P0400
  1. MAF
  2. Target EGR Valve Pos
  3. Actual EGR Valve Pos

MONITOR DESCRIPTION

If the EGR valve is forcibly operated during deceleration but the intake air amount does not vary, the ECM determines that the EGR valve is malfunctioning. The ECM then illuminates the MIL (2 trip detection logic).

Land Cruiser, Land Cruiser Prado. Grj150 Trj150,155 Kdj150,155 Lj150, Gdj150,155.1Gd-Ftv Engine Control.Ecd System. Dtc P0400 Exhaust Gas Recirculation Flow


INSPECTION PROCEDURE

NOTICE:
After replacing the ECM, the new ECM needs registration (LandCruiser RM0000012XK0AUX.html) and initialization (LandCruiser RM000000TIN08HX.html).
HINT:
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.
1.CHECK FOR ANY OTHER DTCS OUTPUT (IN ADDITION TO DTC P0400)

  1. Connect the GTS to the DLC3.

  1. Turn the engine switch on (IG) and turn the GTS on.

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

  1. Read the DTCs.

    Result
    Result
    		Proceed to
    DTC P0400 is output
    		A
    DTC P0400 and other DTCs are output
    		B


B
GO TO DTC CHART (LandCruiser RM0000031HW07OX.html)
A


2.PERFORM ACTIVE TEST USING GTS (ACTIVATE THE EGR VALVE CLOSE)

  1. Connect the GTS to the DLC3.

  1. Start the engine and warm it up, and make sure the A/C switch and all accessory switches are off.

  1. Turn the engine switch off. Wait for 30 seconds, and then restart the engine.

  1. Turn the GTS on.

  1. Enter the following menus: Powertrain / Engine and ECT / Data List / MAF.

  1. Read the MAF value displayed on the GTS while the engine is idling.

  1. Enter the following menus: Powertrain / Engine and ECT / Active Test / Activate the EGR Valve Close.

  1. Read the MAF value when the EGR valve is closed using the Active Test function.

    HINT:
    1. If idling continues for 20 minutes or more, the EGR valve target opening angle becomes 0% (EGR valve fully closed). As this makes diagnosis impossible, it becomes necessary to drive the vehicle or to restart the engine.
    2. Before performing the diagnosis, confirm that the EGR valve target opening angle is not 0%.
    3. When idling the engine, the EGR cooler sub-assembly is bypassed.

    Result
    Active Test
    		Result
    		Proceed to
    Activate the EGR Valve Close:
    Off (Open) to On (Closed)
    		MAF value does not change
    		A
    MAF value changes
    		B
    NOTICE:
    As the measured values may differ from those shown below due to factors such as differences in measuring environments and changes in vehicle condition due to aging, do not use these values to determine whether the vehicle is malfunctioning or not.
    HINT:
    The problem may be a temporary one, due to the entry of deposits or foreign matter. Check that there are no deposits or foreign matter in the electric EGR control valve assembly or mass air flow meter.

    Reference:

    EGR Valve Condition (Opening)
    		Measuring Condition
    		MAF (Reference)
    Open (41%)
    1. Atmosphere pressure: 101 kPa
    2. Engine coolant temperature: 75°C (167°F)
    		3 to 7 gm/sec
    Closed (0%)
    		11 to 16 gm/sec


B
Go to step 5
A


3.READ VALUE USING GTS (MAF)

  1. Connect the GTS to the DLC3.

  1. Turn the engine switch on (IG) and turn the GTS on.

  1. Enter the following menus: Powertrain / Engine and ECT / Data List / MAF.

  1. Start the engine and read the value when 30 seconds has elapsed.

    Standard:

    GTS Display
    		Switch Condition
    		Standard
    MAF
    		Idling
    1. 3.0 to 15.0 gm/sec (EGR on)
    2. 10.0 to 21.0 gm/sec (EGR off)
    Running without load (3000 rpm):
    1. 45.0 to 89.0 gm/sec (EGR on)
    2. 72.0 to 94.0 gm/sec (EGR off)


NG
Go to step 7
OK


4.PERFORM ACTIVE TEST USING GTS (ACTIVATE THE VSV FOR EGR COOLER BYPASS)

  1. Connect the GTS to the DLC3.

  1. Start the engine and warm it up, and make sure the A/C switch and all accessory switches are off.

  1. Turn the engine switch off and wait for 30 seconds.

  1. Start the engine and turn the GTS on.

  1. Enter the following menus: Powertrain / Engine and ECT / Data List / MAF.

  1. Read the MAF value displayed on the GTS while the engine is idling.

  1. Enter the following menus: Powertrain / Engine and ECT / Active Test / Activate the VSV for EGR Cooler Bypass / Data List / EGR Cooler Bypass Position.

    HINT:
    Whether the EGR is passing through the bypass side or cooler side during the Active Test can be confirmed by checking EGR Cooler Bypass Position.

  1. Using the Active Test function, switch the EGR valve bypass switching valve between "Cooler" and "Bypass" a few times, and then check whether the MAF value changes after switching the valve from "Cooler" to "Bypass".

    HINT:
    If idling continues for 20 minutes or more, the EGR valve target opening angle becomes 0% (EGR valve fully closed). As this makes diagnosis impossible, it becomes necessary to drive the vehicle or restart the engine.

    Result
    GTS Display
    		Result
    		Proceed to
    Activate the VSV for EGR Cooler Bypass:
    Cooler to Bypass
    		MAF value does not change
    		A
    MAF value changes
    		B
    HINT:
    If the No. 1 EGR cooler is clogged, the mass air flow changes.


A
Go to step 8

B
Go to step 9

5.PERFORM ACTIVE TEST USING GTS (ACTIVATE THE VSV FOR EGR COOLER BYPASS)

  1. Connect the GTS to the DLC3.

  1. Start the engine and warm it up, and make sure the A/C switch and all accessory switches are off.

  1. Turn the engine switch off and wait for 30 seconds.

  1. Start the engine and turn the GTS on.

  1. Enter the following menus: Powertrain / Engine and ECT / Data List / MAF.

  1. Read the MAF value displayed on the GTS while the engine is idling.

  1. Enter the following menus: Powertrain / Engine and ECT / Active Test / Activate the VSV for EGR Cooler Bypass / Data List / EGR Cooler Bypass Position.

    HINT:
    Whether the EGR is passing through the bypass side or cooler side during the Active Test can be confirmed by checking EGR Cooler Bypass Position.

  1. Using the Active Test function, switch the EGR valve bypass switching valve between "Cooler" and "Bypass" a few times, and then check whether the MAF value changes after switching the valve from "Cooler" to "Bypass".

    HINT:
    1. If idling continues for 20 minutes or more, the EGR valve target opening angle becomes 0% (EGR valve fully closed). As this makes diagnosis impossible, it becomes necessary to drive the vehicle or restart the engine.
    2. When operating "Activate the VSV for EGR Cooler Bypass", check that "Cooler" and "Bypass" can be switched between and the EGR cooler by-pass valve regulating link operates. If the link does not operate, the inspection cannot be performed correctly. Therefore, inspect and repair the following parts, perform the Active Test and read the changes in the MAF value.
      1. No. 2 EGR valve assembly (LandCruiser RM000005UDV000X_01_0007.html).
      2. Vacuum hose connection (LandCruiser RM000005UDV000X_01_0004.html).
      3. No. 1 vacuum switching valve assembly (for EGR bypass valve) (LandCruiser RM000005UJX000X.html).

    Result
    GTS Display
    		Result
    		Proceed to
    Activate the VSV for EGR Cooler Bypass:
    Cooler to Bypass
    		MAF value does not change
    		A
    MAF value changes
    		B
    HINT:
    If the No. 1 EGR cooler is clogged, the mass air flow changes.


B
Go to step 9
A


6.CHECK WHETHER DTC OUTPUT RECURS (DTC P0400)

  1. Connect the GTS to the DLC3.

  1. Turn the engine switch on (IG) and turn the GTS on.

  1. Clear the DTCs (LandCruiser RM000000PDK1E5X.html).

  1. Turn the engine switch off for 30 seconds or more.

  1. Start the engine and warm it up.

  1. Move the shift lever to 2nd gear and decelerate from a speed of 50 km/h (31 mph) or more (fully release the accelerator for approximately 5 seconds or more).

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

  1. Read the DTCs.

    HINT:
    When a DTC is output, the mass air flow meter sub-assembly may be malfunctioning.

NEXT

END

7.REPLACE MASS AIR FLOW METER SUB-ASSEMBLY

  1. Replace the mass air flow meter sub-assembly (LandCruiser RM000000VHD05PX.html).

    HINT:
    If foreign matter is stuck inside the mass air flow meter sub-assembly, the output characteristics of the mass air flow meter sub-assembly may change, resulting in a malfunction.


NEXT
Go to step 10

8.CHECK FOR DEPOSIT (ELECTRIC EGR CONTROL VALVE ASSEMBLY)

  1. Remove the electric EGR control valve assembly (LandCruiser RM000005UJR000X.html).

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

    NOTICE:
    1. When cleaning the electric EGR control valve, make sure the valve is completely closed.
    2. Do not forcibly open the valve, as it may be damaged or deformed.
    3. When cleaning the electric EGR control valve, use a piece of cloth soaked with cleaning solvent. Spraying the solvent directly onto these parts or soaking the parts in the solvent may damage the parts.
    4. When cleaning the EGR control valve, care should be taken to prevent the ingress of cleaning solvent into the bearings of valve shaft, and when wiping off deposits on the EGR control valve, care should be taken not to push the deposits into the bearings of valve shaft. These contaminants may adversely affect the function of EGR control valve.
    HINT:
    1. If the EGR valve does not open properly or is stuck closed, the amount of intake air increases and combustion sounds and engine vibration may increase.
    2. If the EGR valve does not close properly or is stuck open, EGR becomes excessive and combustion becomes unstable. Also, there may be a lack of power.

  1. Reinstall the electric EGR control valve assembly (LandCruiser RM000005UJO000X.html).


NEXT


9.REPLACE NO. 1 EGR COOLER

  1. Replace the No. 1 EGR cooler (LandCruiser RM000005UJV000X.html).


NEXT


10.CHECK WHETHER DTC OUTPUT RECURS (DTC P0400)

  1. Connect the GTS to the DLC3.

  1. Turn the engine switch on (IG) and turn the GTS on.

  1. Clear the DTCs (LandCruiser RM000000PDK1E5X.html).

  1. Turn the engine switch off for 30 seconds or more.

  1. Start the engine and warm it up.

  1. Move the shift lever to 2nd gear and decelerate from a speed of 50 km/h (31 mph) or more (fully release the accelerator for approximately 5 seconds or more).

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

  1. Read the DTCs.

    HINT:
    When a DTC is output, the mass air flow meter may sub-assembly be malfunctioning.

NEXT

END