ECD SYSTEM(w/ DPF), Diagnostic DTC:P0405, P0406

DTC Code DTC Name
P0405 Exhaust Gas Recirculation Sensor "A" Circuit Low
P0406 Exhaust Gas Recirculation Sensor "A" Circuit High

DESCRIPTION

The EGR system is designed to reduce and control NOx formation by means of a reduction of peak temperature in the engine combustion chamber, which is accomplished by introducing an inert gas into intake manifold.

Exhaust gases are redirected to the EGR valve, and when the valve opens, the gases are circulated into the intake manifold by difference in the pressure between exhaust manifold and intake manifold.

The ECM judges engine condition from engine speed (NE) and injection amount and operates the EGR valve with the DC motor and controls the amount of EGR gas. Also, it controls diesel throttle opening position with the DC motor. By using the engine coolant temperature sensor and atmospheric sensor, the EGR system can operate according to various driving conditions.

Adopting an exhaust gas passage in the cylinder head and a water cooling type EGR cooler makes it possible to lower the temperature of the exhaust gas and recirculate a large amount of exhaust gas.

P0405
DTC Detection Drive Pattern DTC Detection Condition Trouble Area
Ignition switch ON for 3 seconds

Open or short in EGR valve position sensor circuit

(1 trip detection logic)

  • Electric EGR control valve assembly

  • Open or short in EGR valve position sensor circuit

  • ECM
P0406
DTC Detection Drive Pattern DTC Detection Condition Trouble Area
Ignition switch ON for 3 seconds

Open or short in EGR valve position sensor circuit

(1 trip detection logic)

  • Electric EGR control valve assembly

  • Open or short in EGR valve position sensor circuit

  • ECM

WIRING DIAGRAM

Refer to DTC P0403 Click here.

CAUTION / NOTICE / HINT

Note

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 GTS. Then after installing the new ECM, perform all of the initialization/registrations 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 HARNESS AND CONNECTOR (ELECTRIC EGR CONTROL VALVE ASSEMBLY - ECM)


    1. Disconnect the B55 electric EGR control valve assembly connector.

    2. Disconnect the B104 ECM connector (for LHD).

    3. Disconnect the B103 ECM connector (for RHD).

    4. Measure the resistance according to the value(s) in the table below.

      Standard Resistance
      for LHD
      Tester Connection Condition Specified Condition
      B55-5 (VC) - B104-64 (VCEG) Always Below 1 Ω
      B55-4 (VTA) - B104-79 (EGLS) Always Below 1 Ω
      B55-3 (E2) - B104-111 (EEGL) Always Below 1 Ω
      B55-5 (VC) or B104-64 (VCEG) - Body ground Always 10 kΩ or higher
      B55-4 (VTA) or B104-79 (EGLS) - Body ground Always 10 kΩ or higher
      B55-3 (E2) or B104-111 (EEGL) - Body ground Always 10 kΩ or higher
      for RHD
      Tester Connection Condition Specified Condition
      B55-5 (VC) - B103-64 (VCEG) Always Below 1 Ω
      B55-4 (VTA) - B103-79 (EGLS) Always Below 1 Ω
      B55-3 (E2) - B103-111 (EEGL) Always Below 1 Ω
      B55-5 (VC) or B103-64 (VCEG) - Body ground Always 10 kΩ or higher
      B55-4 (VTA) or B103-79 (EGLS) - Body ground Always 10 kΩ or higher
      B55-3 (E2) or B103-111 (EEGL) - Body ground Always 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR Click here

    OK

  2. CHECK TERMINAL VOLTAGE (VC VOLTAGE)


    1. A01VH8GE01
      Text in Illustration
      *a

      Front view of wire harness connector

      (to Electric EGR Control Valve Assembly)

      Disconnect the electric EGR control valve assembly connector.

    2. Turn the ignition switch to ON.

    3. Measure the voltage according to the value(s) in the table below.

      Standard Voltage
      Tester Connection Switch Condition Specified Condition
      B55-5 (VC) - B55-3 (E2) Ignition switch ON 4.5 to 5.5 V

    NG

    REPLACE ECM Click here

    OK

  3. REPLACE ELECTRIC EGR CONTROL VALVE ASSEMBLY


    1. Replace electric EGR control 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 WHETHER DTC OUTPUT RECURS (DTC P0405 OR P0406) Click here

  4. REPAIR OR REPLACE HARNESS OR CONNECTOR


    NEXT

  5. CHECK WHETHER DTC OUTPUT RECURS (DTC P0405 OR P0406)


    1. Connect the GTS to the DLC3.

    2. Turn the ignition switch to ON.

    3. Turn the GTS on.

    4. Clear the DTCs Click here.

    5. Turn the ignition switch off and wait for 30 seconds.

    6. Turn the ignition switch to ON and wait for 15 seconds or more.

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

    8. Read the DTCs.

      Result
      Result Proceed to
      DTC is not output A
      DTC P0405 or P0406 is output B

    A

    END

    B

  6. REPLACE ECM


    1. Replace the ECM Click here.


    NEXT

  7. CONFIRM WHETHER MALFUNCTION HAS BEEN SUCCESSFULLY REPAIRED


    1. Connect the GTS to the DLC3.

    2. Turn the ignition switch to ON.

    3. Turn the GTS on.

    4. Clear the DTCs Click here.

    5. Turn the ignition switch off and wait for 30 seconds.

    6. Turn the ignition switch to ON and wait for 15 seconds or more.

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

    8. Confirm that the DTC is not output again.


    NEXT

    END