EMISSION CONTROL SYSTEM, Diagnostic DTC:71

DTC Code DTC Name
71 EGR System Malfunction

DESCRIPTION

The EGR system recirculates exhaust gas, which is controlled to the proper quantity to suit the driving conditions, into the intake air mixture so as to slow down combustion, reduce the combustion temperature and reduce NOx emissions,

The lift amount of EGR valve is controlled by the vacuum which is regulated by the E-VRV operated by the emission ECU.

Tech Tips


  • Under the following conditions, EGR is cut to maintain driveability.


  • Before the engine is warmed up


  • During deceleration (Diesel throttle valve closed)


  • Light engine load (amount of intake air very small)


  • Engine speed over 4,000 rpm

DTC No. DTC Detecting Condition Trouble Area
71 When abnormal feedback values have been obtained during EGR control operation (2 trip detection logic)

  • Disconnect clogging or damage age of sensing pipe


  • Vacuum pump


  • EGR valve


  • E-VRV for EGR


  • Open or short in E - VRV circuit


  • Emission ECU

WIRING DIAGRAM

A01KIR4E01

INSPECTION PROCEDURE

PROCEDURE


  1. CHECK VACUUM HOSE


    1. Check the connection of vacuum hose between the vacuum pump and E-VRV for EGR.

    2. Check the connection of vacuum hose between E-VRV for EGR and EGR valve.


    NG

    REPAIR OR REPLACE REPAIR OR REPLACE VACUUM HOSE

    OK

  2. CHECK ELECTRIC EGR CONTROL VALVE ASSEMBLY (OPERATION CHECK)


    1. Disconnect the emission ECU connector.

    2. Turn the ignition switch ON.

    3. Connect terminal EGR of emission ECU connector and body ground (ON).

    4. A01KFXRE02
      Text in Illustration
      *1 E-VRV
      *2 air filter
      *a ON
      *b OFF

      Disconnect terminal EGR of emission ECU connector and body ground (OFF).

      Specification
      E-VRV ON: Air from pipe E flows out through pipe F. E-VRV OFF: Air from pipe E flow is out through air filter.

    OK

    CHECK ELECTRIC EGR CONTROL VALVE ASSEMBLY Click here

    NG

  3. INSPECT ELECTRIC EGR CONTROL VALVE ASSEMBLY

    Click here


    NG

    REPLACE ELECTRIC EGR CONTROL VALVE ASSEMBLY

    OK

  4. CHECK WIRE HARNESS AND CONNECTORS (E-VRV - EMISSION ECU)


    1. Disconnect the E-VRV connector.

    2. Disconnect the emission ECU connector.

    3. A01KH0WE05
      A01KHEG

      Check the continuity between terminals 1 of the E-VRV harness connector and EGR of the ECU connector Click here.

      RESISTANCE
      1 Ω or less

    4. Check for short between terminals 1 of the E-VRV harness connector and EGR of the ECU connector Click here.

      RESISTANCE
      1 MΩ or more

    5. To check wire harness for terminal 2 of E-VRV connector, refer to the wiring diagram.


    NG

    REPAIR OR REPLACE WIRE HARNESS OR CONNECTOR

    OK

    CHECK AND REPLACE EMISSION CONTROL ECU Click here

  5. CHECK ELECTRIC EGR CONTROL VALVE ASSEMBLY


    NG

    REPLACE ELECTRIC EGR CONTROL VALVE ASSEMBLY

    OK

    CHECK FOR PROBLEM SYMPTOMS TABLE Click here