ECD SYSTEM(w/ Urea SCR System), Diagnostic DTC:U029D

DTC Code DTC Name
U029D Lost Communication with NOx Sensor "A"

DESCRIPTION

The ECM sends and receives data to and from the nitrogen oxides sensor assembly via local CAN communication.

DTC No. Detection Item DTC Detection Condition Trouble Area MIL Memory
U029D Lost Communication with NOx Sensor "A" Communication stops between the ECM and the nitrogen oxides sensor assembly for 1.6 seconds or more (1 trip detection logic).

  • Nitrogen oxides sensor assembly

  • Harness or connector

  • ECM

 Comes on DTC stored

MONITOR DESCRIPTION

The ECM stores a DTC when a communication malfunction occurs between the nitrogen oxides sensor assembly and ECM.

CONFIRMATION DRIVING PATTERN

DTC No. DTC Detection Drive Pattern
U029D Ignition switch ON and wait for 1.6 seconds or more.

WIRING DIAGRAM

B00282QE01

CAUTION / NOTICE / HINT

Note

Inspect the fuses of circuits related to this system before performing the following inspection procedure.

Tech Tips

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 DTC OUTPUT


    1. Connect the GTS to the DLC3.

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

    3. According to the display on the GTS, select "Health Check".

    4. Check for currently output system DTCs.

      Result
      Result Proceed to
      DTC U029D is output A
      DTC U029D and other DTCs are output* B

      Tech Tips

      *: If any other DTCs are output, perform troubleshooting for those DTCs first.


    B

    GO TO DTC CHART Click here

    A

  2. CHECK NITROGEN OXIDES SENSOR ASSEMBLY


    1. Disconnect the nitrogen oxides sensor assembly connector.

    2. Turn the ignition switch to ON.

    3. B0027OQC01
      *a

      Front view of wire harness connector

      (to Nitrogen Oxides Sensor Assembly )

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      e1-5 (BATT) - e1-4 (GND) Ignition switch ON 11 to 14 V
      Result
      Proceed to
      OK
      NG

    NG

    INSPECT NOX PM RELAY Click here

    OK

  3. CHECK HARNESS AND CONNECTOR (NITROGEN OXIDES SENSOR ASSEMBLY - ECM)


    1. Disconnect the nitrogen oxides sensor 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
      e1-2 (CAN+) - G85-27 (CANU) Always Below 1 Ω
      e1-3 (CAN-) - G85-35 (CAND) Always Below 1 Ω
      e1-2 (CAN+) or G85-27 (CANU) - Body ground and other terminals Always 10 kΩ or higher
      e1-3 (CAN-) or G85-35 (CAND) - Body ground and other terminals Always 10 kΩ or higher
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS AND CONNECTOR

    OK

  4. REPLACE NITROGEN OXIDES SENSOR ASSEMBLY


    1. Replace the nitrogen oxides sensor assembly.

      Click here

      Result
      Proceed to
      NEXT

    NEXT

  5. CHECK DTC OUTPUT


    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 > Clear DTCs

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

    5. Turn the ignition switch to ON and wait for 1.6 seconds or more.

    6. Turn the GTS on.

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

    8. Read the DTCs.


      Powertrain > Engine > Trouble Codes
      Result
      Result Proceed to
      No DTC is output A
      DTC U029D is output B

    A

    END

    B

    REPLACE ECM Click here

  6. INSPECT NOX PM RELAY


    1. Inspect the NOX PM relay.

      Click here

      Result
      Proceed to
      OK
      NG

    NG

    REPLACE NOX PM RELAY

    OK

  7. CHECK HARNESS AND CONNECTOR (NO. 6 INSTRUMENT PANEL RELAY BLOCK - NITROGEN OXIDES SENSOR ASSEMBLY, BATTERY)


    1. Disconnect the nitrogen oxides sensor assembly connector.

    2. Remove the NOX PM relay from the No. 6 instrument panel relay block.

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

      B00265RC01
      *1 No. 6 Instrument Panel Relay Block - -
      *a

      Front view of wire harness connector

      (to Nitrogen Oxides Sensor Assembly)

      		 *b

      Front view of wire harness connector

      (to NOX PM Relay)
      Standard Resistance
      Tester Connection Condition Specified Condition
      e1-5 (BATT) - NOX PM relay terminal 3 Always Below 1 Ω
      e1-4 (GND) - Body ground Always Below 1 Ω
      NOX PM relay terminal 2 - Body ground Always Below 1 Ω
      NOX PM relay terminal 3 or e1-5 (BATT) - Body ground and other terminals Always 10 kΩ or higher

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      NOX PM relay terminal 5 - Body ground Always 11 to 14 V
      Result
      Proceed to
      OK
      NG

    OK

    GO TO ECM POWER SOURCE CIRCUIT Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR