Dtc U029D Lost Communication With Nox Sensor A


DESCRIPTION

MONITOR DESCRIPTION

WIRING DIAGRAM

INSPECTION PROCEDURE

CHECK DTC OUTPUT

CHECK NITROGEN OXIDES SENSOR

CHECK HARNESS AND CONNECTOR (NITROGEN OXIDES SENSOR - UREA PUMP CONTROL ECU)

REPAIR NITROGEN OXIDES SENSOR

CLEAR DTC

CHECK DTC OUTPUT

INSPECT NOX PM RELAY

CHECK HARNESS AND CONNECTOR (NITROGEN OXIDES SENSOR - ENGINE RELAY BLOCK, BATTERY - ENGINE RELAY BLOCK)

DTC U029D Lost Communication with NOx Sensor "A"


DESCRIPTION

The urea pump control ECU sends and receives data to and from the nitrogen oxides sensor via local CAN communication.

U029D
DTC Detection Drive Pattern
DTC Detection Condition
Trouble Area
Turn the engine switch on (IG) and wait for 1.6 seconds or more.
Communication stops between the ECM and the nitrogen oxides sensor for 1.6 seconds or more.
  1. Nitrogen oxides sensor
  2. Harness or connector
  3. ECM

MONITOR DESCRIPTION

The ECM stores a DTC when a communication malfunction occurs between the nitrogen oxides sensor and urea pump control ECU.

WIRING DIAGRAM


Land Cruiser, Land Cruiser Prado. Grj150 Trj150,155 Kdj150,155 Lj150, Gdj150,155.1Gd-Ftv Engine Control.Ecd System. Dtc U029D Lost Communication With Nox Sensor A


INSPECTION PROCEDURE

NOTICE:
Inspect the fuses of circuits related to this system before performing the following inspection procedure.
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 DTC OUTPUT

  1. Connect the GTS to the DLC3.

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

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

  1. Check for currently output system DTCs.

    Result:

    Result
    		Proceed to
    DTC U029D is output
    		A
    DTC U029D and other DTCs are output*
    		B
    HINT:
    *If any other DTCs are output, perform troubleshooting for those DTCs first.


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


2.CHECK NITROGEN OXIDES SENSOR

  1. Disconnect the nitrogen oxides sensor connector.

  1. Turn the engine switch on (IG).



    Land Cruiser, Land Cruiser Prado. Grj150 Trj150,155 Kdj150,155 Lj150, Gdj150,155.1Gd-Ftv Engine Control.Ecd System. Dtc U029D Lost Communication With Nox Sensor A

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

    Standard Voltage:
    Tester Connection
    		Condition
    		Specified Condition
    s5-5 (BATT) - s5-4 (GND)
    		Engine switch on (IG)
    		11 to 14 V
    Text in Illustration
    *a
    		Front view of wire harness connector
    (to Nitrogen oxides sensor)


NG
Go to step 7
OK


3.CHECK HARNESS AND CONNECTOR (NITROGEN OXIDES SENSOR - UREA PUMP CONTROL ECU)

  1. Disconnect the nitrogen oxides sensor connector.

  1. Disconnect the urea pump control ECU connector.



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


    Land Cruiser, Land Cruiser Prado. Grj150 Trj150,155 Kdj150,155 Lj150, Gdj150,155.1Gd-Ftv Engine Control.Ecd System. Dtc U029D Lost Communication With Nox Sensor A


    Text in Illustration
    *a
    		Front view of wire harness connector
    (to Nitrogen oxides Sensor)
    		*b
    		Front view of wire harness connector
    (to Urea Pump Control ECU)

    Standard Resistance:

    Tester Connection
    		Condition
    		Specified Condition
    s5-2 (CAN+) - s3-27 (CAN+)
    		Always
    		Below 1 Ω
    s5-3 (CAN-) - s3-26 (CAN-)
    		Always
    		Below 1 Ω
    s5-2 (CAN+) or s3-27 (CAN+) - Body ground and other terminals
    		Always
    		10 kΩ or higher
    s5-3 (CAN-) or s3-26 (CAN-) - Body ground and other terminals
    		Always
    		10 kΩ or higher


NG
REPAIR OR REPLACE HARNESS AND CONNECTOR
OK


4.REPAIR NITROGEN OXIDES SENSOR

  1. Replace the nitrogen oxides sensor (LandCruiser RM000004KGB00NX.html).


NEXT


5.CLEAR DTC

  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.


NEXT


6.CHECK DTC OUTPUT

  1. Connect the GTS to the DLC3.

  1. Turn the engine switch on (IG) wait for 1.6 seconds or more.

  1. Turn the GTS on.

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

  1. Read the DTCs.

    Result:

    Result
    		Proceed to
    No DTC is output
    		A
    DTC U029D is output
    		B


B
REPLACE UREA PUMP CONTROL ECU (LandCruiser RM000005UL6000X.html)
A

END

7.INSPECT NOX PM RELAY

  1. Inspect NOx PM relay (LandCruiser RM00000469101AX_01_0001.html).



NG
REPLACE NOX PM RELAY
OK


8.CHECK HARNESS AND CONNECTOR (NITROGEN OXIDES SENSOR - ENGINE RELAY BLOCK, BATTERY - ENGINE RELAY BLOCK)

  1. Disconnect the nitrogen oxides sensor connector.

  1. Remove the NOx PM relay from the engine relay block.



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


    Land Cruiser, Land Cruiser Prado. Grj150 Trj150,155 Kdj150,155 Lj150, Gdj150,155.1Gd-Ftv Engine Control.Ecd System. Dtc U029D Lost Communication With Nox Sensor A


    Text in Illustration
    *1
    		Engine Relay Block
    		-
    		-
    *a
    		Front view of wire harness connector
    (to Nitrogen oxides sensor)
    		*b
    		Front view of wire harness connector
    (to NOx PM Relay)

    Standard Resistance:

    Tester Connection
    		Condition
    		Specified Condition
    s5-5 (BATT) - NOx PM relay terminal 3
    		Always
    		Below 1 Ω
    s5-4 (GND) - Body ground
    		Always
    		Below 1 Ω
    NOx PM relay terminal 2 - Body ground
    		Always
    		Below 1 Ω
    NOx PM relay terminal 3 or s5-5 (BATT) - Body ground and other terminals
    		Always
    		10 kΩ or higher

  1. 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


NG
REPAIR OR REPLACE HARNESS AND CONNECTOR
OK

GO TO ECM POWER SOURCE CIRCUIT (LandCruiser RM000000TI20AMX.html)