CAN COMMUNICATION SYSTEM, Diagnostic DTC:U1002, U0235

DTC Code DTC Name
U1002 Lost Communication with Gateway Module (Sensor Bus)
U0235 Lost Communication with Cruise Control Front Distance Range Sensor

DESCRIPTION

The driving support ECU assembly will store this DTC when no signals can be received from the ECUs that have been memorized as those that are connected to the sensor bus.

DTC No. DTC Detection Condition Trouble Area
U1002 Driving support ECU assembly cannot receive signals from all ECUs that have been memorized as those connected to the sensor bus.

  • Open or short in sensor bus main wire or connector

  • Driving support ECU assembly

  • Millimeter wave radar sensor assembly
U0235 No communication from the millimeter wave radar sensor assembly continues.

  • Open or short in sensor bus main wire or connector

  • Driving support ECU assembly

  • Millimeter wave radar sensor assembly

Tech Tips

The diagnosis procedure is for when DTC U1002 is output by the driving support ECU assembly (Intelligent Tester display: Pre-Crash 2).

WIRING DIAGRAM

A003VJUE01

INSPECTION PROCEDURE

Note


  • After turning the power switch off, waiting time may be required before disconnecting the cable from the negative (-) auxiliary battery terminal. Therefore, make sure to read the disconnecting the cable from the negative (-) auxiliary battery terminal notice before proceeding with work Click here.

  • Turn the power switch off before measuring the resistances between CAN main bus lines and between CAN branch lines.

  • Turn the power switch off before inspecting CAN bus lines for a ground short.

  • After the power switch is turned off, check that the key reminder warning system and light reminder warning system are not operating.

  • Before measuring the resistance, leave the vehicle as is for at least 1 minute and do not operate the power switch, any other switches or the doors. If any doors need to be opened in order to check connectors, open the doors and leave them open.

Tech Tips


  • Operating the power switch, any other switches or a door triggers related ECU and sensor communication on the CAN. This communication will cause the resistance value to change.

  • Even after DTCs are cleared, if a DTC is stored again after driving the vehicle for a while, the malfunction may be occurring due to vibration of the vehicle. In such a case, wiggling the ECUs or wire harness while performing the inspection below may help determine the cause of the malfunction.

PROCEDURE


  1. CHECK SENSOR BUS LINES


    1. Disconnect the cable from the negative (-) auxiliary battery terminal.

    2. A003WCME31
      Text in Illustration
      *a

      Component with harness connected

      (Driving Support ECU Assembly)

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

      Standard Resistance
      Tester Connection Condition Specified Condition Result
      H5-40 (CA1P) - H5-18 (CA1N) Cable disconnected from negative (-) auxiliary battery terminal 54 to 69 Ω

      Below 54 Ω:

      Short circuit between bus lines

      70 Ω or more:

      Open circuit in a main bus line
      H5-40 (CA1P) - H5-25 (GND) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher

      Below 200 Ω:

      CANH ground short
      H5-18 (CA1N) - H5-25 (GND) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher

      Below 200 Ω:

      CANL ground short

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

      Standard Resistance
      Tester Connection Condition Specified Condition Result
      H5-40 (CA1P) - H5-30 (B) Cable disconnected from negative (-) auxiliary battery terminal 6 kΩ or higher

      Below 6 kΩ:

      CANH +B short
      H5-18 (CA1N) - H5-30 (B) Cable disconnected from negative (-) auxiliary battery terminal 6 kΩ or higher

      Below 6 kΩ:

      CANL +B short
      Result
      Result Proceed to
      OK A

      • Open circuit in CAN main bus line

      • Short circuit between bus lines

      		 B

      • Ground short

      • +B short

      		 C

    B

    CHECK FOR SENSOR BUS MAIN LINES (DRIVING SUPPORT ECU ASSEMBLY) Click here

    C

    CHECK FOR SHORT IN SENSOR BUS MAIN LINE (DRIVING SUPPORT ECU ASSEMBLY) Click here

    A

  2. CHECK FOR POWER SOURCE CIRCUIT (MILLIMETER WAVE RADAR SENSOR ASSEMBLY)


    1. Check the millimeter wave radar sensor assembly power source circuit Click here.


    NG

    REPAIR OR REPLACE CORRESPONDING AREA

    OK

    REPLACE DRIVING SUPPORT ECU ASSEMBLY Click here

  3. CHECK FOR SENSOR BUS MAIN LINES (DRIVING SUPPORT ECU ASSEMBLY)


    1. A003VZUE08
      Text in Illustration
      *a

      Front view of wire harness connector

      (to Driving Support ECU Assembly)

      Disconnect the H5 driving support ECU assembly connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      H5-40 (CA1P) - H5-18 (CA1N) Cable disconnected from negative (-) auxiliary battery terminal 108 to 132 Ω

    NG

    CHECK FOR SENSOR BUS MAIN LINES (MILLIMETER WAVE RADAR SENSOR ASSEMBLY) Click here

    OK

    REPLACE DRIVING SUPPORT ECU ASSEMBLY Click here

  4. CHECK FOR SENSOR BUS MAIN LINES (MILLIMETER WAVE RADAR SENSOR ASSEMBLY)


    1. Reconnect the H5 driving support ECU assembly connector.

    2. A003YOME05
      Text in Illustration
      *a

      Front view of wire harness connector

      (to Millimeter Wave Radar Sensor Assembly)

      Disconnect the A2 millimeter wave radar sensor assembly connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A2-4 (CA1P) - A2-3 (CA1N) Cable disconnected from negative (-) auxiliary battery terminal 108 to 132 Ω

    NG

    REPAIR OR REPLACE CAN MAIN BUS LINE (DRIVING SUPPORT ECU ASSEMBLY - MILLIMETER WAVE RADAR SENSOR ASSEMBLY)

    OK

    REPLACE MILLIMETER WAVE RADAR SENSOR ASSEMBLY Click here

  5. CHECK FOR SHORT IN SENSOR BUS MAIN LINE (DRIVING SUPPORT ECU ASSEMBLY)


    1. Disconnect the H5 driving support ECU assembly connector.

    2. A003VZUE09
      Text in Illustration
      *a

      Front view of wire harness connector

      (to Driving Support ECU Assembly)

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

      Standard Resistance
      Tester Connection Condition Specified Condition Purpose
      H5-40 (CA1P) - H5-25 (GND) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher

      Below 200 Ω:

      CANH ground short
      H5-18 (CA1N) - H5-25 (GND) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher

      Below 200 Ω:

      CANL ground short
      H5-40 (CA1P) - H5-30 (B) Cable disconnected from negative (-) auxiliary battery terminal 6 kΩ or higher

      Below 6 kΩ:

      CANH +B short
      H5-18 (CA1N) - H5-30 (B) Cable disconnected from negative (-) auxiliary battery terminal 6 kΩ or higher

      Below 6 kΩ:

      CANL +B short

      Tech Tips

      It is only necessary to perform the inspection in the above table for the result (short circuit) that was obtained in the Check Sensor Bus Lines inspection.

      Find the necessary inspection from the Purpose column that matches the result in the Result column from the Check Sensor Bus Lines inspection.


    NG

    CHECK FOR SHORT IN SENSOR BUS MAIN LINE (MILLIMETER WAVE RADAR SENSOR ASSEMBLY) Click here

    OK

    REPLACE DRIVING SUPPORT ECU ASSEMBLY Click here

  6. CHECK FOR SHORT IN SENSOR BUS MAIN LINE (MILLIMETER WAVE RADAR SENSOR ASSEMBLY)


    1. Disconnect the A2 millimeter wave radar sensor assembly connector.

    2. A003YLME15
      Text in Illustration
      *1 DLC3
      *a

      Front view of wire harness connector

      (to Millimeter Wave Radar Sensor Assembly)

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

      Standard Resistance
      Tester Connection Condition Specified Condition Purpose
      A2-4 (CA1P) - H44-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher

      Below 200 Ω:

      CANH ground short
      A2-3 (CA1N) - H44-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher

      Below 200 Ω:

      CANL ground short
      A2-4 (CA1P) - H44-16 (BAT) Cable disconnected from negative (-) auxiliary battery terminal 6 kΩ or higher

      Below 6 kΩ:

      CANH +B short
      A2-3 (CA1N) - H44-16 (BAT) Cable disconnected from negative (-) auxiliary battery terminal 6 kΩ or higher

      Below 6 kΩ:

      CANL +B short

      Tech Tips

      It is only necessary to perform the inspection in the above table for the result (short circuit) that was obtained in the Check Sensor Bus Lines inspection.

      Find the necessary inspection from the Purpose column that matches the result in the Result column from the Check Sensor Bus Lines inspection.


    NG

    REPAIR OR REPLACE CAN MAIN BUS LINE (DRIVING SUPPORT ECU ASSEMBLY - MILLIMETER WAVE RADAR SENSOR ASSEMBLY)

    OK

    REPLACE MILLIMETER WAVE RADAR SENSOR ASSEMBLY Click here