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


DTC No. Detection Item DTC Detection Condition Trouble Area Note
U0235 Lost Communication with Cruise Control Front Distance Range Sensor No communication from the Millimeter Wave Radar Sensor Assembly continues.

  • Open or short in sub bus 13 main line or connector

  • Millimeter wave radar sensor assembly

  • Power source circuit of millimeter wave radar sensor assembly

  • Millimeter wave radar sensor assembly ground circuit

Tech Tips

The driving support ECU assembly stores DTCs when it detects a communication stop or network communication error for ECUs connected to sub bus 13.
U1002 Lost Communication with Gateway Module (Sensor Bus) The driving support ECU assembly cannot receive signals from all ECUs that have been memorized as those connected to sub bus 13.

  • Open or short in sub bus 13 main line or connector

  • Driving support ECU assembly

  • Power source circuit of driving support ECU assembly

  • Driving support ECU assembly ground circuit

  • Millimeter wave radar sensor assembly

  • Power source circuit of millimeter wave radar sensor assembly

  • Millimeter wave radar sensor assembly ground circuit

Tech Tips

The driving support ECU assembly stores DTCs when it detects a communication stop or network communication error for ECUs connected to sub bus 13.

Tech Tips

The diagnostic procedure is for when DTC U1002 is output by the driving support ECU assembly (GTS display: Pre-Crash2).

WIRING DIAGRAM

B0075M2E13

CAUTION / NOTICE / HINT

Note


  • Before measuring the resistance of the CAN bus, turn the engine switch off and leave the vehicle for 1 minute or more without operating the key or any switches, or opening or closing the doors. After that, disconnect the cable from the negative (-) battery terminal and leave the vehicle for 1 minute or more before measuring the resistance.

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

    Click here

  • Because the order of diagnosis is important to allow correct diagnosis, make sure to begin troubleshooting using How to Proceed with Troubleshooting when CAN communication system related DTCs are output.

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  • After the repair, perform the CAN bus check and check that all the ECUs and sensors connected to the CAN communication system are displayed.

    Click here

Tech Tips


  • Operating the engine 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. RECONFIRM DTC OUTPUT


    1. Reconfirm DTCs.


      Body Electrical > Gateway > Trouble Codes
      Result
      Result Proceed to
      DTC U0104 not output from the network gateway ECU (GTS display: Gateway) A
      DTC U0104 is output from the network gateway ECU (GTS display: Gateway) B

    B

    GO TO DIAGNOSTIC PROCEDURE INDICATED BY OUTPUT DTC Click here

    A

  2. CHECK SUB BUS 13


    1. Turn the engine switch off.

    2. Disconnect the cable from the negative (-) battery terminal.

    3. B007624C07
      *1 DLC3
      *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
      Q1-40 (CA1P) - Q1-18 (CA1N) Cable disconnected from negative (-) battery terminal 54 to 69 Ω Below 54 Ω: Short circuit between bus lines
      70 Ω or more: Open circuit in main bus lines
      Q1-40 (CA1P) - Q1-25 (GND) Cable disconnected from negative (-) battery terminal 200 Ω or higher Below 200 Ω: CANH short to ground
      Q1-18 (CA1N) - Q1-25 (GND) Cable disconnected from negative (-) battery terminal 200 Ω or higher Below 200 Ω: CANL short to ground
      Q1-40 (CA1P) - O8-16 (BAT) Cable disconnected from negative (-) battery terminal 6 kΩ or higher Below 6 kΩ: CANH +B short
      Q1-18 (CA1N) - O8-16 (BAT) Cable disconnected from negative (-) battery terminal 6 kΩ or higher Below 6 kΩ: CANL +B short
      Result
      Result Proceed to
      OK A
      Open circuit in CAN main bus lines B
      Short circuit between bus lines C

      • Short to ground

      • +B short

      		 D

    B

    CHECK FOR OPEN IN SUB BUS 13 MAIN LINES (DRIVING SUPPORT ECU ASSEMBLY) Click here

    C

    CHECK FOR SHORT IN SUB BUS 13 LINES (DRIVING SUPPORT ECU ASSEMBLY) Click here

    D

    CHECK FOR SHORT IN SUB BUS 13 LINE (DRIVING SUPPORT ECU ASSEMBLY) Click here

    A

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


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

      Click here

      Result
      Result
      OK
      NG

    NG

    REPAIR OR REPLACE POWER SOURCE CIRCUIT (MILLIMETER WAVE RADAR SENSOR ASSEMBLY)

    OK

  4. CHECK FOR DTC OUTPUT


    1. Reconnect the cable to the negative (-) battery terminal.

    2. Connect the GTS to the DLC3.

    3. Turn the engine switch on (IG).

    4. Turn the GTS on.

    5. Clear the DTCs.


      Body Electrical > Pre-Crash 2 > Clear DTCs

    6. Turn the engine switch off.

    7. Turn the engine switch on (IG).

    8. Check for DTCs.


      Body Electrical > Pre-Crash 2 > Trouble Codes
      Result
      Result Proceed to
      DTC U1002 not output from the driving support ECU assembly (GTS display: Pre-Crash 2) A
      DTC U1002 is output from the driving support ECU assembly (GTS display: Pre-Crash 2) B

    A

    SYMPTOM SIMULATION Click here

    B

  5. REPLACE DRIVING SUPPORT ECU ASSEMBLY


    1. Replace the driving support ECU assembly.

      Click here

      Result
      Result
      NEXT

    NEXT

  6. CHECK FOR DTC OUTPUT


    1. Reconnect the cable to the negative (-) battery terminal.

    2. Turn the engine switch off.

    3. Turn the engine switch on (IG).

    4. Check for DTCs.


      Body Electrical > Pre-Crash 2 > Trouble Codes
      Result
      Result Proceed to
      DTC U1002 is output from the driving support ECU assembly (GTS display: Pre-Crash 2) A
      DTC U1002 not output from the driving support ECU assembly (GTS display: Pre-Crash 2) B

    A

    END

    B

    REPLACE MILLIMETER WAVE RADAR SENSOR ASSEMBLY Click here

  7. CHECK FOR OPEN IN SUB BUS 13 MAIN LINES (DRIVING SUPPORT ECU ASSEMBLY)


    1. B0072TEC49
      *a

      Front view of wire harness connector

      (to Driving Support ECU Assembly)

      Disconnect the Q1 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
      Q1-40 (CA1P) - Q1-18 (CA1N) Cable disconnected from negative (-) battery terminal 108 to 132 Ω
      Result
      Result
      OK
      NG

    OK

    REPLACE DRIVING SUPPORT ECU ASSEMBLY Click here

    NG

  8. CHECK FOR OPEN IN SUB BUS 13 MAIN LINES (MILLIMETER WAVE RADAR SENSOR ASSEMBLY)


    1. Reconnect the Q1 driving support ECU assembly connector.

    2. B007695C67
      *a

      Front view of wire harness connector

      (to Millimeter Wave Radar Sensor Assembly)

      Disconnect the B7 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
      B7-3 (CA1P) - B7-2 (CA1N) Cable disconnected from negative (-) battery terminal 108 to 132 Ω
      Result
      Result
      OK
      NG

    OK

    REPLACE MILLIMETER WAVE RADAR SENSOR ASSEMBLY Click here

    NG

    REPAIR OR REPLACE CAN MAIN BUS LINES OR CONNECTOR

  9. CHECK FOR SHORT IN SUB BUS 13 LINES (DRIVING SUPPORT ECU ASSEMBLY)


    1. B0072TEC50
      *a

      Front view of wire harness connector

      (to Driving Support ECU Assembly)

      Disconnect the Q1 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
      Q1-40 (CA1P) - Q1-18 (CA1N) Cable disconnected from negative (-) battery terminal 108 to 132 Ω
      Result
      Result
      OK
      NG

    OK

    REPLACE DRIVING SUPPORT ECU ASSEMBLY Click here

    NG

  10. CHECK FOR SHORT IN SUB BUS 13 LINES (MILLIMETER WAVE RADAR SENSOR ASSEMBLY)


    1. Reconnect the Q1 driving support ECU assembly connector.

    2. B007695C68
      *a

      Front view of wire harness connector

      (to Millimeter Wave Radar Sensor Assembly)

      Disconnect the B7 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
      B7-3 (CA1P) - B7-2 (CA1N) Cable disconnected from negative (-) battery terminal 108 to 132 Ω
      Result
      Result
      OK
      NG

    OK

    REPLACE MILLIMETER WAVE RADAR SENSOR ASSEMBLY Click here

    NG

    REPAIR OR REPLACE CAN MAIN BUS LINES OR CONNECTOR

  11. CHECK FOR SHORT IN SUB BUS 13 LINE (DRIVING SUPPORT ECU ASSEMBLY)


    1. Disconnect the Q1 driving support ECU assembly connector.

    2. B0076MJC06
      *1 DLC3
      *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 Result
      Q1-40 (CA1P) - Q1-25 (GND) Cable disconnected from negative (-) battery terminal 200 Ω or higher Below 200 Ω: CANH short to ground
      Q1-18 (CA1N) - Q1-25 (GND) Cable disconnected from negative (-) battery terminal 200 Ω or higher Below 200 Ω: CANL short to ground
      Q1-40 (CA1P) - O8-16 (BAT) Cable disconnected from negative (-) battery terminal 6 kΩ or higher Below 6 kΩ: CANH +B short
      Q1-18 (CA1N) - O8-16 (BAT) Cable disconnected from negative (-) 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 Sub Bus 13 inspection.

      • Find the necessary inspection from the Result column that matches the result in the Result column from the Check Sub Bus 13 inspection.

      Result
      Result
      OK
      NG

    OK

    REPLACE DRIVING SUPPORT ECU ASSEMBLY Click here

    NG

  12. CHECK FOR SHORT IN SUB BUS 13 LINE (MILLIMETER WAVE RADAR SENSOR ASSEMBLY)


    1. Reconnect the Q1 driving support ECU assembly connector.

    2. B0077GYC06
      *1 DLC3
      *a

      Front view of wire harness connector

      (to Millimeter Wave Radar Sensor Assembly)

      Disconnect the B7 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 Result
      B7-3 (CA1P) - O8-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher Below 200 Ω: CANH short to ground
      B7-2 (CA1N) - O8-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher Below 200 Ω: CANL short to ground
      B7-3 (CA1P) - O8-16 (BAT) Cable disconnected from negative (-) battery terminal 6 kΩ or higher Below 6 kΩ: CANH +B short
      B7-2 (CA1N) - O8-16 (BAT) Cable disconnected from negative (-) 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 Sub Bus 13 inspection.

      • Find the necessary inspection from the Result column that matches the result in the Result column from the Check Sub Bus 13 inspection.

      Result
      Result
      OK
      NG

    OK

    REPLACE MILLIMETER WAVE RADAR SENSOR ASSEMBLY Click here

    NG

    REPAIR OR REPLACE CAN MAIN BUS LINE OR CONNECTOR