CAN COMMUNICATION SYSTEM(w/ Central Gateway ECU), 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. DTC Detection Condition Trouble Area
U0235 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
U1002 The driving support ECU assembly cannot receive signals from all ECUs that have been memorized as those connected to the sensor 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 diagnostic procedure is for when DTC U1002 is output by the driving support ECU assembly (GTS display: Pre-crash 2).

WIRING DIAGRAM

A005B4JE03
*a Driving Support ECU Assembly
*b Millimeter Wave Radar Sensor Assembly

CAUTION / NOTICE / HINT

Note


  • Before measuring the resistance of the CAN bus, turn the power 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 (-) auxiliary battery terminal and leave the vehicle for 1 minute or more before measuring the resistance.

  • 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 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 Click here.

  • 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


  • Before disconnecting related connectors for inspection, push in on each connector body to check that the connector is not loose or disconnected.

  • When a connector is disconnected, check that the terminals and connector body are not cracked, deformed or corroded.

PROCEDURE


  1. CHECK SUB BUS 13


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

    2. A005CWUE03
      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
      L60-40 (CA1P) - L60-18 (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 main bus lines
      L60-40 (CA1P) - L60-25 (GND) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher Below 200 Ω: CANH ground short
      L60-18 (CA1N) - L60-25 (GND) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher Below 200 Ω: CANL ground short
      L60-40 (CA1P) - L60-30 (B) Cable disconnected from negative (-) auxiliary battery terminal 6 kΩ or higher Below 6 kΩ: CANH +B short
      L60-18 (CA1N) - L60-30 (B) Cable disconnected from negative (-) auxiliary battery terminal 6 kΩ or higher Below 6 kΩ: CANL +B short
      Result
      Result Proceed to
      OK A
      NG (Open circuit in CAN main bus line) B
      NG (Short circuit between bus lines) C

      • NG (Ground short)

      • NG (+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

  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 POWER SOURCE CIRCUIT (MILLIMETER WAVE RADAR SENSOR ASSEMBLY)

    OK

  3. CHECK FOR DTC OUTPUT


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

    2. Connect the GTS to the DLC3.

    3. Turn the power switch on (IG).

    4. Turn the GTS on.

    5. Clear the DTCs.

    6. Turn the power switch off.

    7. Turn the power switch on (IG).

    8. Check for DTCs.

      Result
      Result Proceed to

      DTC U1002 is 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

  4. REPLACE DRIVING SUPPORT ECU ASSEMBLY


    1. Replace the driving support ECU assembly Click here.


    NEXT

  5. CHECK FOR DTC OUTPUT


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

    2. Turn the power switch off.

    3. Turn the power switch on (IG).

    4. Check for DTCs.

      Result
      Result Proceed to

      DTC U1002 is 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

    END

    B

    REPLACE MILLIMETER WAVE RADAR SENSOR ASSEMBLY Click here

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


    1. A005EK8E02
      Text in Illustration
      *a

      Front view of wire harness connector

      (to Driving Support ECU Assembly)

      Disconnect the L60 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
      L60-40 (CA1P) - L60-18 (CA1N) Cable disconnected from negative (-) auxiliary battery terminal 108 to 132 Ω

    OK

    REPLACE DRIVING SUPPORT ECU ASSEMBLY Click here

    NG

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


    1. Reconnect the L60 driving support ECU assembly connector.

    2. A005A9RE01
      Text in Illustration
      *a

      Front view of wire harness connector

      (to Millimeter Wave Radar Sensor Assembly)

      Disconnect the A76 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
      A76-3 (CA1P) - A76-2 (CA1N) Cable disconnected from negative (-) auxiliary battery terminal 108 to 132 Ω

    OK

    REPLACE MILLIMETER WAVE RADAR SENSOR ASSEMBLY Click here

    NG

    REPAIR OR REPLACE CAN MAIN BUS LINES OR CONNECTOR

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


    1. A005EK8E02
      Text in Illustration
      *a

      Front view of wire harness connector

      (to Driving Support ECU Assembly)

      Disconnect the L60 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
      L60-40 (CA1P) - L60-18 (CA1N) Cable disconnected from negative (-) auxiliary battery terminal 108 to 132 Ω

    OK

    REPLACE DRIVING SUPPORT ECU ASSEMBLY Click here

    NG

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


    1. Reconnect the L60 driving support ECU assembly connector.

    2. A005A9RE01
      Text in Illustration
      *a

      Front view of wire harness connector

      (to Millimeter Wave Radar Sensor Assembly)

      Disconnect the A76 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
      A76-3 (CA1P) - A76-2 (CA1N) Cable disconnected from negative (-) auxiliary battery terminal 108 to 132 Ω

    OK

    REPLACE MILLIMETER WAVE RADAR SENSOR ASSEMBLY Click here

    NG

    REPAIR OR REPLACE CAN MAIN BUS LINES OR CONNECTOR

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


    1. Disconnect the L60 driving support ECU assembly connector.

    2. A005EVCE03
      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 Result
      L60-40 (CA1P) - L60-25 (GND) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher Below 200 Ω: CANH ground short
      L60-18 (CA1N) - L60-25 (GND) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher Below 200 Ω: CANL ground short
      L60-40 (CA1P) - L60-30 (B) Cable disconnected from negative (-) auxiliary battery terminal 6 kΩ or higher Below 6 kΩ: CANH +B short
      L60-18 (CA1N) - L60-30 (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 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.


    OK

    REPLACE DRIVING SUPPORT ECU ASSEMBLY Click here

    NG

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


    1. Reconnect the L60 driving support ECU assembly connector.

    2. A005D9PE02
      Text in Illustration
      *1 DLC3
      *a

      Front view of wire harness connector

      (to Millimeter Wave Radar Sensor Assembly)

      Disconnect the A76 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
      A76-3 (CA1P) - L61-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher Below 200 Ω: CANH ground short
      A76-2 (CA1N) - L61-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher Below 200 Ω: CANL ground short
      A76-3 (CA1P) - L61-16 (BAT) Cable disconnected from negative (-) auxiliary battery terminal 6 kΩ or higher Below 6 kΩ: CANH +B short
      A76-2 (CA1N) - L61-16 (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 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.


    OK

    REPLACE MILLIMETER WAVE RADAR SENSOR ASSEMBLY Click here

    NG

    REPAIR OR REPLACE CAN MAIN BUS LINE OR CONNECTOR