CAN COMMUNICATION SYSTEM(for LHD), Diagnostic DTC:U1002

DTC Code DTC Name
U1002 Lost Communication with Gateway Module (Sensor Bus)

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 local bus.

  • When the driving support ECU assembly receives a response signal from the ECUs connected to local bus, the driving support ECU assembly recognizes and memorizes that the ECU is connected to local bus. Based on this memorized data, the driving support ECU assembly monitors for malfunctions in the ECUs connected to local bus when communicating with those ECUs. If the driving support ECU assembly cannot receive response signals from the ECUs that have been memorized as those connected to local bus, the driving support ECU assembly determines that a malfunction exists.

DTC No.

Detection Item

DTC Detection Condition

Trouble Area

DTC Output from

U1002

Lost Communication with Gateway Module (Sensor Bus)

Driving support ECU assembly cannot receive signals from all ECUs that have been memorized as those connected to local bus.

  • Open or short in local bus CAN main wire or connector

  • Open or short in local bus CAN branch wire or connector

  • Driving support ECU assembly

  • Millimeter wave radar sensor assembly

  • Forward recognition camera

  • No. 8 CAN junction connector

Driving support ECU assembly

  • For vehicles with a pre-crash safety system.

WIRING DIAGRAM

C347088E10

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, 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.

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  • 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.

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  • DTC check procedure: Turn the power switch on (IG) and wait at least 6 seconds.

Tip:

  • 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 LOCAL BUS

    1. C339036C03

      *a

      Component with harness connected

      (Driving Support ECU Assembly)

      *b

      Front view of DLC3

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

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

      Standard Resistance

      Tester Connection

      Condition

      Specified Condition

      Resistance: Malfunction

      G168-8 (CA1P) - G168-9 (CA1N)

      Cable disconnected from negative (-) auxiliary battery terminal

      54 to 69 Ω

      Below 53 Ω: Short in line

      G168-8 (CA1P) - G168-9 (CA1N)

      Cable disconnected from negative (-) auxiliary battery terminal

      54 to 69 Ω

      Higher than 70 Ω: Open in CAN main bus line

      G168-8 (CA1P) - G14-16 (BAT)

      Cable disconnected from negative (-) auxiliary battery terminal

      6 kΩ or higher

      Below 6 kΩ: +B short

      G168-9 (CA1N) - G14-16 (BAT)

      Cable disconnected from negative (-) auxiliary battery terminal

      6 kΩ or higher

      Below 6 kΩ: +B short

      G168-8 (CA1P) - G14-4 (CG)

      Cable disconnected from negative (-) auxiliary battery terminal

      200 Ω or higher

      Below 200 Ω: Ground short

      G168-9 (CA1N) - G14-4 (CG)

      Cable disconnected from negative (-) auxiliary battery terminal

      200 Ω or higher

      Below 200 Ω: Ground short

    Result

    Result

    Proceed to

    OK

    A

    NG

    - Open in CAN main wire

    B

    NG

    - Short in CAN bus wire

    C

    NG

    - +B short

    - Ground short

    D
    B

    CHECK FOR OPEN IN CAN BUS MAIN WIRE (NO. 8 CAN JUNCTION CONNECTOR)Click here

    C

    CHECK FOR SHORT IN CAN BUS WIRES (NO. 8 CAN JUNCTION CONNECTOR)Click here

    D

    CHECK FOR SHORT IN CAN BUS WIRES (NO. 8 CAN JUNCTION CONNECTOR)Click here

    A

  2. CHECK FOR DTC

    1. Clear the DTCs.

      Click here

      Body Electrical > Pre-Crash 2 > Clear DTCs

    2. Check for DTCs.

      Click here

      Body Electrical > Pre-Crash 2 > Trouble Codes

    Result

    Result

    Proceed to

    DTC U1002 is output from driving support ECU assembly

    A

    Other DTC is output

    B
    A

    REPLACE DRIVING SUPPORT ECU ASSEMBLY

    Click here

    B

    GO TO DIAGNOSTIC TROUBLE CODE CHART

    Click hereClick here

  3. CHECK FOR OPEN IN CAN BUS MAIN WIRE (NO. 8 CAN JUNCTION CONNECTOR)

    1. C266890C95

      *a

      Rear view of wire harness connector

      (to No. 8 CAN Junction Connector)

      *b

      to Forward Recognition Camera

      *c

      to Millimeter Wave Radar Sensor Assembly

      Disconnect the No. 8 CAN junction connector.

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

      Standard Resistance

      Tester Connection

      Condition

      Specified Condition

      G173-6 (CANH) - G173-17 (CANL)

      Cable disconnected from negative (-) auxiliary battery terminal

      108 to 132 Ω

      G173-7 (CANH) - G173-18 (CANL)

      Cable disconnected from negative (-) auxiliary battery terminal

      108 to 132 Ω

    Result

    Result

    Proceed to

    OK

    A

    NG (to forward recognition camera CAN main wire)

    B

    NG (to millimeter wave radar sensor assembly CAN main wire)

    C
    A

    REPLACE NO. 8 CAN JUNCTION CONNECTOR

    C

    CONNECT CONNECTORClick here

    B

  4. CONNECT CONNECTOR

    1. Reconnect the G173 No. 8 CAN junction connector.

    Result

    Proceed to

    NEXT
    NEXT

  5. CHECK FOR OPEN IN CAN BUS MAIN WIRE (FORWARD RECOGNITION CAMERA - NO. 8 CAN JUNCTION CONNECTOR)

    1. C268302C36

      *a

      Front view of wire harness connector

      (to Forward Recognition Camera)

      Disconnect the forward recognition camera connector.

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

      Standard Resistance

      Tester Connection

      Condition

      Specified Condition

      Q17-6 (CANH) - Q17-12 (CANL)

      Cable disconnected from negative (-) auxiliary battery terminal

      108 to 132 Ω

    Result

    Proceed to

    OK

    NG
    OK

    REPLACE FORWARD RECOGNITION CAMERA

    Click here

    NG

    REPAIR OR REPLACE CAN MAIN WIRE OR CONNECTOR (FORWARD RECOGNITION CAMERA - NO. 8 CAN JUNCTION CONNECTOR)

  6. CONNECT CONNECTOR

    1. Reconnect the G173 No. 8 CAN junction connector.

    Result

    Proceed to

    NEXT
    NEXT

  7. CHECK FOR OPEN IN CAN BUS MAIN WIRE (MILLIMETER WAVE RADAR SENSOR ASSEMBLY - NO. 8 CAN JUNCTION CONNECTOR)

    1. C333439C35

      *a

      Front view of wire harness connector

      (to Millimeter Wave Radar Sensor Assembly)

      Disconnect the millimeter wave radar sensor assembly connector.

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

      Standard Resistance

      Tester Connection

      Condition

      Specified Condition

      Z6-5 (CA1P) - Z6-6 (CA1N)

      Cable disconnected from negative (-) auxiliary battery terminal

      108 to 132 Ω

    Result

    Proceed to

    OK

    NG
    OK

    REPLACE MILLIMETER WAVE RADAR SENSOR ASSEMBLY

    Click here

    NG

    REPAIR OR REPLACE CAN MAIN WIRE OR CONNECTOR (MILLIMETER WAVE RADAR SENSOR ASSEMBLY - NO. 8 CAN JUNCTION CONNECTOR)

  8. CHECK FOR SHORT IN CAN BUS WIRES (NO. 8 CAN JUNCTION CONNECTOR)

    1. C266890C96

      *a

      Rear view of wire harness connector

      (to No. 8 CAN Junction Connector)

      *b

      to Driving Support ECU Assembly

      *c

      to Forward Recognition Camera

      *d

      to Millimeter Wave Radar Sensor Assembly

      Disconnect the No. 8 CAN junction connector.

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

      Standard Resistance

      Tester Connection

      Condition

      Specified Condition

      G173-5 (CANH) - G173-16 (CANL)

      Cable disconnected from negative (-) auxiliary battery terminal

      200 Ω or higher

      G173-6 (CANH) - G173-17 (CANL)

      Cable disconnected from negative (-) auxiliary battery terminal

      108 to 132 Ω

      G173-7 (CANH) - G173-18 (CANL)

      Cable disconnected from negative (-) auxiliary battery terminal

      108 to 132 Ω

    Result

    Result

    Proceed to

    OK

    A

    NG (to forward recognition camera CAN main wire)

    B

    NG (to millimeter wave radar sensor assembly CAN main wire)

    C

    NG (to driving support ECU assembly CAN branch wire)

    D
    A

    REPLACE NO. 8 CAN JUNCTION CONNECTOR

    C

    CONNECT CONNECTORClick here

    D

    CONNECT CONNECTORClick here

    B

  9. CONNECT CONNECTOR

    1. Reconnect the G173 No. 8 CAN junction connector.

    Result

    Proceed to

    NEXT
    NEXT

  10. CHECK FOR SHORT IN CAN BUS WIRES (FORWARD RECOGNITION CAMERA - NO. 8 CAN JUNCTION CONNECTOR)

    1. C268302C36

      *a

      Front view of wire harness connector

      (to Forward Recognition Camera)

      Disconnect the forward recognition camera connector.

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

      Standard Resistance

      Tester Connection

      Condition

      Specified Condition

      Q17-6 (CANH) - Q17-12 (CANL)

      Cable disconnected from negative (-) auxiliary battery terminal

      108 to 132 Ω

    Result

    Proceed to

    OK

    NG
    OK

    REPLACE FORWARD RECOGNITION CAMERA

    Click here

    NG

    REPAIR OR REPLACE CAN MAIN WIRE OR CONNECTOR (FORWARD RECOGNITION CAMERA - NO. 8 CAN JUNCTION CONNECTOR)

  11. CONNECT CONNECTOR

    1. Reconnect the G173 No. 8 CAN junction connector.

    Result

    Proceed to

    NEXT
    NEXT

  12. CHECK FOR SHORT IN CAN BUS WIRES (MILLIMETER WAVE RADAR SENSOR ASSEMBLY - NO. 8 CAN JUNCTION CONNECTOR)

    1. C333439C35

      *a

      Front view of wire harness connector

      (to Millimeter Wave Radar Sensor Assembly)

      Disconnect the millimeter wave radar sensor assembly connector.

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

      Standard Resistance

      Tester Connection

      Condition

      Specified Condition

      Z6-5 (CA1P) - Z6-6 (CA1N)

      Cable disconnected from negative (-) auxiliary battery terminal

      108 to 132 Ω

    Result

    Proceed to

    OK

    NG
    OK

    REPLACE MILLIMETER WAVE RADAR SENSOR ASSEMBLY

    Click here

    NG

    REPAIR OR REPLACE CAN MAIN WIRE OR CONNECTOR (MILLIMETER WAVE RADAR SENSOR ASSEMBLY - NO. 8 CAN JUNCTION CONNECTOR)

  13. CONNECT CONNECTOR

    1. Reconnect the G173 No. 8 CAN junction connector.

    Result

    Proceed to

    NEXT
    NEXT

  14. CHECK FOR SHORT IN CAN BUS WIRES (DRIVING SUPPORT ECU ASSEMBLY - NO. 8 CAN JUNCTION CONNECTOR)

    1. C338465C10

      *a

      Front view of wire harness connector

      (to Driving Support ECU Assembly)

      Disconnect the 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

      G168-8 (CA1P) - G168-9 (CA1N)

      Cable disconnected from negative (-) auxiliary battery terminal

      54 to 69 Ω

    Result

    Proceed to

    OK

    NG
    OK

    REPLACE DRIVING SUPPORT ECU ASSEMBLY

    Click here

    NG

    REPAIR OR REPLACE CAN BRANCH WIRE OR CONNECTOR (DRIVING SUPPORT ECU ASSEMBLY - NO. 8 CAN JUNCTION CONNECTOR)

  15. CHECK FOR SHORT IN CAN BUS WIRES (NO. 8 CAN JUNCTION CONNECTOR)

    1. Disconnect the No. 8 CAN junction connector.

      C300868C48

      *a

      Rear view of wire harness connector

      (to No. 8 CAN Junction Connector)

      *b

      Front view of DLC3

      *c

      to Driving Support ECU Assembly

      *d

      to Forward Recognition Camera

      *e

      to Millimeter Wave Radar Sensor Assembly

      -

      -

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

      Standard Resistance

      Tester Connection

      Condition

      Specified Condition

      G173-5 (CANH) - G14-16 (BAT)

      Cable disconnected from negative (-) auxiliary battery terminal

      6 kΩ or higher

      G173-16 (CANL) - G14-16 (BAT)

      Cable disconnected from negative (-) auxiliary battery terminal

      6 kΩ or higher

      G173-5 (CANH) - G14-4 (CG)

      Cable disconnected from negative (-) auxiliary battery terminal

      200 Ω or higher

      G173-16 (CANL) - G14-4 (CG)

      Cable disconnected from negative (-) auxiliary battery terminal

      200 Ω or higher

      G173-6 (CANH) - G14-16 (BAT)

      Cable disconnected from negative (-) auxiliary battery terminal

      6 kΩ or higher

      G173-17 (CANL) - G14-16 (BAT)

      Cable disconnected from negative (-) auxiliary battery terminal

      6 kΩ or higher

      G173-6 (CANH) - G14-4 (CG)

      Cable disconnected from negative (-) auxiliary battery terminal

      200 Ω or higher

      G173-17 (CANL) - G14-4 (CG)

      Cable disconnected from negative (-) auxiliary battery terminal

      200 Ω or higher

      G173-7 (CANH) - G14-16 (BAT)

      Cable disconnected from negative (-) auxiliary battery terminal

      6 kΩ or higher

      G173-18 (CANL) - G14-16 (BAT)

      Cable disconnected from negative (-) auxiliary battery terminal

      6 kΩ or higher

      G173-7 (CANH) - G14-4 (CG)

      Cable disconnected from negative (-) auxiliary battery terminal

      200 Ω or higher

      G173-18 (CANL) - G14-4 (CG)

      Cable disconnected from negative (-) auxiliary battery terminal

      200 Ω or higher

    Result

    Result

    Proceed to

    OK

    A

    NG (to forward recognition camera CAN main wire)

    B

    NG (to millimeter wave radar sensor assembly CAN main wire)

    C

    NG (to driving support ECU assembly CAN branch wire)

    D
    A

    REPLACE NO. 8 CAN JUNCTION CONNECTOR

    C

    CONNECT CONNECTORClick here

    D

    CONNECT CONNECTORClick here

    B

  16. CONNECT CONNECTOR

    1. Reconnect the G173 No. 8 CAN junction connector.

    Result

    Proceed to

    NEXT
    NEXT

  17. CHECK FOR SHORT IN CAN BUS WIRES (FORWARD RECOGNITION CAMERA - NO. 8 CAN JUNCTION CONNECTOR)

    1. C267485C13

      *a

      Front view of wire harness connector

      (to Forward Recognition Camera)

      *b

      Front view of DLC3

      Disconnect the forward recognition camera connector.

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

      Standard Resistance

      Tester Connection

      Condition

      Specified Condition

      Q17-6 (CANH) - G14-16 (BAT)

      Cable disconnected from negative (-) auxiliary battery terminal

      6 kΩ or higher

      Q17-12 (CANL) - G14-16 (BAT)

      Cable disconnected from negative (-) auxiliary battery terminal

      6 kΩ or higher

      Q17-6 (CANH) - G14-4 (CG)

      Cable disconnected from negative (-) auxiliary battery terminal

      200 Ω or higher

      Q14-12 (CANL) - G14-4 (CG)

      Cable disconnected from negative (-) auxiliary battery terminal

      200 Ω or higher

    Result

    Proceed to

    OK

    NG
    OK

    REPLACE FORWARD RECOGNITION CAMERA

    Click here

    NG

    REPAIR OR REPLACE CAN MAIN WIRE OR CONNECTOR (FORWARD RECOGNITION CAMERA - NO. 8 CAN JUNCTION CONNECTOR)

  18. CONNECT CONNECTOR

    1. Reconnect the G173 No. 8 CAN junction connector.

    Result

    Proceed to

    NEXT
    NEXT

  19. CHECK FOR SHORT IN CAN BUS WIRES (MILLIMETER WAVE RADAR SENSOR ASSEMBLY - NO. 8 CAN JUNCTION CONNECTOR)

    1. C339037C05

      *a

      Front view of wire harness connector

      (to Millimeter Wave Radar Sensor Assembly)

      *b

      Front view of DLC3

      Disconnect the millimeter wave radar sensor assembly connector.

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

      Standard Resistance

      Tester Connection

      Condition

      Specified Condition

      Z6-5 (CA1P) - G14-16 (BAT)

      Cable disconnected from negative (-) auxiliary battery terminal

      6 kΩ or higher

      Z6-6 (CA1N) - G14-16 (BAT)

      Cable disconnected from negative (-) auxiliary battery terminal

      6 kΩ or higher

      Z6-5 (CA1P) - G14-4 (CG)

      Cable disconnected from negative (-) auxiliary battery terminal

      200 Ω or higher

      Z6-6 (CA1N) - G14-4 (CG)

      Cable disconnected from negative (-) auxiliary battery terminal

      200 Ω or higher

    Result

    Proceed to

    OK

    NG
    OK

    REPLACE MILLIMETER WAVE RADAR SENSOR ASSEMBLY

    Click here

    NG

    REPAIR OR REPLACE CAN MAIN WIRE OR CONNECTOR (MILLIMETER WAVE RADAR SENSOR ASSEMBLY - NO. 8 CAN JUNCTION CONNECTOR)

  20. CONNECT CONNECTOR

    1. Reconnect the G173 No. 8 CAN junction connector.

    Result

    Proceed to

    NEXT
    NEXT

  21. CHECK FOR SHORT IN CAN BUS WIRES (DRIVING SUPPORT ECU ASSEMBLY - NO. 8 CAN JUNCTION CONNECTOR)

    1. C339038C04

      *a

      Front view of wire harness connector

      (to Driving Support ECU Assembly)

      *b

      Front view of DLC3

      Disconnect the 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

      G168-8 (CA1P) - G14-16 (BAT)

      Cable disconnected from negative (-) auxiliary battery terminal

      6 kΩ or higher

      G168-9 (CA1N) - G14-16 (BAT)

      Cable disconnected from negative (-) auxiliary battery terminal

      6 kΩ or higher

      G168-8 (CA1P) - G14-4 (CG)

      Cable disconnected from negative (-) auxiliary battery terminal

      200 Ω or higher

      G168-9 (CA1N) - G14-4 (CG)

      Cable disconnected from negative (-) auxiliary battery terminal

      200 Ω or higher

    Result

    Proceed to

    OK

    NG
    OK

    REPLACE DRIVING SUPPORT ECU ASSEMBLY

    Click here

    NG

    REPAIR OR REPLACE CAN BRANCH WIRE OR CONNECTOR (DRIVING SUPPORT ECU ASSEMBLY - NO. 8 CAN JUNCTION CONNECTOR)