CAN COMMUNICATION SYSTEM, Diagnostic DTC:U1100

DTC Code DTC Name
U1100 Lost Communication with Seat Belt Control ECU

DESCRIPTION

DTC No. DTC Detection Condition Trouble Area
U1100 No communication from the seat belt control ECU continues.

  • Seat belt control ECU branch line or connector

  • Power source circuit of seat belt control ECU

  • Seat belt control ECU ground circuit

  • Seat belt control ECU

Tech Tips

This diagnosis procedure is for when DTC U1100 is output by the network gateway ECU (GTS display: Gateway).

WIRING DIAGRAM

A01G5NPE03

INSPECTION PROCEDURE

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, 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 Click here.

  • After performing repairs, perform the DTC check procedure and confirm that the DTCs are not output again.

  • DTC check procedure: Turn the engine switch on (IG), wait at least 20 seconds and then drive the vehicle at a speed of 5 km/h (3 mph) or more for 6.2 seconds or more.

  • After the repair, perform 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.

      Tech Tips

      If DTC U1002 is output from Gateway of the network gateway ECU, this indicates a sub bus 2 malfunction. Troubleshoot for DTC U1002 and check for malfunctions in sub bus 2.

      Result
      Result Proceed to
      U1002 is not output from network gateway ECU (GTS display: Gateway) A
      U1002 is output from network gateway ECU (GTS display: Gateway) B

    B

    GO TO DIAGNOSIS PROCEDURE INDICATED BY OUTPUT DTC Click here

    A

  2. CHECK FOR OPEN IN SUB BUS 2 LINES (SEAT BELT CONTROL ECU BRANCH LINE)


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

    2. A01G5S1E30
      Text in Illustration
      *a

      Front view of wire harness connector

      (to Seat Belt Control ECU)

      Disconnect the H78 seat belt control ECU connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      H78-1 (CANH) - H78-2 (CANL) Cable disconnected from negative (-) battery terminal 54 to 69 Ω

    NG

    REPAIR OR REPLACE CAN BRANCH LINE OR CONNECTOR (SEAT BELT CONTROL ECU)

    OK

  3. CHECK HARNESS AND CONNECTOR (POWER SOURCE TERMINAL)


    1. Disconnect the H77 seat belt control ECU connector.

    2. A01G6WBE10
      Text in Illustration
      *a

      Front view of wire harness connector

      (to Seat Belt Control ECU)

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      H77-8 (PGND) - Body ground Cable disconnected from negative (-) battery terminal Below 1 Ω

    3. Connect the cable to the negative (-) battery terminal.

    4. A01G9HOE18
      Text in Illustration
      *a

      Front view of wire harness connector

      (to Seat Belt Control ECU)

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      H77-7 (+B) - Body ground Engine switch off 11 to 14 V
      H78-8 (IG1) - Body ground Engine switch on (IG) 11 to 14 V

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (POWER SOURCE CIRCUIT)

    OK

    REPLACE SEAT BELT CONTROL ECU Click here