CAN COMMUNICATION SYSTEM (for RHD), Diagnostic DTC:U1100

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

DESCRIPTION

DTC Code DTC Detection Condition Trouble Area
U1100 There is no communication from the seat belt control ECU.
  • Power source or inside of seat belt control ECU

  • Seat belt control ECU CAN branch wire or connector

  • Seat belt control ECU


WIRING DIAGRAM

A01FUIIE04

INSPECTION PROCEDURE

Note


  • 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.

  • 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 auxiliary battery terminal. Therefore, make sure to read the disconnecting the cable from the auxiliary battery terminal notice before proceeding with work Click here.

  • Inspect the fuses for circuits related to this system before performing the following inspection procedure.

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

  • DTC check procedure: Turn the power switch on (IG) and wait at least 20 seconds.

  • 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 power switch, any switches or any doors triggers related ECU and sensor communication with the CAN, which causes resistance variation.

  • 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: w/o Dynamic Rear Steering System

    • *2: w/ Dynamic Rear Steering System


    1. Reconfirm DTCs.

      Tech Tips

      If DTC U1002 is output from Gateway of the network gateway ECU, this indicates a sub bus 2*1 or sub bus 18*2 malfunction. Troubleshoot for DTC U1002 and check for malfunctions in sub bus 2*1 or sub bus 18*2.

      Result
      Result Proceed to
      DTC U1002 is not output from network gateway ECU. A
      DTC U1002 is output from network gateway ECU. B

    B
    A
  2. CHECK FOR OPEN IN CAN BUS WIRE (SEAT BELT CONTROL ECU CAN BRANCH WIRE)


    1. A01FVYOE01
      Text in Illustration
      *a

      Rear view of wire harness connector

      (to Seat Belt Control ECU)

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

    2. Disconnect the 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
      U35-1 (CANH) - U35-2 (CANL) Cable disconnected from negative (-) auxiliary battery terminal 54 to 69 Ω

    NG
    OK
  3. CHECK HARNESS AND CONNECTOR (SEAT BELT CONTROL ECU - BATTERY AND BODY GROUND)


    1. A01FVUDE01
      Text in Illustration
      *a

      Rear view of wire harness connector

      (to Seat Belt Control ECU)

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

      Note

      When connecting the cable, some systems need to be initialized after the cable is reconnected Click here.

    2. Disconnect the seat belt control ECU connector.

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      U34-7 (+B) - Body ground Always 11 to 14 V
      U35-8 (IG1) - Body ground Power switch on (IG) 11 to 14 V
    4. Measure the resistance according to the value(s) in the table below.

      Standard Resistance
      Tester Connection Condition Specified Condition
      U34-8 (PGND) - Body ground Always Below 1 Ω

    NG
    OK