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 wire or connector

  • Power source circuit of seat belt control ECU

  • Seat belt control ECU

WIRING DIAGRAM

A01NE1SE08
A01NDG7E02

INSPECTION PROCEDURE

Note


  • Turn the power switch off before measuring the resistances between CAN bus main wires and between CAN bus branch wires.

  • Turn the power switch off before inspecting CAN bus wires for a ground short.

  • After the power switch is turned off, check that the key reminder warning system and light reminder warning system are not operating.

  • Before measuring the resistance, leave the vehicle as is for at least 1 minute and do not operate the power switch, any other switches or the doors. If any doors need to be opened in order to check connectors, open the doors and leave them open.

Tech Tips


  • 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. RECONFIRM DTC OUTPUT


    1. Reconfirm DTCs.

      Tech Tips

      If CAN No. 2 bus DTC U1002 is output from the power management control ECU (Intelligent tester display/PM1 Gateway), troubleshoot for U1002 and check for malfunctions in the CAN No. 2 main bus circuit.

      Result
      Result Proceed to
      U1002 is not output from power management control ECU (Intelligent tester display/PM1 Gateway) A
      U1002 is output from power management control ECU (Intelligent tester display/PM1 Gateway) B

    B

    GO TO CIRCUITS INDICATED BY OUTPUT DTCS Click here

    A

  2. CHECK CAN BUS WIRE FOR DISCONNECTION (SEAT BELT CONTROL ECU BRANCH WIRE)


    1. Turn the power switch off.

    2. A01NFFIE12
      Text in Illustration
      *1

      Front view of wire harness connector

      (to Seat Belt Control ECU)

      Disconnect the F56 seat belt control ECU connector.

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

      Standard Resistance
      Tester Connection Switch Condition Specified Condition
      F56-1 (CANH) - F56-2 (CANL) Power switch off 54 to 69 Ω

    NG

    REPAIR OR REPLACE SEAT BELT CONTROL ECU BRANCH WIRE OR CONNECTOR (SEAT BELT CONTROL ECU BRANCH WIRE)

    OK

  3. CHECK HARNESS AND CONNECTOR (POWER SOURCE TERMINAL)


    1. Turn the power switch on (IG).

    2. A01NFFIE13
      Text in Illustration
      *1

      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 Switch Condition Specified Condition
      F56-8 (IG1) - Body ground Power switch on (IG) 11 to 14 V

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (POWER SOURCE CIRCUIT)

    OK

  4. CHECK HARNESS AND CONNECTOR (GROUND TERMINAL)


    1. Turn the power switch off.

    2. A01NF0ME01
      Text in Illustration
      *1

      Front view of wire harness connector

      (to Seat Belt Control ECU)

      Disconnect the F57 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
      F57-8 (PGND) - Body ground Always Below 1 Ω

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (GROUND CIRCUIT)

    OK

    REPLACE SEAT BELT CONTROL ECU Click here