CAN COMMUNICATION SYSTEM (for RHD), Diagnostic DTC:U1103

DTC Code DTC Name
U1103 Lost Communication with Stop and Start Control Module

DESCRIPTION


DTC Code DTC Detection Condition Trouble Area
U1103 Certification ECU (smart key ECU assembly) cannot receive signals from all ECUs that have been memorized as those connected to sub bus 15.

  • Open or short in sub bus 15 main line or connector

  • Certification ECU (smart key ECU assembly)

  • ECM

  • Open or short in No. 5 junction connector

WIRING DIAGRAM

A01FHHQE02

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

  • Before replacing the certification ECU (smart key ECU assembly), refer to the entry and start system (for Entry Function) Click here.

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

  • DTC check procedure: Wait 20 seconds after turning the engine switch on (ACC) or on (IG).

  • 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 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. CHECK SUB BUS 15


    1. A01FIHHE01
      Text in Illustration
      *a

      Component with harness connected

      (Certification ECU [Smart Key ECU Assembly])

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

      Standard Resistance
      Tester Connection Condition Specified Condition Resistance: Malfunction
      A34-1 (CA3P) - A34-4 (CA3N) Cable disconnected from negative (-) battery terminal 54 to 69 Ω Below 53 Ω: Short in line
      A34-1 (CA3P) - A34-4 (CA3N) Cable disconnected from negative (-) battery terminal 54 to 69 Ω Higher than 70 Ω: Open in CAN main bus line
      A34-1 (CA3P) - A34-2 (+B) Cable disconnected from negative (-) battery terminal 6 kΩ or higher Below 6 kΩ: +B short
      A34-4 (CA3N) - A34-2 (+B) Cable disconnected from negative (-) battery terminal 6 kΩ or higher Below 6 kΩ: +B short
      A34-1 (CA3P) - A34-11 (E) Cable disconnected from negative (-) battery terminal 200 Ω or higher Below 200 Ω: Ground short
      A34-4 (CA3N) - A34-11 (E) Cable disconnected from negative (-) battery terminal 200 Ω or higher Below 200 Ω: Ground short
      Result
      Result Proceed to
      OK A

      • Open circuit in CAN main bus line

      • Short circuit between bus lines

      		 B

      • Ground short

      • +B short

      		 C

    B

    CHECK FOR OPEN IN CAN BUS LINES (CERTIFICATION ECU) Click here

    C

    CHECK FOR SHORT IN CAN BUS LINES (CERTIFICATION ECU) Click here

    A

  2. CHECK FOR DTC OUTPUT


    1. Clear the DTCs.

    2. Turn the engine switch off.

    3. Turn the engine switch on (IG) and recheck for DTCs.

      Result
      Result Proceed to
      U1002 is output from certification ECU (smart key ECU assembly) (GTS display / Entry&Start) A
      Other DTC is output B

    B

    GO TO DIAGNOSIS PROCEDURE INDICATED BY OUTPUT DTC

    A

    REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)

  3. CHECK FOR OPEN IN CAN BUS LINES (CERTIFICATION ECU)


    1. A01FEV3E01
      Text in Illustration
      *a

      Rear view of wire harness connector

      (to Certification ECU [Smart Key ECU Assembly])

      Disconnect the certification ECU (smart key ECU assembly) connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A34-1 (CA3P) - A34-4 (CA3N) Cable disconnected from negative (-) battery terminal 108 to 132 Ω

    NG

    CHECK FOR OPEN IN CAN BUS LINES (NO. 5 JUNCTION CONNECTOR) Click here

    OK

    REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)

  4. CHECK FOR OPEN IN CAN BUS LINES (NO. 5 JUNCTION CONNECTOR)


    1. A01FIKIE82
      Text in Illustration
      *a

      Rear view of wire harness connector

      (to No. 5 Junction Connector)
      *b to ECM
      *c to Certification ECU (Smart Key ECU Assembly)

      Reconnect the certification ECU (smart key ECU assembly) connector.

    2. Disconnect the wire harness connector from the No. 5 junction connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      N129-9 (CANH) - N129-20 (CANL) Cable disconnected from negative (-) battery terminal 108 to 132 Ω
      N129-11 (CANH) - N129-22 (CANL) Cable disconnected from negative (-) battery terminal 108 to 132 Ω
      Result
      Result Proceed to
      OK A
      NG (to Certification ECU main bus line) B
      NG (to ECM main bus line) C

    B

    REPAIR OR REPLACE CAN MAIN BUS LINE OR CONNECTOR (NO. 5 JUNCTION CONNECTOR - CERTIFICATION ECU)

    C

    CHECK FOR OPEN IN CAN BUS LINES (ECM) Click here

    A

    REPLACE NO. 5 JUNCTION CONNECTOR

  5. CHECK FOR OPEN IN CAN BUS LINES (ECM)


    1. A01FGQ0E04
      Text in Illustration
      *a

      Rear view of wire harness connector

      (to ECM)

      Reconnect the wire harness connector from the No. 5 junction connector.

    2. Disconnect the ECM connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A21-12 (CANP) - A12-11 (CANN) Cable disconnected from negative (-) battery terminal 108 to 132 Ω
      Result
      Result Proceed to
      OK (for 2GR-FSE) A
      OK (for 4GR-FSE) B
      NG C

    B

    REPLACE ECM Click here

    C

    REPAIR OR REPLACE CAN MAIN BUS LINE OR CONNECTOR (ECM - NO. 5 JUNCTION CONNECTOR)

    A

    REPLACE ECM Click here

  6. CHECK FOR SHORT IN CAN BUS LINES (CERTIFICATION ECU)


    1. A01FFSPE01
      Text in Illustration
      *a

      Rear view of wire harness connector

      (to Certification ECU [Smart Key ECU Assembly])
      *b Front view of DLC3

      Disconnect the certification ECU (smart key ECU assembly) connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A34-1 (CA3P) - N20-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher
      A34-4 (CA3N) - N20-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher
      A34-1 (CA3P) - N20-16 (BAT) Cable disconnected from negative (-) battery terminal 6 kΩ or higher
      A34-4 (CA3N) - N20-16 (BAT) Cable disconnected from negative (-) battery terminal 6 kΩ or higher

    NG

    CHECK FOR SHORT IN CAN BUS LINES (NO. 5 JUNCTION CONNECTOR) Click here

    OK

    REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)

  7. CHECK FOR SHORT IN CAN BUS LINES (NO. 5 JUNCTION CONNECTOR)


    1. Reconnect the certification ECU (smart key ECU assembly) connector.

      A01FE57E18
      Text in Illustration
      *a

      Rear view of wire harness connector

      (to No. 5 Junction Connector)

      		 *b Front view of DLC3
      *c to ECM *d to Certification ECU (Smart Key ECU Assembly)

    2. Disconnect the wire harness connector from the No. 5 junction connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition Purpose Connected to
      N129-9 (CANH) - N20-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher Inspection for CANH ground short Certification ECU (smart key ECU assembly)
      N129-20 (CANL) - N20-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher Inspection for CANL ground short
      N129-11 (CANH) - N20-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher Inspection for CANH ground short ECM
      N129-22 (CANL) - N20-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher Inspection for CANL ground short
      N129-9 (CANH) - N20-16 (BAT) Cable disconnected from negative (-) battery terminal 6 kΩ or higher Inspection for CANH +B short Certification ECU (smart key ECU assembly)
      N129-20 (CANL) - N20-16 (BAT) Cable disconnected from negative (-) battery terminal 6 kΩ or higher Inspection for CANL +B short
      N129-11 (CANH) - N20-16 (BAT) Cable disconnected from negative (-) battery terminal 6 kΩ or higher Inspection for CANH +B short ECM
      N129-22 (CANL) - N20-16 (BAT) Cable disconnected from negative (-) battery terminal 6 kΩ or higher Inspection for CANL +B short
      Result
      Result Proceed to
      OK A
      NG (to Certification ECU main bus line) B
      NG (to ECM main bus line) C

    B

    REPAIR OR REPLACE CAN MAIN BUS LINE OR CONNECTOR (NO. 5 JUNCTION CONNECTOR - CERTIFICATION ECU)

    C

    CHECK FOR SHORT IN CAN BUS LINES (ECM) Click here

    A

    REPLACE NO. 5 JUNCTION CONNECTOR

  8. CHECK FOR SHORT IN CAN BUS LINES (ECM)


    1. A01FGWNE06
      Text in Illustration
      *a

      Rear view of wire harness connector

      (to ECM)
      *b Front view of DLC3

      Disconnect the ECM connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A21-12 (CANP) - N20-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher
      A21-11 (CANN) - N20-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher
      A21-12 (CANP) - N20-16 (BAT) Cable disconnected from negative (-) battery terminal 6 kΩ or higher
      A21-11 (CANN) - N20-16 (BAT) Cable disconnected from negative (-) battery terminal 6 kΩ or higher
      Result
      Result Proceed to
      OK (for 2GR-FSE) A
      OK (for 4GR-FSE) B
      NG C

    B

    REPLACE ECM Click here

    C

    REPAIR OR REPLACE CAN MAIN BUS LINE OR CONNECTOR (ECM - NO. 5 JUNCTION CONNECTOR)

    A

    REPLACE ECM Click here