CAN COMMUNICATION SYSTEM Certification ECU Communication Stop Mode

DESCRIPTION

Detection Item Symptom Trouble Area
Certification ECU Communication Stop Mode

Either condition is met:


  • "Certification (Smart)" is not displayed on the "CAN Bus Check" screen of the Techstream Click here

  • Communication system DTCs (DTCs that start with U) that correspond to "Certification ECU Communication Stop Mode" in "DTC Combination Table" are output Click here


  • Smart key ECU assembly (Certification ECU) branch line or connector

  • Power source circuit of smart key ECU assembly (Certification ECU)

  • Smart key ECU assembly (Certification ECU) ground circuit

  • Smart key ECU assembly (Certification ECU)

WIRING DIAGRAM

A01HQMUE10

INSPECTION PROCEDURE

Note


  • Before measuring the resistance of the CAN bus, turn the ignition 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 ignition 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 ignition switch to ON, turn the blind spot monitor system on using the blind spot monitor main switch (ON/OFF switch), wait at least 20 seconds and then drive the vehicle at a speed of 6 km/h (4 mph) or more for 6 seconds or more. Check that the warning light remains off after turning off following the initial light check.

  • After the repair, perform the 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 ignition 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 FOR OPEN IN CAN BUS LINES (SMART KEY ECU ASSEMBLY BRANCH LINE)


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

    2. A01HNC5E04
      Text in Illustration
      *a

      Rear view of wire harness connector

      (to Smart Key ECU Assembly (Certification ECU))

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

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      I78-14 (CANH) - I78-15 (CANL) Cable disconnected from negative (-) battery terminal 54 to 69 Ω

    NG

    REPAIR OR REPLACE CAN BRANCH LINE OR CONNECTOR (SMART KEY ECU ASSEMBLY)

    OK

  2. CHECK HARNESS AND CONNECTOR (POWER SOURCE CIRCUIT)


    1. A01HQANE04
      Text in Illustration
      *a

      Rear view of wire harness connector

      (to Smart Key ECU Assembly (Certification ECU))

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A43-11 (E) - Body ground Cable disconnected from negative (-) battery terminal Below 1 Ω

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

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

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

      Standard Voltage
      Tester Connection Switch Condition Specified Condition
      A43-2 (+B) - Body ground Ignition switch off 11 to 14 V
      I78-5 (IG) - Body ground Ignition switch ON 11 to 14 V

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (POWER SOURCE CIRCUIT)

    OK

    REPLACE SMART KEY ECU ASSEMBLY (CERTIFICATION ECU) Click here