CAN COMMUNICATION SYSTEM(w/o Central Gateway ECU) Engine Stop and Start ECU Communication Stop Mode

DESCRIPTION

Detection Item Symptom Trouble Area
Engine Stop and Start ECU Communication Stop Mode

Either condition is met:


  • "Stop and Go/Start" is not displayed on the CAN Bus Check screen of the GTS Click here

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


  • Engine stop and start ECU branch line or connector

  • Power source circuit of engine stop and start ECU

  • Engine stop and start ECU ground circuit

  • Engine stop and start ECU

WIRING DIAGRAM

A01W4U1E02

CAUTION / NOTICE / HINT

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 or any 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) and wait at least 20 seconds.

  • 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.

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

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. CHECK FOR OPEN IN CAN BUS LINES (ENGINE STOP AND START ECU BRANCH LINE)


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

    2. A01W17UE02
      Text in Illustration
      *a

      Front view of wire harness connector

      (to Engine Stop and Start ECU)

      Disconnect the H191 engine stop and start ECU connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      H191-13 (CANH) - H191-14 (CANL) Cable disconnected from negative (-) battery terminal 54 to 69 Ω

    NG

    REPAIR OR REPLACE CAN BRANCH LINE OR CONNECTOR (ENGINE STOP AND START ECU)

    OK

  2. CHECK HARNESS AND CONNECTOR (POWER SOURCE CIRCUIT)


    1. A01W4NXE02
      Text in Illustration
      *a

      Front view of wire harness connector

      (to Engine Stop and Start ECU)

      Disconnect the A76 and A77 engine stop and start ECU connectors.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A76-8 (GND1) - Body ground Cable disconnected from negative (-) battery terminal Below 1 Ω
      A76-2 (GND2) - Body ground Cable disconnected from negative (-) battery terminal Below 1 Ω
      A77-6 (DGND) - Body ground Cable disconnected from negative (-) battery terminal Below 1 Ω

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

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      A77-1 (+B) - Body ground Engine switch on (IG) 11 to 14 V
      H191-19 (ACC) - Body ground Engine switch on (ACC) 11 to 14 V
      H191-21 (IG1) - Body ground Engine switch on (IG) 11 to 14 V
      H191-18 (IG2) - Body ground Engine switch on (IG) 11 to 14 V

    OK

    REPLACE ENGINE STOP AND START ECU Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (POWER SOURCE TERMINAL)