CAN COMMUNICATION SYSTEM ECM Communication Stop Mode

DESCRIPTION

Detection Item Symptom Trouble Area
ECM Communication Stop Mode

Any of the following conditions are met:


  • Communication stop for "ECM (Engine)" is indicated on the "Communication Bus Check" screen of the GTS.

    Click here

  • Communication stop history for "ECM (Engine)" is indicated on the "Communication Bus Check (Detail)" screen of the GTS. (The Lost Communication Time value for "ECM (Engine)" is 6 or more.)

    Click here

  • Communication system DTCs (DTCs that start with U) that correspond to "ECM Communication Stop Mode" in "DTC Combination Table" are output.

    Click here


  • ECM main line or connector

  • Power source circuit of ECM

  • ECM ground circuit

  • ECM

WIRING DIAGRAM

B0071CQE03
for A25A-FKS
*a No. 2 CAN Junction Connector
*b ECU-IG2 NO. 1
*c from IG2 NO. 1 Relay
*d from EFI-MAIN NO. 1 Relay
B006Y61E07
B006Y61E10

CAUTION / NOTICE / HINT

CAUTION:

When performing the confirmation driving pattern, obey all speed limits and traffic laws.

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 ignition 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 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

  • 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 and wait for 1 minute or more. Then operate the suspected malfunctioning system and drive the vehicle at 60 km/h (37 mph) or more for 5 minutes or more.

  • After the repair, perform the CAN bus check and check that all the ECUs and sensors connected to the CAN communication system are displayed as normal.

    Click here

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

Tech Tips


  • Before disconnecting related connectors for inspection, push in on each connector body to check that the connector is not loose or disconnected.

  • When a connector is disconnected, check that the terminals and connector body are not cracked, deformed or corroded.

PROCEDURE


  1. CHECK VEHICLE TYPE


    1. Check vehicle type.

      Result
      Result Proceed to
      for A25A-FKS A
      for 2GR-FKS B
      for 2AR-FE C

    B

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

    C

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

    A

  2. CHECK FOR OPEN IN CAN BUS LINES (ECM MAIN LINE)


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

    2. Disconnect the A24 ECM connector.

    3. B006ZD6C04
      *a

      Front view of wire harness connector

      (to ECM)

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A24-8 (CANH) - A24-18 (CANL) Cable disconnected from negative (-) battery terminal 108 to 132 Ω
      Result
      Result
      OK
      NG

    NG

    REPAIR OR REPLACE CAN MAIN BUS LINES OR CONNECTOR (ECM)

    OK

  3. CHECK ECM POWER SOURCE CIRCUIT


    1. Check the ECM power source circuit.

      Click here

      Result
      Result
      OK
      NG

    OK

    REPLACE ECM Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (POWER SOURCE CIRCUIT)

  4. CHECK FOR OPEN IN CAN BUS LINES (ECM MAIN LINE)


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

    2. Disconnect the A23 ECM connector.

    3. B006YC7C05
      *a

      Front view of wire harness connector

      (to ECM)

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A23-13 (CANH) - A23-26 (CANL) Cable disconnected from negative (-) battery terminal 108 to 132 Ω
      Result
      Result
      OK
      NG

    NG

    REPAIR OR REPLACE CAN MAIN BUS LINES OR CONNECTOR (ECM)

    OK

  5. CHECK ECM POWER SOURCE CIRCUIT


    1. Check the ECM power source circuit.

      Click here

      Result
      Result
      OK
      NG

    OK

    REPLACE ECM Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (POWER SOURCE CIRCUIT)

  6. CHECK FOR OPEN IN CAN BUS LINES (ECM MAIN LINE)


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

    2. Disconnect the A22 ECM connector.

    3. B006YC7C06
      *a

      Front view of wire harness connector

      (to ECM)

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A22-13 (CANH) - A22-26 (CANL) Cable disconnected from negative (-) battery terminal 108 to 132 Ω
      Result
      Result
      OK
      NG

    NG

    REPAIR OR REPLACE CAN MAIN BUS LINES OR CONNECTOR (ECM)

    OK

  7. CHECK ECM POWER SOURCE CIRCUIT


    1. Check the ECM power source circuit.

      Click here

      Result
      Result
      OK
      NG

    OK

    REPLACE ECM Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (POWER SOURCE CIRCUIT)