CAN COMMUNICATION SYSTEM(w/ Toyota Safety Sense) ECM Communication Stop Mode

DESCRIPTION

Detection Item Symptom Trouble Area
ECM Communication Stop Mode

Either condition is met:


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

    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


  • Power source or inside ECM

  • ECM main wire or connector

  • ECM

WIRING DIAGRAM

A0048FOE03
A004A3AE03
A0049MRE09
A0049MRE10

CAUTION / NOTICE / HINT

Note


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

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

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

  • After the ignition switch is turned off, check that the key 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 ignition 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 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 MAIN WIRE (ECM MAIN WIRE)


    1. Disconnect the ECM connector.

    2. A004B5BE01
      Text in Illustration
      *A for 1NR-FE
      *B for 1KR-FE
      *C for 1ND-TV with DPF
      *D for 1ND-TV without DPF
      *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 Switch Condition Specified Condition

      A58-13 (CANH) - A58-26 (CANL)*1

      A93-26 (CANH) - A93-25 (CANL)*2

      A108-26 (CANH) - A108-25 (CANL)*3

      A59-3 (CANH) - A59-4 (CANL)*4

      		 Ignition switch off 108 to 132 Ω

      *1: for 1NR-FE

      *2: for 1KR-FE

      *3: for 1ND-TV with DPF

      *4: for 1ND-TV without DPF


    NG

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

    OK

  2. CHECK HARNESS AND CONNECTOR (POWER SOURCE CIRCUIT)


    1. Check for the ECM power source circuit (for 1NR-FE) Click here.

    2. Check for the ECM power source circuit (for 1KR-FE) Click here.

    3. Check for the ECM power source circuit (for 1ND-TV with DPF) Click here.

    4. Check for the ECM power source circuit (for 1ND-TV without DPF) Click here

      Result
      Result Proceed to
      OK (for 1NR-FE) A
      OK (for 1KR-FE) B
      OK (for 1ND-TV with DPF) C
      OK (for 1ND-TV without DPF) D
      NG E

    A

    REPLACE ECM Click here

    B

    REPLACE ECM Click here

    C

    REPLACE ECM Click here

    D

    REPLACE ECM Click here

    E

    REPAIR OR REPLACE HARNESS OR CONNECTOR