AUTOMATIC TRANSMISSION SYSTEM(for 2GR-FSE), Diagnostic DTC:U0100

DTC Code DTC Name
U0100 Lost Communication with ECM / PCM "A"

DESCRIPTION

The ECM communicates with the TCM via the Controller Area Network (CAN).

If there is a problem in communication, the TCM stores this DTC.

DTC No. Detection Item DTC Detection Condition Trouble Area MIL Memory
U0100 Lost Communication with ECM / PCM "A"

1. Diagnosis Condition 2. Malfunction Status 3. Malfunction Time 4. Other


  1. The engine switch is on (IG) and battery voltage is 10.5 V or more.

  2. There is no communication between the ECM and TCM.

  3. 1.25 seconds or more

  4. 1-trip detection logic

  • Harness and connector

  • ECM

  • TCM

 Comes on DTC stored

WIRING DIAGRAM

A01VTBIE03
*a from EFI-MAIN Relay
*b CAN Communication Line

CAUTION / NOTICE / HINT

Note


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

  • Perform registration and/or initialization when parts related to the automatic transmission are replaced.

    Click here

Tech Tips


  • If the CAN communication system malfunctions, the TCM cannot receive current data from the ECM. In this case, the freeze frame data output from the TCM is not updated, so the data will not be useful for the inspection. However, reading the Data List as the first step in troubleshooting is an effective way to find malfunctions.

  • The malfunctioning area can be checked using the CAN Bus Check function on the GTS.

  • After the repair, clear the DTCs and perform the following procedure to check that DTCs are not output.


    1. Check the battery voltage is 10.5 V or more.

    2. Turn the engine switch on (IG).

    3. Check for DTCs again.

      Click here

PROCEDURE


  1. CHECK TERMINAL VOLTAGE (POWER SOURCE OF ECM)


    1. A01VS9OC11
      *a

      Rear view of wire harness connector

      (to ECM)

      Disconnect the A71 ECM connector.

    2. Turn the engine switch on (IG).

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      A71-1 (+B2) - Body ground Engine switch on (IG) 11 to 14 V
      A71-2 (+B) - Body ground Engine switch on (IG) 11 to 14 V
      Result
      Proceed to
      OK
      NG

    NG

    GO TO ECM POWER SOURCE CIRCUIT (ENGINE CONTROL SYSTEM / SFI SYSTEM) w/o Canister Pump Module: Click here
    GO TO ECM POWER SOURCE CIRCUIT (ENGINE CONTROL SYSTEM / SFI SYSTEM) w/ Canister Pump Module: Click here

    OK

  2. CHECK HARNESS AND CONNECTOR (ECM - BODY GROUND)


    1. Disconnect the F4 ECM connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      F4-1 (E1) - Body ground Always Below 1 Ω
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (ECM - BODY GROUND)

    OK

  3. CHECK HARNESS AND CONNECTOR (ECM - TCM)


    1. Disconnect the A71 ECM connector.

    2. Disconnect the A37 TCM connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A71-10 (CAN+) - A37-21 (CAN+) Always Below 1 Ω
      A71-9 (CAN-) - A37-13 (CAN-) Always Below 1 Ω
      A71-10 (CAN+) or A37-21 (CAN+) - Body ground Always 10 kΩ or higher
      A71-9 (CAN-) or A37-13 (CAN-) - Body ground Always 10 kΩ or higher
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  4. REPLACE TCM


    1. Replace the TCM.

      Click here

      Tech Tips

      Replace the TCM with a TCM of a normally functioning vehicle of the same model.

      Result
      Proceed to
      NEXT

    NEXT

  5. CHECK DTC OUTPUT


    1. Clear the DTCs.


      Powertrain > ECT > Clear DTCs

    2. Start the engine.

    3. Read the DTCs.


      Powertrain > ECT > Trouble Codes
      Result
      Result Proceed to
      DTCs are not output A
      DTC U0100 is output B

    A

    PERFORM A/T CODE REGISTRATION Click here

    B

  6. REPLACE ECM


    1. Replace the ECM.

      Click here

      Result
      Proceed to
      NEXT

    NEXT

    PERFORM RESET MEMORY Click here