ECD SYSTEM(for CCo), Diagnostic DTC:U0101

DTC Code DTC Name
U0101 Lost Communication with TCM

DESCRIPTION

The ECM (engine control unit) communicates with the TCM (transmission control ECU) through the Controller Area Network (CAN).

If there is a problem with this communication, the ECM stores a DTC.

DTC No.

Detection Item

DTC Detection Condition

Trouble Area

MIL

Memory

U0101

Lost Communication with TCM

The following conditions are met for 1.25 seconds (1 trip detection logic):

  • The battery voltage is 10.5 V or higher.

  • No communication between the ECM and TCM.

  • ECM

  • TCM

  • ECM to TCM circuit

Comes on

DTC stored

CONFIRMATION DRIVING PATTERN

DTC No.

DTC Detection Drive Pattern

U0101

Ignition switch ON for 3 seconds

WIRING DIAGRAM

C206826E07

CAUTION / NOTICE / HINT

Note:

After replacing the ECM, the new ECM needs registration (Click here) and initialization (Click here).

PROCEDURE

  1. CHECK OTHER DTC OUTPUT (IN ADDITION TO DTC U0101)

    1. Connect the GTS to the DLC3.

    2. Turn the ignition switch to ON and turn the GTS

    3. Enter the following menus: Powertrain / Engine / Trouble Codes.

      Powertrain > Engine > Trouble Codes

    4. Read the DTCs.

      Result

      Proceed to

      DTC U0101 is output

      DTC U0101 and other DTCs are output
      Tip:

      If any DTCs other than U0101 are output, troubleshoot those DTCs first.

    DTC U0101 and other DTCs are output

    GO TO DTC CHART

    Click hereClick here

    DTC U0101 is output

  2. CHECK TERMINAL VOLTAGE (POWER SOURCE OF TCM)

    1. C205632C07

      *1

      Front view of wire harness connector

      (to TCM)

      Disconnect the TCM connector.

    2. Turn the ignition switch to ON.

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

      Standard Voltage

      Tester Connection

      Condition

      Specified Condition

      B79-18 (+B) - B79-8 (E1)

      Ignition switch ON

      11 to 14 V

    Result

    Proceed to

    OK

    NG
    NG

    REPAIR OR REPLACE HARNESS OR CONNECTORClick here

    OK

  3. CHECK HARNESS AND CONNECTOR (ECM - TCM)

    1. C206298C01

      *1

      Front view of wire harness connector

      (to ECM)

      *2

      Front view of wire harness connector

      (to TCM)

      Disconnect the TCM connector.

    2. Disconnect the ECM connector.

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

      Standard Resistance

      Tester Connection

      Condition

      Specified Condition

      B76-40 (CAN+) - B79-6 (CAN+)

      Always

      Below 1 Ω

      B76-63 (CAN-) - B79-7 (CAN-)

      Always

      Below 1 Ω

      B76-40 (CAN+) or B79-6 (CAN+) - Body ground

      Always

      10 kΩ or higher

      B76-63 (CAN-) or B79-7 (CAN-) - Body ground

      Always

      10 kΩ or higher

    Result

    Proceed to

    OK

    NG
    NG

    REPAIR OR REPLACE HARNESS OR CONNECTORClick here

    OK

  4. REPLACE ECM

    1. Replace the ECM.

      Click here

    Result

    Proceed to

    NEXT
    NEXT

  5. CHECK WHETHER DTC OUTPUT RECURS (IN ADDITION TO DTC U0101)

    1. Connect the GTS to the DLC3.

    2. Turn the ignition switch to ON and turn the GTS

    3. Enter the following menus: Powertrain / Engine / Trouble Codes.

      Powertrain > Engine > Trouble Codes

    4. Read the DTCs.

      Result

      Proceed to

      DTC is not output

      DTC U0101 is output
    DTC is not output

    END

    DTC U0101 is output

  6. REPLACE TCM

    1. Replace the TCM.

      Click here

    Result

    Proceed to

    NEXT
    NEXT

    CONFIRM WHETHER MALFUNCTION HAS BEEN SUCCESSFULLY REPAIREDClick here

  7. REPAIR OR REPLACE HARNESS OR CONNECTOR

    1. Repair or replace the harness or connector.

    Result

    Proceed to

    NEXT
    NEXT

  8. CONFIRM WHETHER MALFUNCTION HAS BEEN SUCCESSFULLY REPAIRED

    1. Connect the GTS to the DLC3.

    2. Turn the ignition switch to ON and turn the GTS

    3. Enter the following menus: Powertrain / Engine / Trouble Codes.

      Powertrain > Engine > Trouble Codes

    4. Confirm that the DTC is not output again.

    Result

    Proceed to

    NEXT
    NEXT

    END