SFI SYSTEM, Diagnostic DTC:U0101

DTC Code DTC Name
U0101 Lost Communication with TCM

DESCRIPTION

The Transmission Control Module (TCM) and ECM perform 2-way communications with each other via the Controller Area Network (CAN). The TCM sends signals to the ECM concerning required engine speed, required engine torque, warning indicators in the combination meter, DTCs and other data. The ECM sends signals to the TCM concerning engine speed, opening angles of the throttle valve, temperature of intake air, temperature of engine coolant, engine torques and other data. If the TCM cannot communicate with the ECM, the TCM will conclude that there is a malfunction in the CAN system, illuminate the MIL and set a DTC.

DTC No. DTC Detection Condition Trouble Area
U0101

  • Following conditions are met for 1.25 seconds

  • (1 trip detection logic):


    1. Engine switch on (IG)

    2. Battery voltage 10.5 V or more

    3. No intercommunication between ECM and TCM

  • ECM to TCM circuit

  • TCM

  • ECM

WIRING DIAGRAM

A019O74E13

INSPECTION PROCEDURE

Note

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

PROCEDURE


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


    1. Connect the intelligent tester to the DLC3.

    2. Turn the engine switch on (IG).

    3. Turn the tester on.

    4. Enter the following menus: Powertrain / Engine / DTC.

    5. Read the DTCs.

      Result
      Result Proceed to
      DTC U0101 is output A
      DTC U0101 and other DTCs are output B

      Tech Tips

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


    B

    GO TO DTC CHART Click here

    A

  2. INSPECT ECU POWER SOURCE CIRCUIT (TCM POWER SOURCE)


    1. A019JVVE09
      Text in Illustration
      *a

      Front view of wire harness connector

      (to TCM)

      Disconnect the TCM 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
      D2-1 (BATT) - D2-8 (E1) Always 11 to 14 V
      D2-18 (+B) - D2-8 (E1) Engine switch on (IG) 11 to 14 V

    4. Reconnect the TCM connector.


    NG

    GO TO TCM POWER SOURCE CIRCUIT Click here

    OK

  3. CHECK HARNESS AND CONNECTOR (ECM - TCM)


    1. Disconnect the TCM connector.

    2. Disconnect the ECM connector.

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

      Standard Resistance (Check for Open)
      Tester Connection Condition Specified Condition
      D2-6 (CAN+) - D44-24 (CAN+) Always Below 1 Ω
      D2-7 (CAN-) - D44-1 (CAN-) Always Below 1 Ω
      Standard Resistance (Check for Short)
      Tester Connection Condition Specified Condition
      D2-6 (CAN+) or D44-24 (CAN+) - Body ground Always 10 kΩ or higher
      D2-7 (CAN-) or D44-1 (CAN-) - Body ground Always 10 kΩ or higher

    4. Reconnect the ECM connector.

    5. Reconnect the TCM connector.


    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (ECM - TCM)

    OK

  4. REPLACE TCM


    1. Replace the TCM Click here.


    NEXT

  5. CHECK WHETHER DTC OUTPUT RECURS (DTC U0101)


    1. Connect the intelligent tester to the DLC3.

    2. Turn the engine switch on (IG).

    3. Turn the tester on.

    4. Enter the following menus: Powertrain / Engine / DTC.

    5. Read the DTCs.

      Result
      Result Proceed to
      DTC is not output A
      DTC U0101 is output B

    B

    REPLACE ECM Click here

    A

    END