SFI SYSTEM, Diagnostic DTC:U0101

DTC Code DTC Name
U0101 Lost Communication with TCM

DESCRIPTION

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

If there is a problem in this intercommunication, the ECM sets 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 is 10.5 V or more

    3. No intercommunication between ECM and TCM

  • ECM

  • TCM

  • ECM to TCM circuit

WIRING DIAGRAM

A015ZMFE07

INSPECTION PROCEDURE

PROCEDURE


  1. CHECK ANY OTHER DTC 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: Utility / All Codes.

    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

    A

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


    1. A0162RIE05

      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 Switch Condition Specified Condition
      A58-5 (+B) - Body ground 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 (TCM - BODY GROUND)


    1. Disconnect the TCM connector.

    2. A0162RIE06

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

      Standard Resistance
      Tester Condition Condition Specified Condition
      A58-2 (E1) - Body ground Always Below 1 Ω

    3. Reconnect the TCM connector.


    NG

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

    OK

  4. CHECK HARNESS AND CONNECTOR (ECM - TCM)


    1. A015ZWPE04

      Disconnect the ECM connector.

    2. Disconnect the TCM connector.

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

      Standard Resistance (Check for Open)
      Tester Connection Condition Specified Condition
      A6-10 (CAN+) - A58-21 (CAN+) Always Below 1 Ω
      A6-9 (CAN-) - A58-13 (CAN-) Always Below 1 Ω
      Standard Resistance (Check for Short)
      Tester Connection Condition Specified Condition
      A6-10 (CAN+) or A58-21 (CAN+) - Body ground Always 10 kΩ or higher
      A6-9 (CAN-) or A58-13 (CAN-) - Body ground Always 10 kΩ or higher

    4. Reconnect the ECM connector and TCM connector.


    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  5. REPLACE ECM


    1. Replace the ECM Click here.


    NEXT

  6. CHECK WHETHER DTC OUTPUT RECURS (DTC U0101)


    1. Connect the intelligent tester to the DLC3.

    2. Turn the engine switch on (IG) and turn the tester ON.

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

    4. Read the DTC.

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

    B

    REPLACE TCM Click here

    A

    END