SFI SYSTEM, Diagnostic DTC:U0101

DTC Code DTC Name
U0101 Lost Communication With TCM

DESCRIPTION

The Engine Control Module (ECM) communicates with the Transmission Control Module (TCM) through the Controller Area Network (CAN).

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

DTC No.

Detection Item

DTC Detection Condition

Trouble Area

MIL

Memory

U0101

Lost Communication With TCM

All of the following conditions are met for 0.49 seconds (1 trip detection logic):

  • Ignition switch ON

  • Battery voltage 10 V or higher

  • No communication between ECM and TCM

  • TCM

  • CAN communication system

  • ECM

Comes on

DTC stored (for MMT models)

- (for M/T models)

WIRING DIAGRAM

A327735E01

CONFIRMATION DRIVING PATTERN

DTC U0101 is detected when the ignition switch is ON and wait for 2 seconds.

CAUTION / NOTICE / HINT

Note:

  • After replacing the ECM, perform idle learning.

    Click here

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

Tip:

  • If the CAN communication malfunctions, there is no data output from the ECM. In this case, some of the freeze frame data are not correct and not identical with the ECM data, however the ECM data are correct.

  • Read freeze frame data using the GTS. Freeze frame data records the engine condition when malfunctions are detected. When troubleshooting, freeze frame data can help determine if the vehicle was moving or stationary, if the engine was warmed up or not, if the air fuel ratio was lean or rich, and other data from the time the malfunction occurred.

PROCEDURE

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

    1. Connect the GTS to the DLC3.

    2. Turn the ignition switch to ON.

    3. Turn the GTS on.

    4. Enter the following menus: System Select / Health Check.

    5. Read the DTCs.

      Result

      Result

      Proceed to

      DTC U0101 is output

      A

      DTC U0101 and other DTCs are output

      B
      Tip:

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

    B

    GO TO DTC CHART

    A

  2. CHECK TERMINAL VOLTAGE (POWER SOURCE OF TCM)

    1. Disconnect the TCM connector.

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

      Standard Voltage

      Tester Connection

      Condition

      Specified Condition

      A26-1 (+B) - A26-6 (GND)

      Always

      11 to 14 V

    Result

    Proceed to

    OK

    NG
    NG

    GO TO MULTI-MODE MANUAL TRANSAXLE SYSTEM

    Click here

    OK

  3. CHECK HARNESS AND CONNECTOR (TCM - ECM)

    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

      Tester Connection

      Condition

      Specified Condition

      A27-1 (CAN+) - A34-13 (CANP)

      Always

      Below 1 Ω

      A27-2 (CAN-) - A34-12 (CANN)

      Always

      Below 1 Ω

      A27-1 (CAN+) or A34-13 (CANP) - Body ground

      Always

      10 kΩ or higher

      A27-2 (CAN-) or A34-12 (CANN) - 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

    Result

    Proceed to

    NEXT
    NEXT

  5. CHECK WHETHER DTC OUTPUT RECURS (DTC U0101)

    1. Connect the GTS to the DLC3.

    2. Turn the ignition switch to ON.

    3. Turn the GTS on.

    4. Clear the DTCs.

      Powertrain > Engine and ECT > Clear DTCs

    5. Turn the ignition switch off and wait for at least 30 seconds.

    6. Turn the ignition switch to ON and turn the GTS on.

    7. Enter the following menus: Powertrain / Engine and ECT / Trouble Codes.

    8. Read the DTCs.

      Powertrain > Engine and ECT > Trouble Codes

      Result

      Result

      Proceed to

      DTCs are not output

      A

      DTC U0101 is output

      B
    A

    END

    B

    REPLACE ECM

    Click hereClick here