AUTOMATIC TRANSAXLE SYSTEM, Diagnostic DTC:U0100

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

DESCRIPTION

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

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

DTC Code DTC Detection Condition Trouble Area
U0100

All conditions are met for 1.25 seconds (1-trip detection logic):


  • Ignition switch is ON

  • Battery voltage is 10.5 V or higher

  • No communication between the ECM and TCM

  • Harness and connector

  • ECM

  • TCM

WIRING DIAGRAM

A00OT87E01

INSPECTION PROCEDURE

Tech Tips


  • Refer to the inspection procedure for the CAN communication system.

  • If the CAN communication malfunctions, the TCM cannot receive current data from the ECM. In this case, the freeze frame data output from the TCM has not been 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 confirmed using the Bus Check function of the intelligent tester Click here.

PROCEDURE


  1. CHECK TCM (POWER SOURCE, BODY GROUND)


    1. A00OVTQE04
      Text in Illustration
      *1

      Front view of wire harness connector

      (to TCM)

      Disconnect the TCM connector.

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

      Standard Voltage
      Tester Connection Switch Condition Specified Condition
      B77-18 (+B) - Body ground Ignition switch ON 11 to 14 V

    3. Turn the ignition switch off.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      B77-8 (E1) - Body ground Always Below 1 Ω

    NG

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

    OK

  2. CHECK HARNESS AND CONNECTOR (ECM - TCM)


    1. Disconnect the ECM connector.

    2. Disconnect the TCM connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      B39-40 (CAN+) - B77-6 (CAN+) Always Below 1 Ω
      B39-63 (CAN-) - B77-7 (CAN-) Always Below 1 Ω
      B39-40 (CAN+) or B77-6 (CAN+) - Body ground or other terminals Always 10 kΩ or higher
      B39-63 (CAN-) or B77-7 (CAN-) - Body ground or other terminals Always 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  3. CHECK IF DTC OUTPUT RECURS (DTC U0100)


    1. Connect the intelligent tester to the DLC3.

    2. Turn the ignition switch to ON.

    3. Turn the intelligent tester on.

    4. Enter the following menus: Powertrain / ECT / DTC / Clear.

    5. Replace the TCM Click here.

      Tech Tips

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

    6. Start the engine.

    7. Enter the following menus: Powertrain / ECT / DTC.

    8. Read the DTCs using the intelligent tester.

      Result
      Result Proceed to
      U0100 is output A
      DTCs are not output B

    B

    REPLACE TCM Click here

    A

    REPLACE ECM Click here