AUTOMATIC TRANSMISSION SYSTEM, Diagnostic DTC:U0100

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

DESCRIPTION

The engine control unit intercommunicates with the TCM using the Controller Area Network (CAN).

If there is a problem in this intercommunication, the TCM stores the DTC.

DTC No. DTC Detection Condition Trouble Area
U0100

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


  • Engine switch is on (IG)

  • Battery voltage is 10.5 V or higher

  • No intercommunication between the ECM and TCM


  • Harness and connector

  • ECM

  • TCM

WIRING DIAGRAM

A01GL5SE07

INSPECTION PROCEDURE

Tech Tips


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

PROCEDURE


  1. CHECK DTC OUTPUT (IN ADDITION TO DTC U0100)


    1. Connect the intelligent tester to the DLC3.

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

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

    4. Read the DTCs using the intelligent tester.

      Result
      Display (DTC output) Proceed to
      Only U0100 is output A
      U0100 and other DTCs are output B

    B
    A
  2. INSPECT TCM (POWER SOURCE, GROUND)


    1. A01GK3QE12

      Disconnect the A12 and E5 TCM connectors.

    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
      A12-6 (+B) - E5-7 (E1) Engine switch on (IG) 11 to 14 V
    4. Turn the engine switch off.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      E5-7 (E1) - Body ground Always Below 1 Ω

    NG
    OK
  3. CHECK HARNESS AND CONNECTOR (ECM - TCM)


    1. A01GNT6E02

      Disconnect the A13 ECM connector.

    2. Disconnect the A12 TCM connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A13-10 (CAN+) - A12-18 (CAN+) Always Below 1 Ω
      A13-9 (CAN-) - A12-28 (CAN-) Always Below 1 Ω
      A13-10 (CAN+) or A12-18 (CAN+) - Body ground Always 10 kΩ or higher
      A13-9 (CAN-) or A12-28 (CAN-) - Body ground Always 10 kΩ or higher

    NG
    OK
  4. CHECK IF DTC RECURS


    1. Clear the DTC Click here.

    2. Replace the TCM Click here.

      Tech Tips

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

    3. Start the engine.

    4. Read the DTCs.

      Result
      Display (DTC output) Proceed to
      No DTC A
      U0100 is output B

    B
    A
  5. REPLACE TCM


    1. Replace the TCM Click here.


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