MULTI-MODE MANUAL TRANSAXLE SYSTEM, Diagnostic DTC:U0100

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

DESCRIPTION

The TCM and ECM perform 2-way communication with each other via the Controller Area Network (CAN). The TCM sends signals to the ECM concerning required engine rpm, required engine torques, warning indicators in the combination meter, DTCs and other data. The ECM sends signals to the TCM concerning engine rpm, 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 multi-mode manual transaxle warning light, and store this DTC.

DTC No.

Detection Item

DTC Detection Condition

Trouble Area

MIL

Warning Indicate

Memory

U0100

Lost Communication with ECM / PCM "A"

No communication with the ECM

(1-trip detection logic)

  • Wire harness or connector

  • ECM

  • TCM

Comes on

Comes on

DTC stored

WIRING DIAGRAM

C389365E01

CAUTION / NOTICE / HINT

Tip:

If the CAN communication malfunctions, the TCM cannot receive the current data from the ECM. In this case, the freeze frame data output from the TCM has not been updated, so it will not be useful information for the inspection procedure. However, reading the Data List as the first step of troubleshooting is effective to find malfunctions.

Note:

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

  • In the table below, the values listed under Normal Condition are for reference only. Do not depend solely on these reference values when deciding whether a part is faulty or not.

  1. DATA LIST

    1. Warm up the engine.

    2. Turn the ignition switch off.

    3. Connect the GTS to the DLC3.

    4. Turn the ignition switch to ON.

    5. Turn the GTS on.

    6. Enter the following menus: Powertrain / Multi-Mode M/T / Data List.

      Powertrain > Multi-Mode M/T > Data List

      Tester Display

      Measurement Item

      Range

      Normal Condition

      Diagnostic Note

      Calculated Engine Load

      Load calculated by ECM

      Min.: 0%, Max.: 100%

      10 to 25%: Idling

      5 to 20%: Running without load (2500 rpm)

      -

      Engine Coolant Temperature

      Coolant temperature

      Min.: -40°C, Max.: 140°C

      75 to 95°C (167 to 203°F):

      After engine warmed up

      • If value -40°C (-40°F): sensor circuit open

      • If value 140°C (284°F): sensor circuit shorted

      Backup Engine Speed

      Back-up engine speed

      Min.: 0 rpm, Max.: 8160 rpm

      0 rpm: Engine stopped

      720 to 820 rpm: Idling

      0 rpm displayed when malfunctions in CAN communication

      Accelerator Pedal Angle

      Accelerator pedal angle

      Min.: 0%, Max.: 100%

      0%: Accelerator pedal released

      0 % displayed when malfunctions in CAN communication regardless of the accelerator pedal status.

      Powertrain > Multi-Mode M/T > Data List

      Tester Display

      Calculated Engine Load

      Engine Coolant Temperature

      Backup Engine Speed

      Accelerator Pedal Angle

PROCEDURE

  1. CHECK TCM (+B AND GND TERMINALS)

    1. C239995C07

      *a

      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

      Condition

      Specified Condition

      E104-1 (+B) - E104-6 (GND)

      Always

      11 to 14 V

    Result

    Proceed to

    OK

    NG
    NG

    CHECK HARNESS AND CONNECTOR (TCM - BODY GROUND)Click here

    OK

  2. CHECK HARNESS AND CONNECTOR (TCM - ECM)

    1. Disconnect the ECM connector.

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

      Standard Resistance

      Tester Connection

      Condition

      Specified Condition

      A169-30 (CANP) - A108-1 (CAN+)

      Always

      Below 1 Ω

      A169-31 (CANN) - A108-2 (CAN-)

      Always

      Below 1 Ω

      A169-30 (CANP) or A108-1 (CAN+) - Body ground

      Always

      10 kΩ or higher

      A169-31 (CANN) or A108-2 (CAN-) - Body ground

      Always

      10 kΩ or higher

    Result

    Proceed to

    OK

    NG
    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  3. REPLACE ECM

    1. Replace the ECM.

      Click here

      CAUTION:

      Replace the ECM with a known good ECM of the same model vehicle.

    Result

    Proceed to

    NEXT
    NEXT

  4. CHECK IF DTC RECURS

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

      Powertrain > Engine and ECT > Trouble Codes

    6. Read the DTCs.

    Result

    Result

    Proceed to

    DTC U0101 is output

    A

    DTCs are not output

    B
    B

    END

    A

  5. REPLACE TCM

    1. Replace the TCM.

      Click here

    Result

    Proceed to

    NEXT
    NEXT

    PERFORM INITIALIZATION

    Click here

  6. CHECK HARNESS AND CONNECTOR (TCM - BODY GROUND)

    1. C239995C08

      *a

      Front view of wire harness connector

      (to TCM)

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

      Standard Resistance

      Tester Connection

      Condition

      Specified Condition

      E104-6 (GND) - Body ground

      Always

      Below 1 Ω

    Result

    Proceed to

    OK

    NG
    OK

    REPAIR OR REPLACE HARNESS OR CONNECTOR (TCM - BATTERY)

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR