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 communications 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, illuminate the multi-mode manual transmission warning light and set a DTC.

DTC No. DTC Detection Condition Trouble Area
U0100

No communication with the ECM

(1-trip detection logic)

  • Open or short in CAN signal circuit

  • ECM

  • TCM

WIRING DIAGRAM

A005I8VE10
*a ECU-B NO. 2
*b MAIN
*c BATTERY

CAUTION / NOTICE / HINT

Tech Tips

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

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.

To check the Data List, perform the following procedure using the intelligent tester.


  1. Warm up the engine.

  2. Turn the ignition switch off.

  3. Connect the intelligent tester to the DLC3.

  4. Turn the ignition switch to ON.

  5. Turn the tester on.

  6. Following the display on the tester, read the Data List.

Tester Display Measurement Item/Range Normal Condition Diagnostic Note

Calculated Engine Load

[Calc E/G Load]

Calculated load by ECM:

Min.: 0 %, Max.: 100 %

10 to 25%: Idling

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

 -

Engine Coolant Temperature

[Coolant Temp]

Coolant temperature:

Min.: -40°C , Max.: 215°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

[Bacup Engin Spd]

Back-up engine speed:

Min.: 0 rpm, Max.: 8160 rpm

0 rpm: Vehicle stopped

Approximately same as tachometer reading: Vehicle running

 0 rpm displayed when malfunction in CAN communication

Accelerator Pedal Angle

[Accel Pedl Angl]

Accelerator pedal angle

Min.: 0%, Max.: 100%

 0%: Accelerator pedal released 0% displayed when malfunction in CAN communication

PROCEDURE


  1. CHECK TCM (+B AND GND TERMINALS)


    1. A005GPTE02
      Text In Illustration
      *a

      Front view of wire harness connector

      (to TCM)

      Disconnect the F68 TCM connector.

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

      Standard voltage
      Tester Connection Condition Specified Condition
      F68-1 (+B) - F68-6 (GND) Always 9 to 14 V

    NG

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

    OK

  2. CHECK HARNESS AND CONNECTOR (ECM - TCM)


    1. Disconnect the A47 TCM connector.

    2. Disconnect the A59 ECM connector.

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

      Standard resistance (check for open)
      Tester Connection Condition Specified Condition
      A59-3 (CANH) - A47-1 (CAN+) Always Below 1 Ω
      A59-4 (CANL) - A47-2 (CAN-) Always Below 1 Ω
      Standard resistance (check for short)
      Tester Connection Condition Specified Condition
      A59-3 (CANH) or A47-1 (CAN+) - Body ground Always 10 kΩ or higher
      A59-4 (CANL) or A47-2 (CAN-) - Body ground Always 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (ECM - TCM)

    OK

  3. REPLACE ECM


    1. Replace the ECM Click here.

      CAUTION:

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


    NEXT

  4. CHECK IF DTC RECURS


    1. Connect the intelligent tester to the DLC3.

    2. Clear the DTCs Click here.

    3. Start the engine.

    4. Read the DTCs.

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

    B

    END

    A

  5. REPLACE TCM


    1. Replace the TCM Click here.


    NEXT

  6. PERFORM INITIALIZATION


    1. Perform the initialization and learning for multi-mode manual transaxle system Click here.


    NEXT

    END

  7. CHECK HARNESS OR CONNECTOR (TCM - BODY GROUND)


    1. Disconnect the F68 TCM connector.

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

      Standard resistance
      Tester Connection Condition Specified Condition
      F68-6 (GND) - Body ground Always Below 1 Ω

    OK

    REPAIR OR REPLACE HARNESS OR CONNECTOR (TCM - BATTERY)

    NG

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