MULTI-MODE MANUAL TRANSAXLE SYSTEM, Diagnostic DTC:U0100

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

DESCRIPTION

The transmission control ECU and ECM communicate with each other via the CAN communication line.

DTC No. DTC Detection Conditions Trouble Areas
U0100

No communication with the ECM

(1 trip detection logic)

  • Open or short in CAN signal circuit

  • ECM

  • Transmission control ECU

  • CAN communication system components

WIRING DIAGRAM

A01379SE01

INSPECTION PROCEDURE

Tech Tips

If the CAN communication malfunctions, the transmission control ECU cannot receive the current data from the ECM. In this case, the freeze frame data output from the transmission control ECU have not been updated so that 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 Conditions 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 to OFF.

  3. Connect the intelligent tester to the DLC3.

  4. Turn the ignition switch to ON and turn the tester ON.

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

Items

[Abbreviation]

 Measurement Items: Display Normal Conditions Diagnostic Notes

Calculated Engine Load

[Calc E/G Load]

Calculated load by ECM:

Min.: 0 %, Max.: 100 %

1.5 to 3.0 %: Idling

2.0 to 10.0 %: Running without load (2,500 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.: 8,160 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

Note

In ECM replacement, perform the electronic throttle learning after installing the ECM.

PROCEDURE


  1. CHECK DTC OUTPUT


    1. Connect the intelligent tester to the DLC3.

    2. Turn the ignition switch to ON and turn the tester ON.

    3. Select the following menu items: Powertrain / Multi-Mode M/T / DTC.

    4. Read DTCs.

      Result
      Display (DTC Output) Proceed To
      U0100 (w/o VSC System) A
      U0100 (w/ VSC System) B
      DTC not output C

    B

    INSPECT CAN COMMUNICATION SYSTEM

    C

    CHECK FOR INTERMITTENT PROBLEMS

    A

  2. CHECK HARNESS AND CONNECTOR (TRANSMISSION CONTROL ECU - ECM)

    A0138PKE01

    1. Disconnect the ECM connector.

    2. Disconnect the transmission control ECU connector.

    3. Check the resistance.

      Standard Resistance
      Tester Connections Specified Conditions
      CAN+ (A28-1) - CAN+ (B25-64) Below 1 Ω
      CAN- (A28-2) - CAN- (B25-45) Below 1 Ω
      CAN+ (A28-1) - Body ground 10 kΩ or higher
      CAN- (A28-2) - Body ground 10 kΩ or higher

    4. Reconnect the ECM connector.

    5. Reconnect the transmission control ECU connector.


    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  3. REPLACE TRANSMISSION CONTROL ECU ASSEMBLY


    1. Replace the transmission control ECU.

      CAUTION:

      Replace the transmission control ECU with a transmission control ECU from a normally functioning vehicle of the same model.


    NEXT

  4. CHECK DTC OUTPUT


    1. Connect the intelligent tester to the DLC3.

    2. Turn the ignition switch to ON and turn the tester ON.

    3. Clear the DTC.

    4. Turn the ignition switch to OFF and turn the tester OFF.

    5. Start the engine and turn the tester ON.

    6. Select the following menu items: Powertrain / Multi-Mode M/T / DTC.

    7. Read DTCs.

      Result
      Display (DTC Output) Proceed To
      U0100 A
      DTC not output B

    B

    REPLACE TRANSMISSION CONTROL ECU ASSEMBLY

    A

    REPLACE ECM