CAN COMMUNICATION SYSTEM, Diagnostic DTC:U0101

DTC Code DTC Name
U0101 Lost Communication with TCM

DESCRIPTION

DTC No. DTC Detection Condition Trouble Area
U0101 No communication from the TCM continues.

  • TCM branch wire or connector

  • Power source circuit of TCM

  • TCM

WIRING DIAGRAM

A005L1EE02
*a NO. 1 JUNCTION CONNECTOR
*b from MAIN Fuse
*c ECU-B NO. 2
*d from IG2 Relay

CAUTION / NOTICE / HINT

Note


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

  • Turn the ignition switch off before measuring the resistances between CAN bus main wires and between CAN bus branch wires.

  • Turn the ignition switch off before inspecting CAN bus wires for a ground short.

  • After the ignition switch is turned off, check that the key reminder warning system are not operating.

  • Before measuring the resistance, leave the vehicle as is for at least 1 minute and do not operate the ignition switch, any other switches or the doors. If any doors need to be opened in order to check connectors, open the doors and leave them open.

Tech Tips


  • Operating the ignition switch, any other switches or a door triggers related ECU and sensor communication on the CAN. This communication will cause the resistance value to change.

  • Even after DTCs are cleared, if a DTC is stored again after driving the vehicle for a while, the malfunction may be occurring due to vibration of the vehicle. In such a case, wiggling the ECUs or wire harness while performing the inspection below may help determine the cause of the malfunction.

PROCEDURE


  1. CHECK FOR OPEN IN CAN BUS WIRE (TCM BRANCH WIRE)


    1. Turn the ignition switch off.

    2. A005JNCE02
      Text in Illustration
      *a

      Front view of wire harness connector

      (to TCM)

      Disconnect the A47 TCM connector.

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

      Standard Resistance
      Tester Connection Switch Condition Specified Condition
      A47-1 (CAN+) - A47-2 (CAN-) Ignition switch off 54 to 69 Ω

    NG

    REPAIR OR REPLACE CAN BUS BRANCH WIRE OR CONNECTOR (TCM BRANCH WIRE)

    OK

  2. CHECK HARNESS AND CONNECTOR (POWER SOURCE CIRCUIT)

    A005MIYE01
    Text in Illustration
    *a

    Front view of wire harness connector

    (to TCM)

    1. Disconnect the F68 TCM connector.

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

      Standard Voltage
      Tester Connection Switch Condition Specified Condition
      F68-1 (+B) - Body ground Always 11 to 14 V
      F68-3 (IG) - Body ground Ignition switch ON 11 to 14 V

    3. 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

    REPLACE TCM (See page MULTI-MODE MANUAL TRANSAXLE (EC65A) > MULTI-MODE MANUAL TRANSAXLE ECU > REMOVAL)

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (POWER SOURCE CIRCUIT)