Dtc U0101 Lost Communication With Tcm


DESCRIPTION

WIRING DIAGRAM

INSPECTION PROCEDURE

CHECK FOR ANY OTHER DTCS OUTPUT (IN ADDITION TO DTC U0101)

INSPECT TCM POWER SOURCE CIRCUIT (POWER SOURCE AND BODY GROUND)

CHECK HARNESS AND CONNECTOR (ECM - TCM)

REPLACE ECM

CHECK WHETHER DTC OUTPUT RECURS (DTC U0101)

DTC U0101 Lost Communication with TCM


DESCRIPTION

The ECM (engine control unit) communicates with the TCM (transmission control ECU) through the Controller Area Network (CAN).
If there is a problem with this communication, the ECM stores a DTC.

DTC Detection Drive Pattern
DTC Detection Condition
Trouble Area
Ignition switch ON for 3 seconds
Both conditions are met for 1.25 seconds (1 trip detection logic):
  1. The battery voltage is 10.5 V or higher.
  2. No communication between the ECM and TCM.
  1. ECM
  2. TCM
  3. ECM to TCM circuit

WIRING DIAGRAM


Land Cruiser, Land Cruiser Prado. Grj150 Trj150,155 Kdj150,155 Lj150, Gdj150,155.1Kd-Ftv Engine Control.Ecd System. Dtc U0101 Lost Communication With Tcm


INSPECTION PROCEDURE

1.CHECK FOR ANY OTHER DTCS OUTPUT (IN ADDITION TO DTC U0101)

  1. Connect the intelligent tester to the DLC3.

  1. Turn the ignition switch to ON and turn the tester on.

  1. Enter the following menus: Powertrain / Engine and ECT / DTC.

  1. Read the DTCs.

    Result
    Result
    		Proceed to
    DTC U0101 is output
    		A
    DTC U0101 and other DTCs are output
    		B
    HINT:
    If any DTCs other than U0101 are output, troubleshoot those DTCs first.


B
GO TO DTC CHART (LandCruiser RM0000031HW07LX.html)
A


2.INSPECT TCM POWER SOURCE CIRCUIT (POWER SOURCE AND BODY GROUND)


    Land Cruiser, Land Cruiser Prado. Grj150 Trj150,155 Kdj150,155 Lj150, Gdj150,155.1Kd-Ftv Engine Control.Ecd System. Dtc U0101 Lost Communication With Tcm

  1. Disconnect the TCM connector.

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

    Standard Voltage:
    Tester Connection
    		Switch Condition
    		Specified Condition
    G70-5 (BATT) - G69-1 (E1)
    		Ignition switch ON
    		11 to 14 V
    Text in Illustration
    *a
    		Rear view of wire harness connector
    (to TCM)

  1. Reconnect the TCM connector.



NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK


3.CHECK HARNESS AND CONNECTOR (ECM - TCM)

  1. Disconnect the TCM connector.

  1. Disconnect the ECM connector.

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

    Standard Resistance:
    Tester Connection
    		Condition
    		Specified Condition
    C92-24 (CAN+) - G70-21 (CAN+)
    		Always
    		Below 1 Ω
    C92-18 (CAN-) - G70-20 (CAN-)
    		Always
    		Below 1 Ω
    C92-24 (CAN+) or G70-21 (CAN+) - Body ground or other terminals
    		Always
    		1 MΩ or higher
    C92-18 (CAN-) or G70-20 (CAN-) - Body ground or other terminals
    		Always
    		1 MΩ or higher

  1. Reconnect the TCM connector.

  1. Reconnect the ECM connector.



NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK


4.REPLACE ECM

  1. Replace the ECM (LandCruiser RM0000013Z002CX.html).


NEXT


5.CHECK WHETHER DTC OUTPUT RECURS (DTC U0101)

  1. Connect the intelligent tester to the DLC3.

  1. Turn the ignition switch to ON and turn the tester on.

  1. Enter the following menus: Powertrain / Engine and ECT / DTC.

  1. Read the DTCs.

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


B
REPLACE TCM (LandCruiser RM0000048F300JX.html)
A

END