Dtc U0101 Lost Communication With Tcm

Engine. Camry. Acv40 Gsv40
2Gr-Fe Engine Control System. Camry. Acv40 Gsv40

DESCRIPTION

WIRING DIAGRAM

INSPECTION PROCEDURE

CHECK OTHER DTC OUTPUT (IN ADDITION TO DTC U0101)

CHECK TCM (+B AND E1 TERMINALS)

CHECK HARNESS AND CONNECTOR

REPLACE ECM

CHECK IF DTC RECURS

DTC U0101 Lost Communication with TCM


DESCRIPTION

The Transmission Control Module (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 and set a DTC.

DTC No.
DTC Detection Condition
Trouble Area
U0101
No communication from TCM continues
  1. Open or short in TCM and ECM circuit
  2. TCM
  3. ECM

WIRING DIAGRAM


Camry. Acv40 Gsv40.2Gr-Fe Engine Control System.Sfi System. Dtc U0101 Lost Communication With Tcm


INSPECTION PROCEDURE

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

  1. Connect the intelligent tester to the DLC3.

  1. Turn the ignition switch to the ON position.

  1. Turn the tester on.

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

  1. Read the DTCs.

    Result:

    Display (DTC output)
    		Proceed to
    U0101
    		A
    U0101 and other DTCs
    		B


B
GO TO DTC CHART (CAMRY_ACV40 RM000002DSC01VX.html)
A


2.CHECK TCM (+B AND E1 TERMINALS)


    Camry. Acv40 Gsv40.2Gr-Fe Engine Control System.Sfi System. Dtc U0101 Lost Communication With Tcm

  1. Disconnect the TCM connector.

  1. Turn the ignition switch to the ON position.

  1. Measure the voltage of the TCM connector.

    Standard voltage:
    Tester Connection
    		Specified Condition
    C56-18 (+B) - C56-8 (E1)
    		9 to 14 V

  1. Turn the ignition switch off.

  1. Measure the resistance of the TCM connector.

    Standard resistance:
    Tester Connection
    		Specified Condition
    C56-8 (E1) - Body ground
    		Below 1 Ω


NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK


3.CHECK HARNESS AND CONNECTOR


    Camry. Acv40 Gsv40.2Gr-Fe Engine Control System.Sfi System. Dtc U0101 Lost Communication With Tcm

  1. Disconnect the C56 TCM connector.

  1. Disconnect the C58 (RHD) or C55 (LHD) ECM connector.

  1. Measure the resistance of the wire harness side connectors.

    Standard resistance:
    RHD:
    Tester Connection
    		Specified Condition
    CAN+ (C56-6) - CAN+ (C58-2)
    		Below 1 Ω
    CAN- (C56-7) - CAN- (C58-1)
    		Below 1 Ω
    CAN+ (C56-6) or CAN+ (C58-2) - Body ground
    		1 MΩ or higher
    CAN- (C56-7) or CAN- (C58-1) - Body ground
    		1 MΩ or higher
    LHD:
    Tester Connection
    		Specified Condition
    CAN+ (C56-6) - CAN+ (C55-2)
    		Below 1 Ω
    CAN- (C56-7) - CAN- (C55-1)
    		Below 1 Ω
    CAN+ (C56-6) or CAN+ (C55-2) - Body ground
    		1 MΩ or higher
    CAN- (C56-7) or CAN- (C55-1) - Body ground
    		1 MΩ or higher


NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK


4.REPLACE ECM

  1. Replace the ECM (CAMRY_ACV40 RM0000022NT01EX.html).

    CAUTION:
    Replace the ECM with the ECM of normally functioning vehicle of the same model.

NEXT


5.CHECK IF DTC RECURS

  1. Connect the intelligent tester to the DLC3.

  1. Clear the DTC.

  1. Start the engine.

  1. Read the DTCs.

    Result:

    Display (DTC Output)
    		Proceed to
    U0101
    		A
    No DTC
    		B


B
REPLACE ECM (CAMRY_ACV40 RM0000022NT01EX.html)
A

REPLACE TCM (CAMRY_ACV40 RM000002DAK026X.html)