Dtc U0100 Lost Communication With Ecm / Pcm A

Transmission. Camry. Acv40 Gsv40
U660E Automatic Transaxle. Camry. Acv40 Gsv40

DESCRIPTION

WIRING DIAGRAM

INSPECTION PROCEDURE

CHECK ECU TERMINAL VOLTAGE (+B AND E1 TERMINALS)

CHECK HARNESS AND CONNECTOR (TCM - ECM)

CHECK IF DTC OUTPUT RECURS

DTC U0100 Lost Communication with ECM / PCM "A"


DESCRIPTION

The engine control unit intercommunicates with the TCM with the Controller Area Network (CAN).
If there is a problem in this intercommunication, the TCM sets a DTC.

DTC No.
DTC Detection Condition
Trouble Area
U0100
  1. Following conditions are met for 1.25 seconds (1 trip detection logic):
    1. Ignition switch on
    2. Battery voltage is 10.5 V or more
    3. No intercommunication between the ECM and TCM
TCM

WIRING DIAGRAM


Camry. Acv40 Gsv40.U660E Automatic Transaxle.Automatic Transaxle System. Dtc U0100 Lost Communication With Ecm / Pcm A


INSPECTION PROCEDURE

HINT:
  1. Refer to inspection procedure for CAN communication system (CAMRY_ACV40 RM000000WI603XX.html for RHD).
  2. 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 have not been updated, so the data will not be useful for the inspection. However, reading the Data List as the first step in troubleshooting is effective to find malfunctions.
  3. The malfunction area can be checked using the BUS CHECK function on the intelligent tester (CAMRY_ACV40 RM000000WIB03ZX.htmlfor LHD, CAMRY_ACV40 RM000000WIB040X.html for RHD).
1.CHECK ECU TERMINAL VOLTAGE (+B AND E1 TERMINALS)


    Camry. Acv40 Gsv40.U660E Automatic Transaxle.Automatic Transaxle System. Dtc U0100 Lost Communication With Ecm / Pcm A

  1. Disconnect the TCM connector.

  1. Turn the ignition switch on.

  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


2.CHECK HARNESS AND CONNECTOR (TCM - ECM)


    Camry. Acv40 Gsv40.U660E Automatic Transaxle.Automatic Transaxle System. Dtc U0100 Lost Communication With Ecm / Pcm A

  1. Disconnect the C56 TCM connector.

  1. Disconnect the C58*1 or C55*2 ECM connector.
    *1: for RHD
    *2: for LHD

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

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


NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK


3.CHECK IF DTC OUTPUT RECURS

  1. Connect the intelligent tester to the DLC3.

  1. Clear the DTC.

  1. Replace the TCM.

    HINT:
    Replace the TCM with the TCM of a normally functioning vehicle of the same model.

  1. Start the engine.

  1. Read the DTCs.

    Result:

    Display (DTC Output)
    		Proceed to
    P0100
    		A
    No DTC
    		B


B
REPLACE TCM
A

REPLACE ECM