Dtc U0100 Lost Communication With Ecm / Pcm A


DESCRIPTION

WIRING DIAGRAM

INSPECTION PROCEDURE

DISCONNECT CABLE FROM NEGATIVE BATTERY TERMINAL

CHECK FOR OPEN IN CAN BUS MAIN WIRE (ECM CAN MAIN WIRE)

CHECK HARNESS AND CONNECTOR (ECM - BATTERY AND BODY GROUND)

DTC U0100 Lost Communication with ECM / PCM "A"


DESCRIPTION


DTC Code
DTC Detection Condition
Trouble Area
U0100
There is no communication from the ECM.
  1. Power source or inside ECM
  2. ECM CAN main wire or connector
  3. ECM

WIRING DIAGRAM


Land Cruiser, Land Cruiser Prado. Grj150 Trj150,155 Kdj150,155 Lj150, Gdj150,155.Networking.Lin Communication System. Dtc U0100 Lost Communication With Ecm / Pcm A


INSPECTION PROCEDURE

NOTICE:
Inspect the fuses for circuits related to this system before performing the following inspection procedure.
HINT:
Operating the engine switch, any switches or any doors triggers related ECU and sensor communication with the CAN, which causes resistance variation.
1.DISCONNECT CABLE FROM NEGATIVE BATTERY TERMINAL

  1. Disconnect the cable from the negative (-) battery terminal before measuring the resistances of the CAN main wire and the CAN branch wire.

    CAUTION:
    Wait at least 90 seconds after disconnecting the cable from the negative (-) battery terminal to disable the airbag system.
    NOTICE:
    1. After turning the engine switch off, waiting time may be required before disconnecting the cable from the battery terminal. Therefore, make sure to read the disconnecting the cable from the battery terminal notice before proceeding with work (LandCruiser RM000003YMD00TX.html).
    2. When disconnecting the cable, some systems need to be initialized after the cable is reconnected (LandCruiser RM000003YMF011X.html).

NEXT


2.CHECK FOR OPEN IN CAN BUS MAIN WIRE (ECM CAN MAIN WIRE)


    Land Cruiser, Land Cruiser Prado. Grj150 Trj150,155 Kdj150,155 Lj150, Gdj150,155.Networking.Lin Communication System. Dtc U0100 Lost Communication With Ecm / Pcm A

  1. Disconnect the ECM connector.

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

    Standard Resistance:
    Tester Connection
    		Switch Condition
    		Specified Condition
    G57-20 (CANP) - G57-21 (CANN)
    		Engine switch off
    		108 to 132 Ω
Text in Illustration
*a
Front view of wire harness connector
(to ECM)


NG
REPAIR OR REPLACE ECM CAN MAIN WIRE OR CONNECTOR (CANP, CANN)
OK


3.CHECK HARNESS AND CONNECTOR (ECM - BATTERY AND BODY GROUND)
NOTICE:
When disconnecting the cable, some systems need to be initialized after the cable is reconnected (LandCruiser RM000003YMF011X.html).


  1. Connect the cable to the negative (-) battery terminal.


    Land Cruiser, Land Cruiser Prado. Grj150 Trj150,155 Kdj150,155 Lj150, Gdj150,155.Networking.Lin Communication System. Dtc U0100 Lost Communication With Ecm / Pcm A


    Text in Illustration
    *a
    		Front view of wire harness connector
    (to ECM)
    		-
    		-

  1. Disconnect the G57, G58 and C93 ECM connectors.

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

    Standard Resistance:
    Tester Connection
    		Condition
    		Specified Condition
    C93-1 (E1) - Body ground
    		Always
    		Below 1 Ω
    C93-12 (E01) - Body ground
    		Always
    		Below 1 Ω
    C93-13 (E02) - Body ground
    		Always
    		Below 1 Ω
    C93-8 (ME01) - Body ground
    		Always
    		Below 1 Ω
    G57-11 (EC) - Body ground
    		Always
    		Below 1 Ω

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

    Standard Voltage:
    Tester Connection
    		Condition
    		Specified Condition
    G57-23 (BATT) - Body ground
    		Always
    		11 to 14 V
    G57-17 (+B2) - Body ground
    		Battery positive (+) voltage applied to terminal G58-11 (MREL)
    		11 to 14 V
    G57-24 (+B) - Body ground
    		Battery positive (+) voltage applied to terminal G58-11 (MREL)
    		11 to 14 V


NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

REPLACE ECM (LandCruiser RM0000013Z002CX.html)