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 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 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


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 MAIN WIRE)


  1. Disconnect the G56*1 or G57*2 ECM connector.

    1. *1: for 1GR-FE and Manual Transmission System
    2. *2: for 1KD-FTV

    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
for 1GR-FE and Manual Transmission System
*B
for 1KD-FTV
*a
Front view of wire harness connector
(to ECM)
-
-

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

    Standard Resistance:
    for 1GR-FE and Manual Transmission System
    Tester Connection
    		Switch Condition
    		Specified Condition
    G56-34 (CANP) - G56-33 (CANN)
    		Engine switch off
    		108 to 132 Ω
    for 1KD-FTV
    Tester Connection
    		Switch Condition
    		Specified Condition
    G57-20 (CANP) - G57-21 (CANN)
    		Engine switch off
    		108 to 132 Ω


NG
REPAIR OR REPLACE ECM 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. for 1GR-FE and Manual Transmission System:



    1. Disconnect the C36, C37 and G55 ECM connectors.


      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)
      		-
      		-

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

      Standard Resistance:
      Tester Connection
      		Condition
      		Specified Condition
      C36-12 (E1) - Body ground
      		Always
      		Below 1 Ω
      C37-14 (E01) - Body ground
      		Always
      		Below 1 Ω
      C37-15 (E02) - Body ground
      		Always
      		Below 1 Ω
      C37-10 (ME01) - Body ground
      		Always
      		Below 1 Ω
      G55-12 (EC) - Body ground
      		Always
      		Below 1 Ω

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

      Standard Voltage:
      Tester Connection
      		Condition
      		Specified Condition
      G55-24 (BATT) - Body ground
      		Always
      		11 to 14 V
      G55-23 (+B2) - Body ground
      		Battery positive (+) voltage applied to terminal G55-9 (MREL)
      		11 to 14 V
      G55-22 (+B) - Body ground
      		Battery positive (+) voltage applied to terminal G55-9 (MREL)
      		11 to 14 V


  1. for 1KD-FTV:



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


      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)
      		-
      		-

    2. 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

    3. 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
Result
Result
Proceed to
OK (for 1GR-FE)
A
OK (for 1KD-FTV)
B
NG
C


B
REPLACE ECM (LandCruiser RM0000013Z002CX.html)

C
REPAIR OR REPLACE HARNESS OR CONNECTOR
A

REPLACE ECM (LandCruiser RM00000329203TX.html)