Dtc B278A Short To Gnd In Immobiliser System Power Source Circuit

Vehicle Interior. Land Cruiser. Urj200, 202 Grj200 Vdj200
Theft Deterrent Keyless Entry. Land Cruiser. Urj200, 202 Grj200 Vdj200

DESCRIPTION

WIRING DIAGRAM

INSPECTION PROCEDURE

CHECK CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)

CHECK HARNESS AND CONNECTOR (CERTIFICATION ECU [SMART KEY ECU ASSEMBLY] - ENGINE SWITCH)

CHECK CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)

DTC B278A Short to GND in Immobiliser System Power Source Circuit


DESCRIPTION

When there is a short to GND in the power supply for the transponder key amplifier of the engine switch, the certification ECU (smart key ECU assembly) stores this DTC.

DTC Code
DTC Detection Condition
Trouble Area
B278A
A short to GND in the power supply of the transponder key amplifier of the engine switch (VC5 - VC5) detected. (1 trip detection logic)*
  1. Engine switch
  2. Certification ECU (smart key ECU assembly)
  3. Harness or connector
  1. *: Only output while a malfunction is present.

Vehicle Condition and Fail-safe Operation when Malfunction Detected
Vehicle Condition when Malfunction Detected
Fail-safe Operation when Malfunction Detected
Engine cannot be started when transmitter battery is depleted by holding transmitter near engine switch and pressing and holding engine switch with shift lever in P
-

Related Data List and Active Test
DTC Code
Data List and Active Test
B278A
-

WIRING DIAGRAM


Land Cruiser. Urj200, 202 Grj200 Vdj200.Theft Deterrent Keyless Entry.Entry And Start System (For Entry Function). Dtc B278A Short To Gnd In Immobiliser System Power Source Circuit


INSPECTION PROCEDURE

NOTICE:
  1. When using the GTS with the engine switch off, connect the GTS to the DLC3 and turn a courtesy light switch on and off at intervals of 1.5 seconds or less until communication between the GTS and the vehicle begins. Then select Model Code "KEY REGIST" under manual mode and enter the following menus: Body Electrical / Entry&Start (CAN). While using the GTS, periodically turn a courtesy light switch on and off at intervals of 1.5 seconds or less to maintain communication between the GTS and the vehicle.
  2. Before replacing the certification ECU (smart key ECU assembly), refer to Service Bulletin.
  3. After repair, confirm that no DTCs are output by performing "DTC Output Confirmation Operation."
1.CHECK CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)


  1. Using an oscilloscope, check the waveform.


    Land Cruiser. Urj200, 202 Grj200 Vdj200.Theft Deterrent Keyless Entry.Entry And Start System (For Entry Function). Dtc B278A Short To Gnd In Immobiliser System Power Source Circuit


    Text in Illustration
    *a
    		Component with harness connected
    (Engine Switch)
    		-
    		-

    Measurement Condition:

    Tester Connection
    		Condition
    		Tool Setting
    		Specified Condition
    E123-10 (VC5) - E123-6 (AGND)
    		Engine switch off, key not in cabin, within 30 seconds after engine switch pressed
    		2 V/DIV., 200 ms./DIV.
    		Pulse generation
    OK:
    The waveform is similar to that shown in the illustration.

    Result:

    Result
    		Proceed to
    OK (for 3UR-FE)
    		A
    OK (for 1UR-FE)
    		B
    OK (for 1GR-FE)
    		C
    OK (for 1VD-FTV)
    		D
    NG
    		E


B
REPLACE ENGINE SWITCH (Click here)

C
REPLACE ENGINE SWITCH (Click here)

D
REPLACE ENGINE SWITCH (Click here)

E
Go to step 2
A

REPLACE ENGINE SWITCH (Click here)

2.CHECK HARNESS AND CONNECTOR (CERTIFICATION ECU [SMART KEY ECU ASSEMBLY] - ENGINE SWITCH)

  1. Disconnect the E130 certification ECU (smart key ECU assembly) connector.

  1. Disconnect the E123 engine switch connector.

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

    Standard Resistance:
    Tester Connection
    		Condition
    		Specified Condition
    E130-15 (VC5) - E123-10 (VC5)
    		Always
    		Below 1 Ω
    E130-12 (AGND) - E123-6 (AGND)
    		Always
    		Below 1 Ω
    E130-15 (VC5) or E123-23 (VC5) - Body ground
    		Always
    		10 kΩ or higher
    E130-12 (AGND) or E123-6 (AGND) - Body ground
    		Always
    		10 kΩ or higher


NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK


3.CHECK CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)


  1. Reconnect the E130 certification ECU (smart key ECU assembly) connector.


    Land Cruiser. Urj200, 202 Grj200 Vdj200.Theft Deterrent Keyless Entry.Entry And Start System (For Entry Function). Dtc B278A Short To Gnd In Immobiliser System Power Source Circuit


    Text in Illustration
    *a
    		Component with harness connected
    (Certification ECU [Smart Key ECU Assembly])
    		-
    		-

  1. Reconnect the E123 engine switch connector.

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

    Standard Voltage:
    Tester Connection
    		Condition
    		Specified Condition
    E130-15 (VC5) - E130-12 (AGND)
    		Engine switch off, brake pedal not depressed, 30 seconds or more elapsed after driver door opened and then closed
    		Below 1 V
Result
Result
Proceed to
OK (for 3UR-FE)
A
OK (for 1UR-FE)
B
OK (for 1GR-FE)
C
OK (for 1VD-FTV)
D
NG
E


B
REPLACE ENGINE SWITCH (Click here)

C
REPLACE ENGINE SWITCH (Click here)

D
REPLACE ENGINE SWITCH (Click here)

E
REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)
A

REPLACE ENGINE SWITCH (Click here)