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DTC    B279A    Theft Deterrent System Communication Line High Fixation

for Preparation Click here


DESCRIPTION

If the communication line (EFIO - IMI) to the certification ECU assembly (smart key ECU assembly)*1 or ID code box (immobiliser code ECU)*2 is stuck high output (e. g. shorted to +B), the power management control ECU (HV CPU) stores this DTC.
  1. *1: w/o Airbag Cut-off Switch
  2. *2: w/ Airbag Cut-off Switch

DTC No.
DTC Detection Condition
Trouble Area
B279A
When the communication line (EFIO - IMI) between power management control ECU (HV CPU) and certification ECU assembly (smart key ECU assembly)*1 or ID code box (immobiliser code ECU)*2 is stuck high output.
  1. Wire harness or connector
  2. Power management control ECU (HV CPU)
  3. Certification ECU (Smart key ECU assembly)*1
  4. ID code box (Immobiliser code ECU)*2
  1. *1: w/o Airbag Cut-off Switch
  2. *2: w/ Airbag Cut-off Switch

WIRING DIAGRAM


w/o Airbag Cut-off Switch

B203372E17


w/ Airbag Cut-off Switch

B203372E16


INSPECTION PROCEDURE

NOTICE:
  1. If the certification ECU (smart key ECU assembly) is replaced, register all the keys and ECU communication ID.*1
  2. If the ID code box (immobiliser code ECU) is replaced, register the ECU code and ECU communication ID.*2
    1. *1: w/o Airbag Cut-off Switch
    2. *2: w/ Airbag Cut-off Switch

1.CHECK DTC OUTPUT

  1. Clear the DTCs (Click here).

  1. Recheck for DTCs (Click here).

    HINT:
    If any DTCs other than DTC B279A are output, troubleshoot those DTCs first.

    Result:
    Result
    		Proceed to
    DTC B279A is output
    		A
    DTC B279A and other DTCs are output
    		B



B
GO TO DIAGNOSTIC TROUBLE CODE CHART (Click here)
A


2.SYSTEM CHECK

  1. Check the vehicle specification.

    Result:
    Result
    		Proceed to
    w/o Airbag Cut-off Switch
    		A
    w/ Airbag Cut-off Switch
    		B



B
Go to step 9
A


3.CHECK HARNESS AND CONNECTOR (CERTIFICATION ECU - POWER MANAGEMENT CONTROL ECU (HV CPU))

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



    B229596E02

  1. Disconnect the power management control ECU (HV CPU) connector.

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

    Standard Resistance:
    Tester Connection
    		Condition
    		Specified Condition
    L62-35 (EFIO) - L6-21 (IMI)
    		Always
    		Below 1 Ω
    L6-21 (IMI) - Body ground
    		Always
    		10 kΩ or higher

    Standard Voltage:
    Tester Connection
    		Condition
    		Specified Condition
    L6-21 (IMI) - Body ground
    		Always
    		Below 1 V

    Text in Illustration 
    *1
    		Front view of wire harness connector
    (to Certification ECU (Smart Key ECU Assembly))
    *2
    		Front view of wire harness connector
    (to Power Management Control ECU (HV CPU))



NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK


4.CHECK CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) (WAVEFORM)

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



  1. Reconnect the power management control ECU (HV CPU) connector.


    B229599E02

  1. Using an oscilloscope, check the waveform.

    Waveform (Reference):
    Item
    		Content
    Terminal No. (Symbol)
    		L62-35 (EFIO) - L62-15 (E)
    Tool Setting
    		5 V/DIV., 50 msec./DIV.
    Condition
    		Power switch on (IG)

    OK:
    Waveform is output normally (see illustration).


    Text in Illustration 
    *1
    		Component with harness connected
    (Certification ECU (Smart Key ECU Assembly))
    		*2
    		GND
    *3
    		HIGH
    		*4
    		LOW



NG
Go to step 5
OK

REPLACE POWER MANAGEMENT CONTROL ECU (HV CPU) (Click here)  

5.REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)

  1. Replace the certification ECU (smart key ECU assembly).


NEXT


6.KEY REGISTRATION

  1. Register the key.


NEXT


7.ECU COMMUNICATION ID REGISTRATION

  1. Register the ECU communication ID.


NEXT


8.CHECK DTC OUTPUT

  1. Clear the DTCs (Click here).

  1. Recheck for DTCs (Click here).

    OK:
    DTC B279A is not output.



NG
REPLACE POWER MANAGEMENT CONTROL ECU (HV CPU) (Click here)
OK

END (CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) WAS DEFECTIVE) 

9.CHECK HARNESS AND CONNECTOR (ID CODE BOX - POWER MANAGEMENT CONTROL ECU (HV CPU))

  1. Disconnect the ID code box (immobiliser code ECU) connector.



    B219313E04

  1. Disconnect the power management control ECU (HV CPU) connector.

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

    Standard Resistance:
    Tester Connection
    		Condition
    		Specified Condition
    L10-6 (EFIO) - L6-21 (IMI)
    		Always
    		Below 1 Ω
    L6-21 (IMI) - Body ground
    		Always
    		10 kΩ or higher

    Standard Voltage:
    Tester Connection
    		Condition
    		Specified Condition
    L6-21 (IMI) - Body ground
    		Always
    		Below 1 V

    Text in Illustration 
    *1
    		Front view of wire harness connector
    (to ID Code Box (Immobiliser Code ECU))
    *2
    		Front view of wire harness connector
    (to Power Management Control ECU (HV CPU))



NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK


10.CHECK ID CODE BOX (IMMOBILISER CODE ECU) (WAVEFORM)

  1. Reconnect the ID code box (immobiliser code ECU) connector.



    B232678E01

  1. Reconnect the power management control ECU (HV CPU) connector.

  1. Using an oscilloscope, check the waveform.

    Waveform (Reference):
    Item
    		Content
    Terminal No. (Symbol)
    		L10-6 (EFIO) - L10-8 (GND)
    Tool Setting
    		5 V/DIV., 50 msec./DIV.
    Condition
    		Power switch on (IG)

    OK:
    Waveform is output normally (see illustration).

    Text in Illustration 
    *1
    		Component with harness connected
    (ID Code Box (Immobiliser Code ECU))
    *2
    		GND
    *3
    		HIGH
    *4
    		LOW



NG
Go to step 11
OK

REPLACE POWER MANAGEMENT CONTROL ECU (HV CPU) (Click here)  

11.REPLACE ID CODE BOX (IMMOBILISER CODE ECU)

  1. Replace the ID code box (immobiliser code ECU).


NEXT


12.ECU CODE REGISTRATION

  1. Register the ECU code.


NEXT


13.ECU COMMUNICATION ID REGISTRATION

  1. Register the ECU communication ID.


NEXT


14.CHECK DTC OUTPUT

  1. Clear the DTCs (Click here).

  1. Recheck for DTCs (Click here).

    OK:
    DTC B279A is not output.



NG
REPLACE POWER MANAGEMENT CONTROL ECU (HV CPU) (Click here)
OK

END (ID CODE BOX (IMMOBILISER CODE ECU) WAS DEFECTIVE)