Dtc B279A Theft Deterrent System Communication Line High Fixation

Vehicle Interior. Yaris. Ncp93, 131
Theft Deterrent Keyless Entry. Yaris. Ncp93, 131

DESCRIPTION

WIRING DIAGRAM

INSPECTION PROCEDURE

CHECK DTC OUTPUT

CHECK HARNESS AND CONNECTOR (TRANSPONDER KEY ECU - ECM)

PERFORM ACTIVE TEST USING ECM (INPUT)

REPLACE TRANSPONDER KEY ECU

REGISTER KEY

REGISTER ECU COMMUNICATION ID

CHECK DTC OUTPUT

DTC B279A Theft Deterrent System Communication Line High Fixation


DESCRIPTION

If the communication line (EFIO-IMI) to the transponder key ECU is stuck on HI output, the ECM outputs this DTC.

DTC No.
DTC Detection Condition
Trouble Area
B279A
Communication line (EFIO-IMI) between ECM and the transponder key ECU is stuck on HI output
  1. Wire harness
  2. Transponder key ECU
  3. ECM

WIRING DIAGRAM


Yaris. Ncp93, 131.Theft Deterrent Keyless Entry.Engine Immobiliser System (For Sedan). Dtc B279A Theft Deterrent System Communication Line High Fixation


INSPECTION PROCEDURE

NOTICE:
  1. If the transponder key ECU assembly is replaced, register the key and ECU communication ID (YARIS_NCP93 RM0000012FH00CX.html).
  2. If the ECM is replaced, register the ECU communication ID (YARIS_NCP93 RM0000012FH00CX.html).
1.CHECK DTC OUTPUT

  1. Recheck for DTCs (YARIS_NCP93 RM0000012FF00NX.html).

    HINT:
    If any DTCs other than DTC B279A are output, troubleshoot those DTCs first.
    Result:
    Result
    		Proceed to
    DTC B279A and other DTCs reoutput
    		A
    DTC B279A reoutput
    		B


A
GO TO DTC CHART (YARIS_NCP93 RM0000012F000PX.html)
B


2.CHECK HARNESS AND CONNECTOR (TRANSPONDER KEY ECU - ECM)

  1. Disconnect the D23 transponder key ECU connector.



  1. Disconnect the A21 ECM connector.


    Yaris. Ncp93, 131.Theft Deterrent Keyless Entry.Engine Immobiliser System (For Sedan). Dtc B279A Theft Deterrent System Communication Line High Fixation

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

    Standard Resistance:
    Tester Connection
    		Condition
    		Specified Condition
    D23-13 (EFIO) - A21-11 (IMI)
    		Always
    		Below 1 Ω
    D23-13 (EFIO) - Body ground
    		Always
    		10 kΩ or higher
    Standard Voltage:
    Tester Connection
    		Condition
    		Specified Condition
    D23-13 (EFIO) - Body ground
    		Always
    		Below 1 V


NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK


3.PERFORM ACTIVE TEST USING ECM (INPUT)

  1. Reconnect the transponder key ECU assembly connector.

  1. Reconnect the ECM connector.



  1. Measure the waveform.


    Yaris. Ncp93, 131.Theft Deterrent Keyless Entry.Engine Immobiliser System (For Sedan). Dtc B279A Theft Deterrent System Communication Line High Fixation

    Waveform 1 (Reference):
    Item
    		Content
    Terminal No. (Symbols)
    		A21-11 (IMI) - C20-104 (E1)
    Tool Setting
    		2 V/DIV., 1 s./DIV.
    Condition
    		Ignition switch ON
    OK:
    Normal waveform is output


NG
REPLACE ECM (YARIS_NCP93 RM000001CN002AX.html)
OK


4.REPLACE TRANSPONDER KEY ECU

  1. Replace the transponder key ECU assembly (YARIS_NCP93 RM000003BHZ005X.html).


NEXT


5.REGISTER KEY

  1. Register the key (YARIS_NCP93 RM0000012FH00CX.html).


NEXT


6.REGISTER ECU COMMUNICATION ID

  1. Register the ECU communication ID (YARIS_NCP93 RM0000012FH00CX.html).


NEXT


7.CHECK DTC OUTPUT

  1. Clear the DTCs (YARIS_NCP93 RM0000012FF00NX.html).

  1. Recheck for DTCs.

    OK:
    B279A is not reoutput.


NG
REPLACE ECM (YARIS_NCP93 RM000001CN002AX.html)
OK

END (TRANSPONDER KEY ECU IS DEFECTIVE)