Toyota 4Runner: Theft Deterrent System Communication Line High Fixation (B279A)

Toyota 4Runner Service Manual / Vehicle Interior / Theft Deterrent / Keyless Entry / Engine Immobiliser System(w/ Smart Key System) / Theft Deterrent System Communication Line High Fixation (B279A)

DESCRIPTION

If the communication line (EFIO-IMI) to the ID code box is stuck on HI output, the ECM stores this DTC.

DTC Code	DTC Detection Condition	Trouble Area
B279A	The communication line (EFIO-IMI) between the ECM and the ID code box is stuck on HI output.	Harness or connector ID code box ECM

WIRING DIAGRAM

CAUTION / NOTICE / HINT

NOTICE:

When the ID code box is replaced, refer to Registration (See page ).

Inspect the fuses for circuits related to this system before performing the following inspection procedure.

PROCEDURE

CLEAR DTC

(a) Clear the DTCs (See page ).

2.	CHECK FOR DTC

(a) Check for DTCs (See page ).

HINT:

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

Result

Result	Proceed to
DTC B279A is not output	A
DTC B279A and other DTCs are output	B
DTC B279A is output	C

USE SIMULATION METHOD TO CHECK

Go to DIAGNOSTIC TROUBLE CODE CHART

3.	CHECK HARNESS AND CONNECTOR (ID CODE BOX - ECM)

(a) Disconnect the F72 box connector.

(b) Disconnect the F50 ECM connector.

Standard Resistance:

Tester Connection	Condition	Specified Condition
F72-6 (EFIO) - F50-14 (IMI)	Always	Below 1 Ω
F72-6 (EFIO) or F50-14 (IMI) - Body ground	Always	10 kΩ or higher

REPAIR OR REPLACE HARNESS OR CONNECTOR

4.	CHECK ID CODE BOX (OUTPUT)

(a) Using an oscilloscope, check the waveform.

Text in Illustration

Component with harness connected

(ECM)

Measurement Condition

Item	Content
Tester Connection	F50-14 (IMI) - Body ground
Tool Setting	10 V/DIV., 100 ms./DIV.
Condition	Engine switch on (IG)

OK:

Waveform is output normally (refer to illustration).

REPLACE ECM

5.	CHECK HARNESS AND CONNECTOR (ID CODE BOX - BATTERY AND BODY GROUND)

(a) Disconnect the F72 box connector.

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

Standard Voltage:

Tester Connection	Condition	Specified Condition
F72-1 (+B) - Body ground	Always	11 to 14 V

Standard Resistance:

Tester Connection	Condition	Specified Condition
F72-8 (GND) - Body ground	Always	Below 1 Ω

Text in Illustration

*a	Front view of wire harness connector (to ID Code Box)

REPAIR OR REPLACE HARNESS OR CONNECTOR

6.	REPLACE ID CODE BOX

(a) Replace the ID code box (See page ).

7.	REGISTER RECOGNITION CODES

(a) Register the recognition codes in the ECUs (See page ).

8.	REGISTER ECU COMMUNICATION ID

(a) Register the ECU communication ID (See page ).

CLEAR DTC

(a) Clear the DTCs (See page ).

10.	CHECK FOR DTC

(a) Check for DTCs (See page ).

OK:

DTC B279A is not output.

END (ID CODE BOX IS DEFECTIVE)

REPLACE ECM

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