Toyota 4Runner: No Response from ID BOX (B2789)

Toyota 4Runner Service Manual / Power Source / Network / Networking / Lin Communication System / No Response from ID BOX (B2789)

DESCRIPTION

This DTC is stored when LIN communication between the certification ECU and ID code box stops for 10 seconds or more.

DTC Code	DTC Detection Condition	Trouble Area
B2789	No communication between the certification ECU and ID code box for 10 seconds or more.	ID code box Certification ECU Harness or connector

WIRING DIAGRAM

CAUTION / NOTICE / HINT

NOTICE:

When using the Techstream with the ignition switch off to troubleshoot:
Connect the Techstream to the vehicle and turn a courtesy light switch on and off at 1.5 second intervals until communication between the Techstream and vehicle begins.
Inspect the fuses and bulbs for circuits related to this system before performing the following inspection procedure.

HINT:

When communication between the ID code box and certification ECU stops, DTC B2785 is also stored.

PROCEDURE

CLEAR DTC

(a) Clear the DTCs (See page ).

2.	CHECK FOR DTC

(a) Check for DTCs (See page ).

OK:

DTC B2789 is not output.

USE SIMULATION METHOD TO CHECK

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

(a) Disconnect the F79 certification ECU connector.

(b) Disconnect the F72 ID code box connector.

Standard Resistance:

Tester Connection	Condition	Specified Condition
F79-29 (LIN) - F72-3 (LIN1)	Always	Below 1 Ω
F79-29 (LIN) or F72-3 (LIN1) - Body ground	Always	10 kΩ or higher

REPAIR OR REPLACE HARNESS OR CONNECTOR

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

(a) Disconnect the F72 ID code box connector.

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

Standard Resistance:

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

Standard Voltage:

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

Text in Illustration

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

REPAIR OR REPLACE HARNESS OR CONNECTOR

5.	REPLACE ID CODE BOX

(a) Temporarily replace the ID code box with a new one (See page ).

CLEAR DTC

(a) Clear the DTCs (See page ).

7.	CHECK FOR DTC

(a) Check for DTCs (See page ).

OK:

DTC B2789 is not output.

END (ID CODE BOX IS DEFECTIVE)

REPLACE CERTIFICATION ECU

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