Toyota 4Runner: No Response from Steering Lock ECU (B2786)

Toyota 4Runner Service Manual / Power Source / Network / Networking / Lin Communication System / No Response from Steering Lock ECU (B2786)

DESCRIPTION

This DTC is stored when LIN communication between the certification ECU and steering lock actuator assembly (steering lock ECU) stops for 10 seconds or more.

DTC Code	DTC Detection Condition	Trouble Area
B2786	LIN communication between the certification ECU and steering lock ECU stops for 10 seconds or more.	Steering lock actuator assembly (steering lock ECU) 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 steering lock ECU 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 B2786 is not output.

USE SIMULATION METHOD TO CHECK

3.	CHECK HARNESS AND CONNECTOR (CERTIFICATION ECU - STEERING LOCK ECU)

(a) Disconnect the F79 certification ECU connector.

(b) Disconnect the F68 steering lock actuator assembly (steering lock ECU) connector.

Standard Resistance:

Tester Connection	Condition	Specified Condition
F79-29 (LIN) - F68-5 (LIN)	Always	Below 1 Ω
F79-29 (LIN) or F68-5 (LIN) - Body ground	Always	10 kΩ or higher

REPAIR OR REPLACE HARNESS OR CONNECTOR

4.	CHECK HARNESS AND CONNECTOR (STEERING LOCK ECU - BATTERY AND BODY GROUND)

(a) Disconnect the F68 steering lock actuator assembly (steering lock ECU) connector.

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
F68-1 (GND) - Body ground	Always	Below 1 Ω

Standard Voltage:

Tester Connection	Switch Condition	Specified Condition
F68-6 (IG2) - Body ground	Ignition switch ON	11 to 14 V
F68-7 (B) - Body ground	Always	11 to 14 V

Text in Illustration

*a	Front view of wire harness connector (to Steering Lock Actuator Assembly [Steering Lock ECU])

REPAIR OR REPLACE HARNESS OR CONNECTOR

5.	REPLACE STEERING LOCK ACTUATOR ASSEMBLY (STEERING LOCK ECU)

(a) Temporarily replace the steering lock actuator (steering lock ECU) assembly 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 B2786 is not output.

END (STEERING LOCK ECU IS DEFECTIVE)

REPLACE CERTIFICATION ECU

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