Toyota 4Runner: LIN Communication Master Malfunction (B2287,B278C)

Toyota 4Runner Service Manual / Power Source / Network / Networking / Lin Communication System / LIN Communication Master Malfunction (B2287,B278C)

DESCRIPTION

DTC B2287 is stored when there is an open or short circuit or an ECU communication malfunction between the power management control ECU and certification ECU.
DTC B278C is stored when LIN communication between the certification ECU and power management control ECU stops for 10 seconds or more.

DTC Code	DTC Detection Condition	Trouble Area
B2287	There is an open or short circuit or an ECU communication malfunction between the power management control ECU and certification ECU.	Certification ECU Power management control ECU Harness or connector
B278C	No communication between the certification ECU and power management control ECU for 10 seconds or more.	Certification ECU Power management control 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 DTC B2287, B278C and B2785 are output simultaneously, perform troubleshooting for DTC B2785 first (See page ).

PROCEDURE

CLEAR DTC

(a) Clear the DTCs (See page ).

2.	CHECK FOR DTC

(a) Check for DTCs (See page ).

OK:

DTC B2287 or B278C is not output.

USE SIMULATION METHOD TO CHECK

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

(a) Disconnect the F79 certification ECU connector.

(b) Disconnect the F80 power management control ECU connector.

Standard Resistance:

Tester Connection	Condition	Specified Condition
F79-29 (LIN) - F80-24 (LIN2)	Always	Below 1 Ω
F79-29 (LIN) or F80-24 (LIN2) - Body ground	Always	10 kΩ or higher

REPAIR OR REPLACE HARNESS OR CONNECTOR

4.	CHECK HARNESS AND CONNECTOR (POWER MANAGEMENT CONTROL ECU - BATTERY AND BODY GROUND)

(a) Disconnect the F80 power management control ECU connector.

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
F80-5 (GND2) - Body ground	Always	Below 1 Ω
F80-6 (GND) - Body ground	Always	Below 1 Ω

Standard Voltage:

Tester Connection	Condition	Specified Condition
F80-1 (AM22) - Body ground	Always	11 to 14 V
F80-2 (AM21) - Body ground	Always	11 to 14 V

Text in Illustration

*a	Rear view of wire harness connector (to Power Management Control ECU)

REPAIR OR REPLACE HARNESS OR CONNECTOR

5.	REPLACE POWER MANAGEMENT CONTROL ECU

(a) Temporarily replace the power management control ECU with a new or normally functioning one (See page ).

CLEAR DTC

(a) Clear the DTCs (See page ).

7.	CHECK FOR DTC

(a) Check for DTCs (See page ).

OK:

DTC B2287 or B278C is not output.

END (POWER MANAGEMENT CONTROL ECU IS DEFECTIVE)

REPLACE CERTIFICATION ECU

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