Toyota Tacoma (2015-2018) Service Manual: Lost Communication with Power Source Control (B278C)

Toyota Tacoma (2015-2018) Service Manual / Multiplex Communication / Lin Communication System / Lost Communication with Power Source Control (B278C)

DESCRIPTION

DTC No.	DTC Detection Condition	Trouble Area
B278C	An internal malfunction occurs in the certification ECU (smart key ECU assembly)	Certification ECU (smart key ECU assembly)

CAUTION / NOTICE / HINT

NOTICE:

When using the Techstream with the vehicle ignition switch off, connect the Techstream to the vehicle and turn a courtesy light switch on and off at intervals of 1.5 seconds or less until communication between the Techstream and the vehicle begins. Then select the vehicle type under manual mode and enter the following menus: Body Electrical / Smart Access. While using the Techstream, periodically turn a courtesy light switch on and off at intervals of 1.5 seconds or less to maintain communication between the Techstream and the vehicle.
If the certification ECU (smart key ECU assembly) is replaced, register the keys (See page ).

PROCEDURE

CLEAR DTC

(a) Clear the DTCs (See page ).

2.	CHECK FOR DTC

(a) Check for DTCs (See page OK: ).

OK:

DTC B278C is not output.

USE SIMULATION METHOD TO CHECK

REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)

P/W Master Switch Communication Stop (B1206)

DESCRIPTION This DTC is stored when LIN communication between the power window regulator master switch assembly and main body ECU (multiplex network body ECU) stops for 10 seconds or more. ...

Front Passenger Side Door ECU Communication Stop (B2322)

DESCRIPTION This DTC is stored when LIN communication between the front power window regulator motor assembly RH and main body ECU (multiplex network body ECU) stops for 10 seconds or more. ...

Other materials:

Speed Signal Malfunction (B15C2)
DESCRIPTION The navigation receiver assembly receives a vehicle speed signal from the combination meter assembly and information from the navigation antenna assembly, and then adjusts the vehicle position. The navigation receiver assembly stores this DTC when the difference between the speed ...

Open in Driver Side Electrical Antenna Circuit (B27A1)
DESCRIPTION The certification ECU (smart key ECU assembly) generates a request signal and transmits the signal to the front door outside handle assembly LH [electrical key antenna] at intervals of 0.25 seconds. For the front door outside handle assembly LH [electrical key antenna] to detect w ...

Main Body ECU Vehicle Information Reading/Writing Process Malfunction (B15F6)
DESCRIPTION This DTC is stored when items controlled by the main body ECU (multiplex network body ECU) cannot be customized via the audio and visual system vehicle customization screen. HINT: The main body ECU (multiplex network body ECU) controls the items for the following systems th ...