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:

A/C ECU Vehicle Information Reading/Writing Processor Malfunction (B15F5)
DESCRIPTION This DTC is stored when items controlled by the Air conditioning amplifier assembly cannot be customized via the navigation system vehicle customization screen. HINT: The Air conditioning amplifier assembly controls the air conditioning system related items that are customizable v ...

Power Source Mode does not Change to ON (IG and ACC)
DESCRIPTION If any of the following operations are performed, the certification ECU (smart key ECU assembly) receives a signal, and changes the power source mode. With the electrical key transmitter sub-assembly in the cabin, the engine switch is pressed. When the battery of the e ...

Heater Circuit (C1AAE)
DESCRIPTION If the forward recognition camera detects a malfunction in the camera heater (forward recognition hood) circuit, it will output a malfunction signal to the millimeter wave radar sensor assembly via CAN communication and DTC C1AAE will be stored. DTC No. Detect ...