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:

Open in Stop Light Switch Circuit (C1425)
DESCRIPTION The skid control ECU (brake actuator assembly) detects the brake operating conditions through a signal transmitted by the stop light switch. The skid control ECU incorporates a circuit to detect an open circuit. This DTC is output when an open circuit is detected in the stop light ...

Dtc Check / Clear
DTC CHECK / CLEAR 1. CHECK DTC (a) Connect the Techstream to the DLC3. (b) Turn the ignition switch ON. (c) Turn the Techstream on. (d) Enter the following menus: Body Electrical / Main Body / Trouble Codes. (e) Check for DTCs. 2. CLEAR DTC (a) Connect the Techstream to the DLC3. (b) Turn t ...

Pattern Select Switch Power Mode Circuit
DESCRIPTION The ECM memory contains the programs for the normal and PWR shift patterns. By following the programs corresponding to the signals from the pattern select switch assembly, park/neutral position switch and other various sensors, the ECM switches the shift solenoid valves on and off, ...