Lexus ES manuals

Lexus ES: Lost Communication with Power Source Control (B278C)

DESCRIPTION

When an internal malfunction is detected in the certification ECU (smart key ECU assembly), this DTC is stored.

DTC No.

Detection Item

DTC Detection Condition

Trouble Area

B278C

Lost Communication with Power Source Control

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 engine switch off, connect the Techstream to the DLC3 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.
  • Before replacing the certification ECU (smart key ECU assembly), refer to Registration.

    Click here

PROCEDURE

1.

CLEAR DTC

(a) Clear the DTCs.

Body Electrical > Smart Access > Clear DTCs
NEXT

2.

CHECK FOR DTC

(a) Check for DTCs.

Body Electrical > Smart Access > Trouble Codes

OK:

DTC B278C is not output.

OK

USE SIMULATION METHOD TO CHECK

NG

REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)

READ NEXT:

 No Response from ID BOX (B2789)

DESCRIPTION This DTC is stored when LIN communication between the certification ECU (smart key ECU assembly) and ID code box (immobiliser code ECU) stops for 10 seconds or more. DTC No. Detection

 No Response from Steering Lock ECU (B2786)

DESCRIPTION This DTC is stored when LIN communication between the certification ECU (smart key ECU assembly) and steering lock ECU (steering lock actuator or upper bracket assembly) stops for 10 secon

 Communication Malfunction between ECUs Connected by LIN (B2785)

DESCRIPTION If the certification ECU (smart key ECU assembly) detects a communication error with an ECU connected to the certification bus lines for 7 seconds or more, DTC B2785 will be stored. DTC

SEE MORE:

 Reassembly

REASSEMBLY PROCEDURE 1. INSTALL NO. 5 ROCKER PANEL MOULDING PROTECTOR HINT: When installing the No. 5 rocker panel moulding protector, heat the body rocker panel moulding assembly using a heat light. Heating Temperature Item Temperature Body Rocker Panel Moulding Assembly 20 to 30°C (68

 Components

COMPONENTS ILLUSTRATION *A for Driver Side *B for Front Passenger Side *1 COURTESY LIGHT ASSEMBLY *2 FRONT DOOR TRIM BOARD SUB-ASSEMBLY *3 MULTIPLEX NETWORK MASTER SWITCH ASSEMBLY WITH FRONT DOOR UPPER ARMREST BASE PANEL *4 NO. 2 DOOR TRIM PAD *5 POWER WINDOW REGU

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