Lexus ES: Lost Communication with Power Source Control (B278C)
Lexus ES (XZ10) Service Manual / Power Source & Network / Networking / Lin Communication System (for Hv Model) / 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 power 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.
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PROCEDURE
| 1. | CLEAR DTC |
(a) Clear the DTCs.
Body Electrical > Smart Access > Clear DTCs
|
| 2. | CHECK FOR DTC |
(a) Check for DTCs.
Body Electrical > Smart Access > Trouble CodesOK:
DTC B278C is not output.
| OK |  | USE SIMULATION METHOD TO CHECK |
| NG | | REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) |
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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
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into the seats
Press the "MENU" button on the
Remote Touch and select "Climate"
to display the air conditioning control
s
Inspection
INSPECTION PROCEDURE 1. INSPECT OUTER MIRROR RH (a) Check the outer mirror heater operation. (1) Measure the resistance according to the value(s) in the table below. Standard Resistance: Tester Connection Condition Specified Condition 1 - 2 25°C (77°F) 3.8 to 5.8 Ω If the re
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