Toyota Yaris: Smart Key System (for Start Function) / ID-BOX Component Internal Failure (B278D96)

Toyota Yaris XP210 (2020-2025) Reapir and Service Manual / Vehicle Interior / Theft Deterrent / Keyless Entry / Smart Key System (for Start Function) / ID-BOX Component Internal Failure (B278D96)

DESCRIPTION

When the certification ECU (smart key ECU assembly) detects an input signal indicating that the vehicle is equipped with an ID code box even though the ID code box is not registered, the certification ECU (smart key ECU assembly) stores this DTC.

DTC No.	Detection Item	DTC Detection Condition	Trouble Area	Note
B278D96	ID-BOX Component Internal Failure	One of the following conditions is met: The certification ECU (smart key ECU assembly) recognizes that the wire harness judging whether the vehicle is equipped with an ID code box or not is provided even though the ID code box is not registered. The certification ECU (smart key ECU assembly) receives a LIN signal from the ID code box even though the ID code box is not registered. The certification ECU (smart key ECU assembly) receives a LIN signal from the ID code box even though the wire harness judging whether the vehicle is equipped with an ID code box or not is not provided.	Misconnection of the ID code box	DTC output confirmation operation: Always

Vehicle Condition and Fail-safe Operation when Malfunction Detected

Vehicle Condition when Malfunction Detected	Fail-safe Operation when Malfunction Detected
Key registration will be prohibited	-

Related Data List and Active Test

DTC No.	Data List and Active Test
B278D96	-

CAUTION / NOTICE / HINT

NOTICE:

When using the GTS with the engine switch off, connect the GTS to the DLC3 and turn a courtesy light switch on and off at intervals of 1.5 seconds or less until communication between the GTS and the vehicle begins. Then select Model Code "KEY REGIST" under manual mode and enter the following menus: Body Electrical / Smart Key. While using the GTS, periodically turn a courtesy light switch on and off at intervals of 1.5 seconds or less to maintain communication between the GTS and the vehicle.
The smart key system (for Start Function) uses the LIN communication system and CAN communication system. Inspect the communication function by following How to Proceed with Troubleshooting. Troubleshoot the smart key system (for Start Function) after confirming that the communication systems are functioning properly.
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Before performing following procedure, check that the ID code box (immobiliser code ECU) is not installed on the vehicle.
Before replacing the certification ECU (smart key ECU assembly), refer to the Registration.
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After repair, confirm that no DTCs are output by performing "DTC Output Confirmation Operation".

PROCEDURE

CLEAR DTC

(a) Clear the DTCs.

Body Electrical > Smart Key > Clear DTCs

2.	CHECK FOR DTC

(a) Check for DTCs.

Body Electrical > Smart Key > Trouble Codes

HINT:

Before checking for DTCs, perform the "DTC Output Confirmation Operation" procedure.

Result	Proceed to
DTC B278D96 is not output.	A
DTC B278D96 is output.	B

END

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