DTC B278E-87: Immobiliser Amp Missing Message [11/2021 - ]: Procedure

WARNING: This page is about a different car, the 2025 Lexus NX 350h, 2024 Lexus NX 350h, 2023 Lexus NX 350h, and 2022 Lexus NX 350h. However, it is still accessible from the selected car via links, so may be relevant.

CLEAR DTC

Clear the DTCs.

Body Electrical > Smart Access > Clear DTCs

Result

Proceed to
NEXT

Result:

See step 2

CHECK FOR DTC

Press the power switch with the electric key transmitter sub-assembly not in the cabin.

Check for DTCs.

Body Electrical > Smart Access > Trouble Codes

Result

Result	Proceed to
DTC B278E-87 is output	A
DTC B278E-87 is not output	B

Result:

REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY). Refer to REMOVAL [11/2021 - ]

Result:

USE SIMULATION METHOD TO CHECK. Refer to HOW TO PROCEED WITH TROUBLESHOOTING [11/2021 - ]