Power Source Mode does not Change to ON (IG and ACC) [06/2018 - ]: Description

WARNING: This page does not describe the selected car, but rather 6 other vehicles, including the 2024 Lexus ES 300h, 2023 Lexus ES 300h, 2022 Lexus ES 300h, 2021 Lexus ES 300h, and 2020 Lexus ES 300h. However, it is still accessible from the selected car via links, so may be relevant.

When the power switch cannot be turned on (ACC) or on (IG), interior verification may be abnormal or there may be a malfunction in the ACC relay or IG relay circuit. If interior verification cannot be performed, the certification ECU (smart key ECU assembly) may be malfunctioning or communication may not be possible between the No. 1 indoor electrical key antenna assembly (front floor) or No. 2 indoor electrical key antenna assembly (rear floor) and the electrical key transmitter sub-assembly and door control receiver.

When an electrical key transmitter sub-assembly is brought into the cabin, its key ID code is compared with the key ID code stored in the certification ECU (smart key ECU assembly). If these codes do not match, key verification will fail and the power switch will not be able to be turned on (ACC) or on (IG).

When a door is unlocked and an electrical key transmitter sub-assembly is brought into the cabin, the certification ECU (smart key ECU assembly) activates the indoor electrical key antenna assemblies to form the interior detection area. The electrical key transmitter sub-assembly then responds to the detection signals with its key ID code. This response signal is received by the door control receiver and sent to the certification ECU (smart key ECU assembly).

RELATED DATA LIST AND ACTIVE TEST ITEMS

Problem Symptom	Data List and Active Test
Power source mode does not change to on (IG) or on (ACC)	Power Source Control Start Switch1 Start Switch2 IG Relay Monitor (Inside) ACC Relay Monitor IG Relay Monitor (Outside) Latch Circuit Power Supply Condition