Toyota Tacoma (2015-2018) Service Manual: System Diagram - Steering Lock System

SYSTEM DIAGRAM

Circuit Description

Component	Outline
Steering Lock ECU (Steering Lock Actuator or UPR Bracket Assembly)	The steering is locked and unlocked by communicating with the certification ECU (smart key ECU assembly) via LIN communication. When the following conditions are met, the steering can be unlocked. The codes (L codes) of the certification ECU (smart key ECU assembly) and steering lock match. The certification ECU (smart key ECU assembly) and key ID codes match.
Certification ECU (Smart Key ECU Assembly)	The ID code of the key the user is carrying is sent to the electrical key antenna. The certification ECU (smart key ECU assembly) compares the key ID code it receives from the electrical key antenna with its own ID code. If they match, the certification ECU (smart key ECU assembly) permits the steering lock ECU (steering lock actuator or UPR bracket assembly) to turn the power on, start the engine and unlock and lock the steering. Outputs a command to supply power to the steering lock motor based on the power source mode, shift position and vehicle speed signal.

Component

Outline

Steering Lock ECU (Steering Lock Actuator or UPR Bracket Assembly)

The steering is locked and unlocked by communicating with the certification ECU (smart key ECU assembly) via LIN communication.
When the following conditions are met, the steering can be unlocked.
- The codes (L codes) of the certification ECU (smart key ECU assembly) and steering lock match.
- The certification ECU (smart key ECU assembly) and key ID codes match.

Certification ECU (Smart Key ECU Assembly)

The ID code of the key the user is carrying is sent to the electrical key antenna.
The certification ECU (smart key ECU assembly) compares the key ID code it receives from the electrical key antenna with its own ID code. If they match, the certification ECU (smart key ECU assembly) permits the steering lock ECU (steering lock actuator or UPR bracket assembly) to turn the power on, start the engine and unlock and lock the steering.
Outputs a command to supply power to the steering lock motor based on the power source mode, shift position and vehicle speed signal.