Toyota Tacoma (2015-2018) Service Manual: System Description

SYSTEM DESCRIPTION

1. ENGINE IMMOBILISER SYSTEM DESCRIPTION

(a) The engine immobiliser system determines whether or not to enable starting of the SFI system based on a comparison of the key ID code and the vehicle pre-registered code. The engine immobiliser system compares the vehicle certification ECU (smart key ECU assembly) pre-registered ID code with the key-embedded transponder chip ID code. If the ID codes do not match, the engine immobiliser system activates and the SFI system cannot be started. The certification ECU (smart key ECU assembly ) manages communication with the SFI system and steering lock ECU (steering lock actuator or upr bracket assembly). When the ID codes of the transponder chip and certification ECU (smart key ECU assembly) match, the certification ECU (smart key ECU assembly) authorizes the starting of the SFI system.

2. SYSTEM FUNCTION

(a) Push-button start function

(1) When the driver (or an occupant) gets in the vehicle and depresses the brake pedal while carrying the key, the certification ECU (smart key ECU assembly) generates a request signal and sends it to the indoor electrical key oscillator. When the request signal is received, the indoor electrical key oscillator sends another request signal in order to detect whether the key is inside the vehicle. When the key receives this request signal, it sends back an ID code which includes a response code. The ID code sent from the key is sent to the certification ECU (smart key ECU assembly) via the door control receiver. When the ID code is received, the certification ECU (smart key ECU assembly) analyzes the code. If the certification result is normal, the smart warning light is displayed on the multi-information display. When the smart warning light illuminates is displayed, and the driver presses the engine switch, the certification ECU (smart key ECU assembly) recognizes the engine start signal, turns the ACC relay on and turns the IG1 and IG2 relays on in that order after 0.025 seconds. At this time, the certification ECU (smart key ECU assembly) confirms that the power source mode has changed and supplies the steering lock actuator with power. Then the steering lock ECU (steering lock actuator or upr bracket assembly) confirms that the certification ECU (smart key ECU assembly) is the proper ECU and operates the steering lock actuator motor until the steering lock is unlocked. After the steering lock is unlocked, the steering lock ECU (steering lock actuator or upr bracket assembly) sends an unlock completion signal to the certification ECU (smart key ECU assembly). When this signal is received, the certification ECU (smart key ECU assembly) sends an immobiliser unset command signal to the SFI system after confirming that the certification ECU (smart key ECU assembly) is the proper ECU. Then the certification ECU (smart key ECU assembly) sends a security indicator light off signal to the air conditioning control assembly.