1.Operation principle of engine immobiliser set (transponder key ECU control type)
When the ignition key is pulled out of the ignition key cylinder, the key unlock warning switch is turned off. The transponder key ECU detects this signal and sets the engine immobiliser system and the security indicator light continues to flash.
When the key is turned from the ON to ACC or LOCK position, and 20 seconds elapse in this condition, the transponder key ECU detects it from the terminal IG, sets the engine immobiliser system and continues flashing the security indicator light.
2.Operation principle of engine immobiliser unset (transponder key ECU control type)
(1)Inserting the ignition key
When the ignition key is inserted into the ignition key cylinder, the key unlock warning switch turns on. The transponder key ECU detects this signal and this ECU supplies power via the terminal VC5 to the transponder key amplifier and transmits the operation signal via the TXCT terminal. As a result, current is allowed to flow into the transponder key coil and produces a magnetic field around the key cylinder.
(2)Engine immobiliser system unset
With the magnetic field produced around the ignition key cylinder, the ID code signal registered in the transponder chip built in the key is transmitted to the transponder coil. The transponder key amplifier transmits this signal to the terminal CODE of the transponder key ECU.
The transponder key ECU checks this received key side ID code with the registered ID code. If the ECU judges that these signals match, it transmits and receives signals by using the special communication line (terminal EFIO and terminal EFII) to instruct “engine start permission” to the engine ECU, causing the engine immobiliser system to unset.
(3)Turning security indicator light off
When the transponder key ECU unsets the engine immobiliser system, the security indicator light flash control is finished and the light is turned off.
If the transponder key ECU’s terminal +B circuit becomes open, turning the ignition switch ON causes the backup power to be supplied to the transponder key ECU and starts the ID code matching.