Toyota Corolla (E120): Circuit description
The key unlock warning switch comes on when the ignition key is inserted in the key cylinder and goes off when the ignition key is removed.
Wiring diagram

Other materials:
Data list/active test
1. Data list
Hint:
using the data list displayed by the hand–held tester or the obd ii scan tool,
you can read the value of
the switches, sensors, actuators and so on without parts removal. Reading the
data list as a first step
of troubleshooting is one method to shorten diagnostic time.
...
Front passenger occupant classification system
Your vehicle is equipped with a front passenger occupant classification system.
This system detects the conditions of the front passenger seat and activates or
deactivates the devices for the front passenger.
1 SRS warning light
2 Seat belt reminder light
3 “AIR BAG OFF” indicator light ...
Wireless remote control/electronic key battery
Replace the battery with a new one if it is depleted.
You will need the following items:
● Flathead screwdriver
● Small flathead screwdriver
● Lithium battery CR2016 (vehicles without a smart key system), or CR2032 (vehicles
with a smart key system)
Replacing the battery
...


