The EIS is the electronic ignition switch where you insert the key or push the start button. Its job is to authenticate your key and tell the car’s systems it’s okay to start. It communicates with the key, steering lock ESL/EVL, ISM, and ECU. Once it verifies the key’s rolling code, it lets you turn the knob to start the engine or enables the push-button.
So it’s basically the car’s main security gatekeeper and ignition activator.
Why you must replace it:
1 No start condition - common reason
2 Steering lock failure
3 Key not recognized
4 Drains battery – A failing EIS can stay awake and cause parasitic drain.
5 Remove key error – It may not detect that the key
was removed, leaving ignition live.