Outline Of Electronic Key Operation

Operation 1 (Insert the Key into the Ignition Key Cylinder) 

1. By inserting the ignition key (electronic key: built-in transponder) into the key cylinder, the key detection switch is turned to ON.
2. The power is supplied from the NATS IMMU to NATS antenna amp. to antenna coil.
3. The current through the antenna coil induces a magnetic field.
4. The coil in the transponder induces electromotive force by mutual induction, which is charged in the capacitor.
5. The transponder uses the charged energy to transmit the built-in key ID signal.
6. The sent key ID signal is received by the antenna coil and transmitted via the NATS antenna amp. to NATS IMMU.
7. NATS IMMU compares the stored key ID and received one, and only if the matching result is OK, it transmits the key rotation permission signal to the steering lock control unit (integrated in the key cylinder).
8. When the key rotation permission signal is input, the steering lock control unit activates the electronic key solenoid valve in the key cylinder to allow the electronic key to turn.
9. Turn ignition switch ON.
10. Only if the key ID matching result is OK, the ECM allows the engine to start.

Operation 2 (Withdraw the Key from the Ignition Key Cylinder) 

1. Return the electronic key to the LOCK position of the steering system lock.
2. When the key is removed, the electronic key solenoid valve in the key cylinder returns to inhibit the key from turning. In this case, the steering lock control unit processes the key switch ON OFF signal by itself to inhibit the electronic key from turning.

Fig 1: View Of Electronic Key System

Courtesy of NISSAN MOTOR CO., U.S.A.