Car access controls encompass components securing vehicle entry and operation. These systems utilize electronic key fobs, immobilizers, and associated receivers primarily within the vehicle’s body control module and engine control unit. Keyless entry systems employ radio frequency (RF) communication for remote locking/unlocking, while immobilizers prevent engine start without authorized key transponder data. Modern systems increasingly integrate push-button start, digital authentication, and smartphone connectivity via Bluetooth or dedicated mobile apps. Diagnostic interfaces enable reprogramming and fault code retrieval related to access control functionality.