Intelligent Switching Unit Description and Operation: Tasks

The intelligent switching unit (ISU) is the car-body control unit, which realizes some functions as actuators controls, vehicle access controls, or alarm functions.

The Immobilizer function is shared between the ISU and the engine control module (ECM) control units.

The Immobilizer tasks of the ISU are:

• Communication with the key transponder after the ignition ON transition (identification and authentication of the key, learning of the keys)
• Communication with the ECM control unit after the ignition ON transition (receipt of the ECM request and transmission of release message)
• Control of the immobilizer status indicator (LED)
• Communication with the diagnosis tester, such as keys learning, diagnostic