The tables below summarize the input and output signals to the units in the system for the immobilizer. The signal types are divided into directly connected signals, serial communication and controller area network (CAN) communication.

Central electronic module (CEM) (4/56)

Input signals	Output signals
Directly connected:	Directly connected:
Input signals from the switches for the different key positions (I, II, III) in the ignition switch.	Starter motor relay for activating the starter motor.
Via serial communication (LIN):	Via serial communication (LIN):
Antenna ring for communication with the key.	Antenna ring for communication with the key.
Via CAN communication (LS-CAN):	Via CAN communication (LS-CAN):
-	Driver information module (DIM) for displaying messages.
Via CAN communication (HS-CAN):	Via CAN communication (HS-CAN):
Engine control module (ECM) with information about the status of the engine for the immobilizer function.	Engine control module (ECM) for communication and to check the identity.

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Antenna ring (16/65)

Input signals	Output signals
Via serial communication:	Via serial communication:
Central electronic module (CEM) for communication with the key.	Central electronic module (CEM) for communication with the key.

Engine control module (ECM) (4/46)

Input signals	Output signals
Via CAN communication (HS-CAN):	Via CAN communication (HS-CAN):
Communication with the central electronic module (CEM) during start attempts.	Information about the status of the engine Communication with the central electronic module (CEM) during start attempts.

Driver information module (DIM) (5/1)

Input signals	Output signals
Via CAN communication (HS-CAN):	Via CAN communication (HS-CAN):
From the central electronic module (CEM) with information about which message must be displayed.	-

When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

• You smell fuel, burning insulation, or see smoke.

• Brakes feel soft, pull hard to one side, or make grinding noises.

• The engine overheats, stalls repeatedly, or misfires under load.

• You are missing required tools, torque specs, or safe lifting equipment.

• You are not confident in the next step or safety outcome.

Safety Warning

System overview: Signals

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When to See a Mechanic

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