Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Central electronic module (CEM)
The central electronic module (CEM) (4/56) is the master unit for the immobilizer function. The central electronic module (CEM) and engine control module (ECM) are linked to each other through codes. The central electronic module (CEM) is also programmed with a code for each ignition key for the vehicle.
The central electronic module (CEM) transmits commands and signals to the other units in the system. The central electronic module (CEM) also approves the identity of the key. The key is checked via the antenna ring. The antenna ring is installed around the ignition switch. There is a transponder (communication circuit) in the ignition key. The identification code of the transponder is unique. The code must be learned by the central electronic module (CEM) before the key can be used to start the vehicle. This code is learned during at the factory. New keys can be added afterwards.
The central electronic module (CEM) checks the relay for the starter motor.
For further information about the central electronic module (CEM), see VIDA Design and Function, central electronic module (CEM).
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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.
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