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
The central electronic module (4/56) is the main control module for alarm functionality. The central electronic module determines how the alarm should be activated, deactivated or deployed by receiving information on the Controller Area Network (CAN) from other control modules and via the directly connected signal cables from the components.
Signal cables are directly connected to the central electronic module from:
- Switch in the lock units in all doors (3/74-77), open/closed
- Switch in the lock units in the rear side doors (3/76-77), locked / unlocked
- Switch in the lock unit trunk lid (3/78), open/closed. (S60/S80)
- Switch in the lock unit tailgate (3/78), open/closed. (V70/V70XC). In certain versions the signal is in series with the resistive wire in the rear side window. See appropriate SYSTEM WIRING DIAGRAM article
- Switch hood (3/62), open/closed
- Resistive wire (7/135-137), broken/unbroken (only V70/V70XC). Protects rear side windows, on certain versions this includes the rear windshield, see appropriate SYSTEM WIRING DIAGRAM article.
The central electronic module is controlled via a direct cable:
- All turn signal lamps.
For information received and transmitted via the controller area network for alarm functionality see the relevant control module as follows.
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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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