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

Rear electronic module (REM) (4/58):

Input signals	Output signals
Directly connected:	Directly connected:
Glass breakage sensors (7/135-7/137) (V70/XC70 only). Switch in lock unit (3/74) for indicating open driver's door. Switch in lock unit (3/75) for indicating open passenger door. Switch in lock unit (3/76) for indicating open door, left rear. Switch in lock unit (3/77) for indicating open door, right rear. Switch in hood lock (3/62) for indicating open hood. Switch in lock unit (3/78) for indicating open trunk lid/tailgate.	Alarm LED (7/12) for indicating alarm status. Inclination sensor module (ISM) (7/100), power supply.
Via serial communication:	Via serial communication:
Inclination sensor module (ISM) (7/100) for information about vehicle position.	Inclination sensor module (ISM) (7/100) for status request.
Via CAN communication (LS-CAN):	Via CAN communication (LS-CAN):
Reduced alarm switch (3/174) via the climate control module (CCM) (3/112) for deactivation of the inclination sensor module (ISM), the mass movement sensor module (MMS) and deadlock mode. Upper electronic module (UEM) (4/70) for signals from the mass movement sensor module (MMS), siren (SCM) and commands from the remote control.	The driver information module (DIM) (5/1) for information about which message is to be displayed. Upper electronic module (UEM) (4/70) for siren (SCM) activation. Central electronic module (CEM) (4/56) for activating direction indicator lamps when the alarm is triggered and the horn during triggered panic function.

Upper electronic module (UEM) (4/70):

Input signals	Output signals
Directly connected:	Directly connected:
-	For S60/S80/V70/XC70: Mass movement sensor module (MMS) (7/122), power supply. For XC90: Mass movement sensor module (MMS) (7/158), rear sensor and mass movement sensor module (MMS) (7/122), front sensor, power supply. The sensors are connected in parallel.
Via serial communication:	Via serial communication:
For S60/S80/V70/XC70: Mass movement sensor module (MMS) (7/122). For XC90: Mass movement sensor module (MMS) (7/158), rear sensor and mass movement sensor module (MMS) (7/122), front sensor. The sensors are connected in parallel. Communication with the siren (SCM) (16/35).	For S60/S80/V70/XC70: Mass movement sensor module (MMS) (7/122). For XC90: Mass movement sensor module (MMS) (7/158), rear sensor and mass movement sensor module (MMS) (7/122), front sensor. The sensors are connected in parallel. Communication with the siren (SCM) (16/35).
Via CAN communication (LS-CAN):	Via CAN communication (LS-CAN):
Rear electronic module (REM) (4/58) with request for function activation.	Rear electronic module (REM) (4/58) with command for siren (SCM) activation.

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

Use the Manual With the Right Hardware

When to See a Mechanic

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