The chart below summarizes the input signals to and output signals from the differential electronic module (DEM). The following illustration displays the same information with the Volvo component designations.

Input signals	Output signals
Directly connected:	Directly connected: (power supply unless otherwise stated)
Oil pressure and temperature sensor .	Electrical feed pump Axial solenoid - pulse width modulated (PWM) signal.
Via Controller Area Network (CAN) communication:	Via Controller Area Network (CAN) communication:
Central electronic module (CEM) (4/56), status of the parking brake switch, ignition key position and back-up (reverse) signal Brake control module (BCM) (4/16), the wheel speed from the wheel rotation sensor and the status signal (to open the coupling during stability control) Engine control module (ECM) (4/46), provides data about engine speed (RPM), torque, accelerator pedal (AP) position and the status of the stop lamp switch.	Brake control module (BCM) (4/16), status of the coupling.

Fig 1: Input Signals To And Output Signals From Differential Electronic Module

Courtesy of VOLVO CARS OF NORTH AMERICA.

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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