2004 Volvo V70 R, StandardFACTORY OEM SERVICE PROCEDURE

Control module

Fig 1: Active On Demand Coupling Control Module
GLL106598Courtesy of VOLVO CARS OF NORTH AMERICA.

The differential electronic module (DEM) is secured directly to the coupling unit housing and forms a single unit with the axial solenoid. The axial solenoid controls the control valve.

The differential electronic module (DEM) receives signals from the engine control module (ECM), the central electronic module (CEM) and the brake control module (BCM) via the high speed side of the control area network (CAN). The differential electronic module (DEM) uses these signals to determine the oil pressure required for the multi-plate clutch in the coupling unit. The oil pressure for the multi-plate clutch determines the amount of torque which can be transferred to the rear wheels.

Four wheel drive is not available if there is a fault in the differential electronic module (DEM).

Factory Service Tools

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When to See a Mechanic

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

  • β€’ You smell fuel, burning insulation, or see smoke.
  • β€’ Brakes feel soft, pull hard to one side, or make grinding noises.
  • β€’ The engine overheats, stalls repeatedly, or misfires under load.
  • β€’ You are missing required tools, torque specs, or safe lifting equipment.
  • β€’ You are not confident in the next step or safety outcome.

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