Checking the power supply and ground for the differential electronic module (DEM)

Fig 1: Identifying Ignition OFF

Courtesy of VOLVO CARS OF NORTH AMERICA.

• Ignition off.

  Check that the fuse by the main fuse for the battery for the differential electronic module (DEM). Check that the fuse in the fuse box in the cargo compartment for the rear electronic module is intact.

  Check the cable between the fuse and the power supply relay for the differential electronic module (DEM). Check for an open-circuit. Check for a short-circuit to ground. Check for a short-circuit to supply voltage.

  Check the cable between the power supply relay for the differential electronic module (DEM) and the control module. Check for an open-circuit. Check for a short-circuit to ground. Check for a short-circuit to supply voltage.

  Check the connectors and wiring for the differential electronic module (DEM) and the battery terminal. Check for contact resistance and oxidation. Check for loose connections.

  If necessary, check the function of the power supply relay by moving it to another position.

  Check the cable between the ground terminal and the differential electronic module (DEM). Check for an open-circuit. Check for a short-circuit to ground. Check for a short-circuit to supply voltage.

  Check the ground terminal for the differential electronic module (DEM). Check for contact resistance and oxidation.

  Other information: 

  • To access the differential electronic module (DEM), see Differential electronic module (DEM), replacement
  • See Checking wiring and terminals .
  Fig 2: Identifying Ohmmeter

  Courtesy of VOLVO CARS OF NORTH AMERICA.
  Fig 3: Identifying Active On Demand Coupling Control Module

  Courtesy of VOLVO CARS OF NORTH AMERICA.

Was a fault detected? 

• YES 

  Refer to Checking the differential electronic module (DEM) 

• NO 

  Refer to Checking communication with the differential electronic module (DEM)