Checking The Power Supply And Ground For The Upper Electronic Module (UEM)

Check that the fuse in the fusebox in the passenger compartment for the upper electronic module (UEM) is intact.

NOTE:

If the fuse has blown, check the circuit after the fuse before replacing the fuse. Check for a short-circuit to ground. Then replace the fuse.

Check the connectors and wiring for the upper electronic module (UEM) and the battery connection. Check for contact resistance and oxidation. Check for loose connections.

Check the cable between the control module and ground. Check for an open-circuit. Check for a short-circuit to supply voltage.

Remedy as necessary.

Other information:

To access or replace the fuses, see FUSEBOX, PASSENGER COMPARTMENT, REPLACING
To access or replace the upper electronic module (UEM), see UPPER ELECTRONIC MODULE (UEM)/REARVIEW MIRROR, REPLACING
To connect the breakout box, see CONNECTING THE BREAKOUT BOX
For information about signals and connectors, see SIGNAL DESCRIPTION, UPPER ELECTRONIC MODULE (UEM)
For information about checking wiring and terminals, see CHECKING WIRING AND TERMINALS. PERMANENT FAULT .

Fig 1: Breakout Box

Courtesy of VOLVO CARS CORPORATION

Fig 2: Identifying Ohm Meter

Courtesy of VOLVO CARS CORPORATION

Was a fault detected?

YES
Refer to CHECKING THE FUNCTION OF THE UPPER ELECTRONIC MODULE (UEM)
NO
Refer to SIGNAL MISSING