Intermittent fault

Check control unit and wire connector (54/3R, 54/10 or 54/11 and 3/126 or 3/127) for contact resistance and oxidation as described in Contact resistance and oxidation , and for a loose contact as described in Loose connections (terminals) .

Check that main fuse (11A/2) in engine compartment relay/fuse box is correctly installed.

If control unit is on the left side, check that interior fuse (11C/35) in interior fuse box is correctly installed.

If control unit is on the right side, check that interior fuse (11C/36) in interior fuse box is correctly installed.

Check the wire between control unit 12B and the ignition lock for an intermittent short circuit to ground as described in Short-circuit to ground, intermittent faults , and for an intermittent open circuit as described in Open-circuit, intermittent faults .

Check the wire between control unit 9B and ground: Check front left or right seat support for an intermittent short circuit to ground as described in Short-circuit to ground, intermittent faults , and for an intermittent open circuit as described in Open-circuit, intermittent faults .

Additional information:

With ignition off, voltage between control unit 12B and ground should be battery voltage.
To connect the test box, see Connecting the breakout box .
For information on signals and additional values, see Signal specification .
To access the door control unit, see Lock mechanism front side door, replacing .

Fig 1: Identifying Connector Terminals

Courtesy of VOLVO CARS OF NORTH AMERICA.

Fig 2: Identifying Ohm Meter

Courtesy of VOLVO CARS OF NORTH AMERICA.

Fig 3: Identifying Passenger Compartment Fusebox

Courtesy of VOLVO CARS OF NORTH AMERICA.