VOLVO
UEM-003A - Extended X supply (EXT_X). Signal too low
System
Upper Electronic Module (UEM)
Volvo models this fault code applies to
Applies to the following models:
5 modelsS60 (2001–2009), S80 (1999–2006), V70 (2000–2008), V70 XC / XC70 (2001–2007), XC90 (2003–)
What does this fault code mean?
The upper electronic module (UEM) feeds several functions through the extended X supply (EXT X): the sun roof logic, the sun visor mirror lamps, the rain sensor, and the buttons for the roof lighting along with some button lighting. The code is set when the feed to these functions is too low, because it is shorted to ground. Several functions then stop working.
Possible causes
- The feed to the sun roof, the sun visor mirror lamps, the rain sensor, the roof lighting buttons and some button lighting is short-circuited to ground
What you can do
- 1Check that the fuses for the sun roof and the interior lighting are intact.
- 2If all of these functions stop working at the same time, the cable from the upper electronic module to the junction point, or the wiring from there, may be shorted to ground.
- 3Use a multimeter to check that the wires have no contact with ground (the bodywork).
- 4Check that the rain sensor wire is not pinched under the foot of the interior rear view mirror, and unplug its connector to inspect it separately.
- 5If the fault remains, have a workshop check the wiring.
Symptoms you may notice3
- The electric sun roof does not work
- The interior lighting does not work
- The rain sensor does not work
What the fault can affect1
- The sun roof, sun visor mirror lamps, roof lighting buttons and some button lighting are switched off
General guidance for car owners. Diagnosis on the car can point to a different cause.