VOLVO
UEM-0004 - Siren. Communication fault
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) sends requests to the siren and gets no reply. The code is set when the siren does not answer repeated requests, which is read as a communication fault. The alarm then does not work as it should.
Possible causes
- Break in the serial cable between the UEM, the siren and the sun roof
- The serial cable is short-circuited to ground
- The serial cable is short-circuited to voltage
- Defective siren
What you can do
- 1Check that the fuses in the fuse box in the passenger compartment are intact.
- 2Read off the code, clear it and test the alarm to see whether the fault returns.
- 3Look for loose connectors and corrosion at the siren and at the upper electronic module.
- 4Look for damage on the cable harness to the siren and the sun roof.
- 5Use a multimeter to check that the wire to the siren is not broken and has no contact with ground or voltage.
- 6If no fault is found, have a workshop try a new siren.
Symptoms you may notice5
- The siren does not work
- The alarm does not work at all
- The alarm does not arm, and there is no visible indication in the car
- The alarm does not sound, and neither an audible nor a visible signal appears
- Warning symbol and text message in the display
General guidance for car owners. Diagnosis on the car can point to a different cause.