VOLVO
CEM-1E04 - Communication with the lamp switch module. Signal missing. Intermittent fault
System
Central Electronic Module (CEM)
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 CEM lost communication with the light switch module (LSM) shortly after the ignition was switched on. The fault is intermittent, so it may not be present right now. The beam height control and the light switch may then stop working.
Possible causes
- A broken or shorted wire between the light switch and the CEM
- A defective communication unit in the light switch
- A defective communication unit in the CEM
What you can do
- 1Check that the light switch responds: switch the headlights on and off and see whether they react to the controls
- 2Check that the connectors in the cable between the light switch and the CEM are seated and not chafed or corroded
- 3Use a multimeter to check that the cable to the light switch has no break or short to ground
- 4With a diagnostic tool, read the fault codes and see whether communication with the light switch works
- 5After the work, clear the code and check that the beam height control works
Symptoms you may notice2
- The beam height control does not work
- The light switch does not work
General guidance for car owners. Diagnosis on the car can point to a different cause.