VOLVO
CEM-8F12 - Beam setting control. Signal too low. Intermittent fault
System
Central Electronic Module (CEM)
Volvo models this fault code applies to
This fault code has different meanings depending on model, model year or engine. Select the meaning that applies to your car.
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 fault is intermittent: the signal from the beam height control was too low on one occasion but is no longer present. The central electronic module (CEM) compares the signal with its own voltage and records the fault when the difference is too large. A connection that briefly loses contact can cause this, so the low beam adjustment can stop working for a while.
Possible causes
- Defective beam height control actuator
- Poor contact in the connector
- Open circuit in the wire or short-circuit to ground
What you can do
- 1Clear the code and check whether it returns; a single intermittent fault can be a temporary disturbance
- 2With the ignition off, gently move the wiring and connectors to find any play
- 3Check that the connectors are clean, dry and firmly seated
- 4Use a multimeter to check that the wire has no break and no contact with ground (the body)
- 5If you have a diagnostic tool, run the actuator motor and listen for it starting without jerking
- 6If the fault returns although the connectors and wire are in order, have a workshop replace the actuator motor
Symptoms you may notice1
- The beam height adjustment does not work
General guidance for car owners. Diagnosis on the car can point to a different cause.