VOLVO
CEM-8F18 - Xenon lamp left. Signal too high / Signal missing
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 central electronic module (CEM) has registered that the signal from the left xenon lamp is too high or missing altogether. The actuator motor is powered through the parking lamp circuit, so if the left parking lamp is not working the motor can lack voltage and the fault can appear.
Possible causes
- Signal wire short-circuited to voltage
- Open circuit in the signal wire
- The motor that moves the xenon lamp has seized
- Faulty or broken motor that moves the xenon lamp
What you can do
- 1Check that the left parking lamp works, because the actuator motor is powered through the parking lamp circuit
- 2Check the main fuse, the passenger compartment fuse and the parking lamp relay
- 3With the ignition on, switch between low and high beam to see whether the fault is permanent or intermittent
- 4Use a multimeter to check that the signal wire is continuous and has no contact with voltage when the ignition is off
- 5If the fault remains once the parking lamp and fuses are in order, have a workshop replace the left headlamp
Symptoms you may notice4
- The low beam is constantly lit
- The high beam is constantly lit
- Road surface lighting does not work
- Headlamp aim is wrong or the height adjustment does not work
What the fault can affect1
- The shortest beam range is used
General guidance for car owners. Diagnosis on the car can point to a different cause.