VOLVO
CEM-8B08 - Light switch module (LSM). Signal too low
System
Central Electronic Module (CEM)
Volvo models this fault code applies to
Applies to the following models:
5 modelsC30 (2007–2013), C30 Electric (2011–2013), C70 (2006–2013), S40 (2004–2013), V50 (2004–2013)
What does this fault code mean?
The CEM feeds the LSM backlighting directly from one output. The CEM has registered that the signal returned does not match the signal sent out. The cause is a background lighting signal wire shorted to ground, and as a result the instrument panel lighting does not work.
Possible causes
- The background lighting signal wire to the light switch module (LSM) is short-circuited to ground
What you can do
- 1Check whether the lighting in the light switch and the instrument panel is completely off or only partly off
- 2With the ignition off, check that the connector at the light switch is clean and firmly fitted
- 3Use a multimeter to check that the signal wire has no contact with ground (the body) when the connector is unplugged
- 4Look for chafing and pinched spots along the wiring to the light switch
- 5If the fault remains, have a workshop check the signal wire and the module
Symptoms you may notice1
- The instrument panel lighting does not work
General guidance for car owners. Diagnosis on the car can point to a different cause.