VOLVO
CEM-8D10 - Brake light switch Compare error
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 compares the brake light switch signal with what is sent on the CAN network. If they do not match, the code is set. The cause is an open circuit in the signal wire from the brake light switch. The fault gives no noticeable symptoms for the driver.
Possible causes
- Open circuit in the signal wire from the brake light switch
What you can do
- 1If the brake lights work and no other codes apply to them, it may be enough to clear the code and see whether it returns
- 2If you have a diagnostic tool: read the brake switch signal as live data while you press and release the brake
- 3With the ignition off, use a multimeter to check that the signal wire from the brake light switch is unbroken
- 4Check the connector at the brake light switch for oxidation and loose connections
- 5If the fault returns, have a workshop with diagnostic equipment check the wire and the brake light switch
Symptoms you may notice1
- No noticeable symptoms for the driver
General guidance for car owners. Diagnosis on the car can point to a different cause.