VOLVO
CEM-8D09 - Brake lamp left. Faulty signal
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 supplies the left brake light, which is the emergency brake light, directly from its own output. The code is set when a faulty signal lasts for a while with the brake light not activated. The fault can lie in a poor connection, a break in the supply wire, or a supply that is in contact with battery voltage.
Possible causes
- Contact resistance, oxidation or a loose connection at the connectors
- Open circuit in the voltage supply wire
- The voltage supply is short-circuited to battery voltage
What you can do
- 1Check the fuses for the tail and brake lights. They should be intact
- 2Switch on the tail lights and press the brake with the ignition on. Check that the left lamp lights and goes out as it should
- 3Check the connectors at the lamp housing and in the rear wiring for oxidation, looseness and contact resistance
- 4With the ignition off, use a multimeter to check that the supply wire is unbroken
- 5If the fault returns, have a workshop with diagnostic equipment check the voltage supply
Symptoms you may notice2
- The tail light or brake light does not work
- The tail light or brake light stays lit constantly
General guidance for car owners. Diagnosis on the car can point to a different cause.