VOLVO
CEM-8D0A - 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 emergency brake light directly from one output. The code is set when a faulty signal lasts for a while with the brake light activated. The cause is a voltage supply wire shorted to ground.
Possible causes
- The voltage supply wire is short-circuited to ground
What you can do
- 1Press the brake with the ignition on. If the left light stays dark the fault is likely permanent; if it worked before, it is intermittent
- 2Check that the brake light fuse is intact
- 3With the ignition off, use a multimeter to check that the voltage supply wire has no contact with ground (the body)
- 4Look for chafing and pinched spots where the wire runs in the rear wiring harness
- 5If the fault returns, have a workshop with diagnostic equipment check the circuit
Symptoms you may notice2
- The left brake light and tail light do not work
- The lights stay constantly on
General guidance for car owners. Diagnosis on the car can point to a different cause.