VOLVO
CEM-8D05 - Right-hand stop lamp. 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 right-hand brake light straight from one output. It has registered a signal from that output that is too low, which points to the signal wire to the right-hand brake light being shorted to ground.
Possible causes
- The signal wire to the right-hand brake light is shorted to ground
What you can do
- 1Press the brake pedal with the ignition on. If the right brake light stays off the fault is likely permanent; if it works but the code was stored earlier, it is intermittent
- 2Check the brake light fuse and that the bulb sits properly in its holder
- 3With the ignition off and the lamp connector unplugged, use a multimeter to check that the wire has no contact with ground (the body)
- 4Look for chafing and pinched spots along the wire to the right brake light, especially where it runs through the rear wiring harness
- 5If the fault remains, have a workshop with diagnostic equipment check the circuit and the module
- 6Deal with this promptly, since drivers behind you cannot see when you brake
Symptoms you may notice1
- The right-hand brake light does not come on when the pedal is pressed
General guidance for car owners. Diagnosis on the car can point to a different cause.