VOLVO
CEM-8D03 - High level stop lamp. Signal too high
System
Central Electronic Module (CEM)
Volvo models this fault code applies to
This fault code has different meanings depending on model, model year or engine. Select the meaning that applies to your car.
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 central electronic module (CEM) registers a signal to the high-mounted brake light that is too high. This points to the signal wire to the brake light being shorted to battery voltage, and the brake light then stays on constantly.
Possible causes
- The signal wire to the high-mounted brake light is short-circuited to battery voltage
What you can do
- 1Press the brake pedal with the ignition on and then release it. If the high-mounted light stays on even when the pedal is released, the signal wire is the likely cause
- 2With the ignition off, use a multimeter to check that the wire to the high-mounted brake light has no voltage
- 3Look for chafing and pinched spots along the wire to the high-mounted brake light
- 4Have a workshop check the circuit and replace the brake light if it is defective
Symptoms you may notice1
- The brake light stays on constantly
General guidance for car owners. Diagnosis on the car can point to a different cause.