VOLVO
CEM-8A40 - Gas discharge lamp module (GDL) left-hand. Calibration fault
System
Central Electronic Module (CEM)
Volvo models this fault code applies to
Applies to the following models:
4 modelsC30 (2007–2013), C70 (2006–2013), S40 (2004–2013), V50 (2004–2013)
Show models by year and engine (4)
What does this fault code mean?
The position sensors for the left-hand gas discharge lamp are not calibrated, and the module (GDL) reports this to the central electronic module (CEM). Without calibration, automatic headlamp range control does not work. Calibration is a workshop job.
Possible causes
- The position sensors are not calibrated
What you can do
- 1Check whether anything has recently been done to the left headlamp, such as removing or replacing the lamp, since the calibration may then have been lost
- 2Check that the position sensors are fitted correctly
- 3Have a workshop calibrate the position sensors with the car unladen and on a level surface
Symptoms you may notice1
- Automatic headlamp range control does not work
What the fault can affect1
- The shortest headlamp range is used
General guidance for car owners. Diagnosis on the car can point to a different cause.