VOLVO
CEM-8A25 - Gas discharge lamp module (GDL) right-hand. Faulty signal
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 right-hand gas discharge lamp module (GDL) reports an internal fault to the central electronic module (CEM). Although the code is named faulty signal, the cause can lie in the module, in the lamp housing or in the signal wiring between them. The lamp and the wiring are therefore checked first.
Possible causes
- The right-hand gas discharge lamp module (GDL) is faulty
- The right-hand lamp housing is faulty
- Open circuit in the signal wire between the right-hand lamp housing and the gas discharge lamp module
- The signal wire between the lamp housing and the module is short-circuited to battery voltage
- The signal wire between the lamp housing and the module is short-circuited to ground
What you can do
- 1Switch on the low beam. If the right lamp stays dark, the fault is likely permanent; if it lights but the code was stored earlier, it is intermittent
- 2Switch the ignition off and unplug the connectors at the right headlamp. Check that they are clean, firmly fitted and not damaged or corroded
- 3Use a multimeter to check that the signal wires between the headlamp and the module are not broken and have no contact with ground or battery voltage
- 4After a recent refit, make sure the igniter sits properly. It carries high voltage, so leave other work to a workshop
- 5If the fault remains, have a workshop replace the module. After replacement the car data must be programmed in and the position sensors recalibrated
Symptoms you may notice1
- The right low beam does not work
General guidance for car owners. Diagnosis on the car can point to a different cause.