VOLVO
CEM-DE52 - Communication with the Accessory Electronic Module (AEM). Signal missing
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 has lost contact with the accessory electronic module (AEM), so accessories controlled by the module do not work. The fault is set when communication on the low speed network breaks down. It is most often a matter of supply, earth or a connector at the AEM.
Possible causes
- No supply to the AEM
- Open circuit in the earth wire to the AEM
- Contact resistance in the connections
- Open circuit in the LS-CAN wires to the AEM
- The AEM does not suit the car, for example a used module with other software or hardware
What you can do
- 1Try the accessories connected to the module, for example the luggage compartment power socket, and note which ones do not work
- 2Check the AEM fuse in the engine bay fuse box and the luggage compartment socket fuse in the CEM. If one has blown, check its circuit for a short to earth
- 3Use a multimeter to check that the wire between the AEM and the earth point has no break and is not shorted to earth or supply voltage
- 4Check the AEM earth point for loose contact and oxidation
- 5With a diagnostic tool, read the AEM ID. If it reads, the CAN communication is probably fine and the fault may be intermittent
- 6The CEM should not be replaced until the communication with the AEM has been checked
Symptoms you may notice1
- Accessories connected to the module do not work
General guidance for car owners. Diagnosis on the car can point to a different cause.