VOLVO
CEM-1A63 - 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 modelsS60 (2001–2009), S80 (1999–2006), V70 (2000–2008), V70 XC / XC70 (2001–2007), XC90 (2003–)
What does this fault code mean?
The central electronic module (CEM) has lost communication with the accessory electronic module (AEM) and sets this code. The fault lies in the communication, not in the CEM, so the CEM should not be replaced. Accessories connected to the AEM do not work in the meantime.
Possible causes
- The AEM is not getting power
- The ground wire to the AEM is broken
- Contact resistance in the connections
- Broken CAN wiring to the AEM
- Wrong AEM for this car, for example a used module with different software or hardware
- A common CAN network fault if several communication faults are stored at the same time
What you can do
- 1Check the AEM fuse. If it has blown, replace it once. If it blows again, use a multimeter to check the wire after it has no contact with ground.
- 2Check that the fuse contacts are clean and firmly fitted, and that the connectors to the AEM are seated and not corroded
- 3Use a multimeter to check that the wire between the AEM and its ground point has no break or short to ground
- 4If the fault remains, read the module ID with a diagnostic tool
- 5After the work, clear the code and check that the accessories work
Symptoms you may notice1
- Accessories wired to the control module stop working
General guidance for car owners. Diagnosis on the car can point to a different cause.