VOLVO
CEM-1A59 - Communication with the audio module (AUM). 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 audio module (AUM) and sets this code. The fault lies in the communication, not in the CEM, so the CEM should not be replaced. Radio controls on the steering wheel and the remote control may stop working, and the rheostat function of the audio system is lost.
Possible causes
- The audio module is not getting power
- The ground wire to the audio module is broken
- Contact resistance in the connections
- Broken CAN wiring to the audio module
- Wrong audio module 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
- 1Switch on the radio or play a CD and check that sound comes from the speakers
- 2Check the main unit 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.
- 3Check that the connector to the main unit is seated and not corroded, chafed or damaged. Check that the ground wire is tight and clean
- 4Use a multimeter to check that the wire to the audio module is not broken. If the fault remains, read the module ID with a diagnostic tool
- 5After the work, clear the code and check that the steering wheel buttons work
Symptoms you may notice3
- The rheostat function on the audio system does not work
- The audio system cannot be operated with the remote control
- Radio controls on the steering wheel do not work
General guidance for car owners. Diagnosis on the car can point to a different cause.