VOLVO
CEM-U012100 - Lost Communication With Brake Control Module. General Failure Information. No sub type information
System
Central Electronic Module (CEM)
Volvo models this fault code applies to
Applies to the following models:
9 modelsS60 (2011–), S80 (2007–), V40 (2013–), V40 Cross Country (2013–), V60 (2011–), V60 Cross Country (2015–), V70 (2008–), XC60 (2009–), XC70 (2008–)
What does this fault code mean?
The fault code means that the control module storing the fault does not get a link to the brake control module (BCM), or the link is disturbed. The BCM handles among other things the ABS function, and when the link is lost the ABS may stop working. The fault can also show up as the engine not starting.
Possible causes
- No power reaching the brake control module (BCM)
- Broken ground wire to the brake control module
- Poor contact in the connections
- Open or shorted CAN wiring
- A brake control module not intended for the car, such as a used unit with other software or hardware
What you can do
- 1Switch the ignition off and check the supply wires from the battery to the BCM for breaks, loose contact and oxidation
- 2Check the ground wires between the BCM and the car body for breaks, loose connections and oxidation
- 3Check the CAN wires for chafing and breaks, especially where the wiring moves
- 4With a diagnostic tool, read whether the BCM responds and compare with what the checks above showed
- 5Safety: the ABS braking system is affected. Have a workshop check the ABS system with diagnostic equipment. Replace the CEM only if testing has shown it is damaged
Symptoms you may notice4
- ABS warning lamp comes on
- ABS does not work or engages unexpectedly
- Starter does not turn over or the engine will not start
- Message in the information display
What the fault can affect1
- No ABS function
General guidance for car owners. Diagnosis on the car can point to a different cause.