VOLVO
CEM-B102487 - Start control unit. Component Failures. Component internal failure
System
Central Electronic Module (CEM)
Volvo models this fault code applies to
This fault code has different meanings depending on model, model year or engine. Select the meaning that applies to your car.
Applies to the following models:
7 modelsS60 (2011–), S80 (2007–), V60 (2011–), V60 Cross Country (2015–), V70 (2008–), XC60 (2009–), XC70 (2008–)
What does this fault code mean?
The central electronic module (CEM) has stopped getting replies from the ignition lock control unit (SCU) and also checks the antenna unit (IAU). The fault code is stored when communication is missing, and the starter motor then cannot be turned over. The fault may be temporary or permanent.
Possible causes
- Supply voltage to the ignition lock control unit is broken
- Earth wire to the ignition lock control unit is broken
- Signal wire to the ignition lock control unit is broken
What you can do
- 1Check the fuse for the ignition lock control unit and replace it if it has blown
- 2Check the wires and connectors between the ignition lock control unit and the CEM for breaks, chafing and loose connections
- 3With the ignition off, use a multimeter to check whether the earth wire to the control unit is broken, and whether it has voltage to earth
- 4If the fault is temporary, for example at start-up, clearing the fault code and taking a short drive may be enough. Follow up in case it comes back
- 5If the fault returns, have a workshop read the serial number of the control unit and replace it if needed
Symptoms you may notice3
- The starter motor does not turn over
- A message appears in the information display
- The engine does not start, and starting may be unreliable, at times or all the time
General guidance for car owners. Diagnosis on the car can point to a different cause.