VOLVO
CEM-B102483 - Start control unit. Bus Signal / Message Failures. Value of signal protection calculation incorrect
System
Central Electronic Module (CEM)
Volvo models this fault code applies to
Applies to the following models:
2 modelsV40 (2013–), V40 Cross Country (2013–)
Show models by year and engine (2)
What does this fault code mean?
The central electronic module (CEM) and the ignition lock antenna unit (IAU) share a LIN bus. The fault code is stored when the message from the left steering wheel buttons (SWSL) becomes incorrect on the bus, which can disturb starting and the function of the ignition lock.
Possible causes
- Contact resistance, oxidation or loose connections in connectors or joints
- Damaged ignition lock antenna unit (IAU)
What you can do
- 1Check the connectors at the left steering wheel buttons and at the antenna unit for oxidation and loose connections, and gently move the wiring with the ignition on
- 2Check that the left-hand steering wheel buttons do not stick or are damaged
- 3With a diagnostic tool, check for another fault code ending in 86 or 88 in the same control unit; it points to the bus and should be dealt with first
- 4Clear the fault code and road test. If it returns, have a workshop check the antenna unit
Symptoms you may notice3
- The starter motor does not turn over, and there is no click when starting is attempted
- The engine does not start, or starts only unreliably
- Amber warning symbol and text message in the display
General guidance for car owners. Diagnosis on the car can point to a different cause.