VOLVO
CEM-B100B86 - External receiver. Bus Signal / Message Failures. Signal invalid
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) communicates with the remote receiver (RRX) every time the ignition is switched on. The fault code is stored when that communication is incorrect. The remote control may then stop working and the tyre pressure monitoring may show faults.
Possible causes
- Contact resistance, oxidation or loose connections in connectors or joints
- Internal fault in the remote receiver (RRX)
What you can do
- 1Check the connectors and wiring to the remote receiver for oxidation and loose connections, and gently move the wiring with the ignition on
- 2Test the remote control by locking and unlocking the car. If it still fails after the connectors are checked, the fault is probably still present
- 3With the ignition off, use a multimeter to check whether the wires to the remote receiver have contact with earth or voltage
- 4Clear the fault code and road test to see whether it returns
- 5If the fault remains, have a workshop check the communication and the remote receiver, since this needs diagnostic equipment
Symptoms you may notice2
- The remote control does not work
- Tyre pressure monitoring warning lights and chimes do not show the correct status
General guidance for car owners. Diagnosis on the car can point to a different cause.