VOLVO
CEM-B109F09 - Average Quiescent Current. General Failure Information. Component Failures
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?
Information about the vehicle's power supply is stored in the central electronic module (CEM) and in the battery monitoring sensor (BMS). The fault shows that the average standby current draw of the vehicle is higher than normal, which may be due to a control module that does not sleep, an internal short in a module, or leakage current. The code alone does not indicate a fault in the CEM.
Possible causes
- One control module does not go to sleep mode
- One control module has an internal short circuit
- Leakage current in wiring or connectors somewhere in the car
What you can do
- 1Clear the code and check whether it returns after the car has been parked for a few days
- 2Check that the doors, hatches and bonnet are fully closed when the car is parked and that no lights stay on
- 3Check that the battery terminal clamps are tight and clean, and that the battery holds its charge
- 4Remove any extra equipment fitted afterwards and see whether the fault clears
- 5Have a workshop measure the standby current with measuring equipment and find which control module or circuit draws too much
Symptoms you may notice4
- The battery is dead
- The battery has low voltage
- The engine does not start or does not turn over
- The central locking does not work
General guidance for car owners. Diagnosis on the car can point to a different cause.