VOLVO
CEM-B109A09 - Quiescent Current in Normal Mode. 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 vehicle's standby power consumption is higher than normal, which can be caused by a control module that does not go to sleep, an internal short in a module, or a leakage current. The code alone does not point to a fault in the CEM, so the module should not be replaced unless fault tracing identifies it.
Possible causes
- One of the control modules does not go to sleep mode
- One of the control modules 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 locked and left standing overnight
- 2Check that the cabin, luggage and other lighting is off when the car is parked
- 3Check the battery condition and that the terminal clamps are tight and clean
- 4Remove any extra equipment fitted afterwards, such as an alarm or charger, and see whether the fault clears
- 5If the fault returns, have a workshop measure the standby current and find which control module or circuit draws too much
Symptoms you may notice5
- The engine does not start or does not turn over
- No clicking sound when trying to start
- The battery is dead or has low voltage
- Warning symbol and text message about a low battery in the display
- The central locking does not work
General guidance for car owners. Diagnosis on the car can point to a different cause.