VOLVO
CEM-B124912 - Start Button Illumination. General Electrical Failures. Circuit short to battery
System
Central Electronic Module (CEM)
Volvo models this fault code applies to
Applies to the following models:
9 modelsS60 (2011–), S80 (2007–), V40 (2013–), V40 Cross Country (2013–), V60 (2011–), V60 Cross Country (2015–), V70 (2008–), XC60 (2009–), XC70 (2008–)
What does this fault code mean?
The CEM monitors the signal to the illumination in the start button. The fault is stored when the signal from the output is too high. The causes are poor contact in the connections or a signal wire that is short-circuited to voltage.
Possible causes
- Contact resistance, oxidation or poor contact in the connections
- The signal wire is short-circuited to voltage
What you can do
- 1Check that the fuses are intact
- 2Press the start button and see whether the illumination lights, then clear the fault code and road test
- 3Check the connectors at the start button and at the CEM, and clean or press in any that are loose or oxidised
- 4Check the signal wire to the start button for chafing and pinch damage
- 5With the connectors disconnected, use a multimeter to check that the signal wire is not short-circuited to voltage
- 6If the fault returns, have a workshop with diagnostic equipment fault-trace the control module and the wiring
Symptoms you may notice1
- The illumination in the start button does not work
What the fault can affect3
- The illumination switches off during the driving cycle in which the fault is detected
- If the fault remains, the illumination is switched off permanently after 100 driving cycles where the fault was detected
- Erasing the fault codes and starting a new driving cycle resets the output
General guidance for car owners. Diagnosis on the car can point to a different cause.