VOLVO
CEM-1C08 - Alternator control module (ACM). Mechanical fault
System
Central Electronic Module (CEM)
Volvo models this fault code applies to
Applies to the following models:
5 modelsS60 (2001–2009), S80 (1999–2006), V70 (2000–2008), V70 XC / XC70 (2001–2007), XC90 (2003–)
Show models by year and engine (16)
- Volvo S60 (2001–2009)2005All engines except: B5244S6
- Volvo S60 (2001–2009)2006All engines except: B5244S6, D5244T4, D5244T5, D5244T6, D5244T7
- Volvo S60 (2001–2009)2007–2009All engines except: D5244T4, D5244T5, D5244T7
- Volvo S80 (1999–2006)2005–2006
- Volvo V70 (2000–2008)2005All engines except: D5244T3
- Volvo V70 (2000–2008)2006All engines except: D5244T4, D5244T5, D5244T6, D5244T7
- Volvo V70 (2000–2008)2007All engines except: D5244T4, D5244T5, D5244T7
- Volvo V70 (2000–2008)2008All engines except: D5244T5, D5244T7
- Volvo V70 XC / XC70 (2001–2007)2005
- Volvo V70 XC / XC70 (2001–2007)2006All engines except: D5244T4
- Volvo V70 XC / XC70 (2001–2007)2007Engine B5254T2 only
- Volvo XC90 (2003–)2005All engines except: B8444S
- Volvo XC90 (2003–)2006All engines except: B8444S, D5244T4
- Volvo XC90 (2003–)2007–2012Engine B5254T2 only
- Volvo XC90 (2003–)2013–2014Engine B5254T9 only
- Volvo XC90 (2003–)2015
What does this fault code mean?
The generator control module (ACM) has told the CEM about a mechanical fault inside the generator. The fault may be in the drive belt or belt tensioner, in the freewheel, or in the generator itself. The battery may discharge and the starter motor may turn slowly.
Possible causes
- A damaged auxiliary drive belt and belt tensioner
- A damaged freewheel
- A damaged generator
What you can do
- 1Check that the drive belt is intact, not oily and not worn. Replace a damaged belt
- 2Check that the belt runs in line with the pulleys and that the tensioner keeps it tight
- 3Listen for unusual noise from the generator or belt with the engine idling
- 4Listen for unusual noise on start-up and when the engine slows. If it persists, replace the generator if you can, otherwise have a workshop do it
- 5After the work, clear the code and check that charging is normal and no noise is heard
Symptoms you may notice5
- The charging warning lamp lights with the engine running
- The battery discharges
- The starter motor turns slowly
- Noise from the generator or the drive belt
- The engine judders under acceleration
General guidance for car owners. Diagnosis on the car can point to a different cause.