VOLVO
ECM-830D - Alternator control module (ACM). Signal too high
System
Engine Control Module (ECM)
Volvo models this fault code applies to
Applies to the following models:
4 modelsC30 (2007–2013), C70 (2006–2013), S40 (2004–2013), V50 (2004–2013)
Show models by year and engine (9)
- Volvo C30 (2007–2013)2007Engine B5254T3 only
- Volvo C30 (2007–2013)2008–2013Engine B5254T7 only
- Volvo C70 (2006–2013)2006–2007Engine B5254T3 only
- Volvo C70 (2006–2013)2008–2013Engine B5254T7 only
- Volvo S40 (2004–2013)2005–2007Engine B5254T3 only
- Volvo S40 (2004–2013)2008Engine B5254T3, B5254T7 only
- Volvo S40 (2004–2013)2009–2012Engine B5254T7 only
- Volvo V50 (2004–2013)2005–2007Engine B5254T3 only
- Volvo V50 (2004–2013)2008–2012Engine B5254T7 only
What does this fault code mean?
The generator's control module (ACM) reports an electrical fault in the generator to the engine control module, and that is what sets the code. It may be caused by worn brushes, a damaged generator control module or a damaged generator, or by a battery charger with too high a charge voltage having been connected. The fault applies to the C30, C70 (06-), S40 (04-) and V50.
Possible causes
- A battery charger with too high a charge voltage was connected earlier
- Worn brushes (carbon)
- Damaged generator control module (charge regulator)
- Damaged generator
What you can do
- 1Read and note the code, clear it and road test to see whether it returns
- 2Start the engine and read the battery voltage, if you have a diagnostic tool
- 3Switch on a few high-current consumers and see whether the battery voltage stays steady
- 4Listen for unusual noise from the generator and check whether the generator not charging lamp comes on while the engine runs
- 5Have a workshop replace the generator or its control module if the brushes or slip rings are worn or if the fault remains
Symptoms you may notice5
- The generator warning lamp (not charging) comes on while the engine runs
- The battery discharges
- Low rotation speed in the starter motor
- The electrolyte in the battery boils when the engine runs
- The headlamp bulb blows
General guidance for car owners. Diagnosis on the car can point to a different cause.