VOLVO
ECM-A10D - Alternator control module (ACM). Faulty communication
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 (6)
- Volvo C30 (2007–2013)2007–2011Engine B5244S4 only
- Volvo C70 (2006–2013)2006All engines except: B5254T3
- Volvo C70 (2006–2013)2007–2010Engine B5244S4, B5244S5 only
- Volvo C70 (2006–2013)2011Engine B5244S4 only
- Volvo S40 (2004–2013)2005–2010Engine B5244S4, B5244S5, B5244S7 only
- Volvo V50 (2004–2013)2005–2010Engine B5244S4, B5244S5, B5244S7 only
What does this fault code mean?
The alternator control module (ACM) sends the engine control module information about the alternator's condition over the LIN network. The code is set when the alternator reports an electrical fault, a mechanical fault or overheating, or when the engine control module itself detects interference in the communication. It can therefore point to the alternator, its drive or the wiring.
Possible causes
- Worn brushes (carbon) in the alternator
- Damaged alternator
- Damaged alternator control module (ACM), which is also the charge regulator
- Damaged drive belt, belt tensioner or freewheel
- Contact resistance and oxidation in the terminals
- Open circuit or short circuit in the LIN wires
What you can do
- 1Check that the connectors at the alternator control module are fully seated and free from oxidation
- 2Check that the drive belt and belt tensioner are intact and that the air intake and outlet at the alternator are not blocked
- 3With a multimeter, check that the LIN wire has no open circuit and no short to ground or supply voltage
- 4If the fault returns after these checks, have a workshop inspect the alternator for worn brushes and the freewheel, since this needs measuring and dismantling
Symptoms you may notice5
- The generator not charging warning lamp lights while the engine is running
- The battery discharges
- Noise from the alternator or the drive belt
- The engine judders under acceleration
- The headlamp bulb blows
General guidance for car owners. Diagnosis on the car can point to a different cause.