VOLVO
ECM-U012D87 - Lost Communication With Generator Control Module. Bus Signal / Message Failures. Missing message
System
Engine Control Module (ECM)
Volvo models this fault code applies to
Applies to the following models:
8 modelsS60 (2011–), S80 (2007–), V40 (2013–), V40 Cross Country (2013–), V60 (2011–), V70 (2008–), XC60 (2009–), XC70 (2008–)
Show models by year and engine (8)
- Volvo S60 (2011–)2014–2015Engine B4204T10, B4204T11, B4204T12, B4204T15, B4204T9, D4204T5 only
- Volvo S80 (2007–)2014–2015Engine B4204T11, B4204T12, B4204T15, D4204T5 only
- Volvo V40 (2013–)2015Engine B4204T11, D4204T14 only
- Volvo V40 Cross Country (2013–)2015Engine B4204T11, D4204T14 only
- Volvo V60 (2011–)2014–2015Engine B4204T11, B4204T12, B4204T15, B4204T9, D4204T5 only
- Volvo V70 (2008–)2014–2015Engine B4204T11, D4204T5 only
- Volvo XC60 (2009–)2014–2015Engine B4204T10, B4204T11, B4204T12, B4204T15, B4204T9, D4204T5 only
- Volvo XC70 (2008–)2014–2015Engine B4204T11, D4204T5 only
What does this fault code mean?
The engine control module (ECM) sets the alternator charging voltage over LIN, following requests from the central electronics control module (CEM) on CAN. The code is set when the engine control module detects that messages from the alternator control module (ACM) are missing, meaning an expected message does not arrive.
Possible causes
- Contact resistance and oxidation in the connections
- Short circuit between the LIN wires
- Open circuit in one of the LIN wires
- Internal fault in another control module on the same part of the LIN network
- Faulty alternator control module (ACM), including its charge regulator
What you can do
- 1Read the codes in the engine control module and fix other LIN-related codes first
- 2Check that the fuses are intact and that the battery has good voltage
- 3Look for chafed or pinched LIN wires. Use a multimeter to check that they have no break or short to ground or supply voltage
- 4Check the connectors at the alternator and the engine control module for oxidation and loose contacts
- 5If you have a diagnostic tool: check the fault's status indicators and freeze-frame values to see when the fault occurred
- 6If the fault returns: have a workshop with diagnostic equipment check the alternator control module and the LIN network
Symptoms you may notice4
- The battery is dead or shows low voltage
- The engine is hard to start and the starter turns over slowly
- The engine lacks power, especially when the car is moving off
- The engine hesitates, surges or runs unevenly
What the fault can affect1
- The alternator control module charges at a fixed voltage
General guidance for car owners. Diagnosis on the car can point to a different cause.