VOLVO
ECM-U012086 - Lost Communication with Starter/ Generator Control Module. Bus Signal / Message Failures. Signal invalid
System
Engine Control Module (ECM)
Volvo models this fault code applies to
Applies to the following models:
7 modelsS60 (2011–), S80 (2007–), V60 (2011–), V70 (2008–), XC60 (2009–), XC70 (2008–), XC90 (2003–)
Show models by year and engine (19)
- Volvo S60 (2011–)2011–2014Engine B6304T4 only
- Volvo S60 (2011–)2015Engine B6304T3, B6304T4, B6304T5 only
- Volvo S80 (2007–)2007Engine B6324S, B8444S only
- Volvo S80 (2007–)2008–2009Engine B6304T2, B6324S, B8444S only
- Volvo S80 (2007–)2010Engine B6324S2 only
- Volvo S80 (2007–)2011–2015Engine B6324S4 only
- Volvo V60 (2011–)2011–2014Engine B6304T4 only
- Volvo V60 (2011–)2015Engine B6304T3, B6304T4, B6304T5 only
- Volvo V70 (2008–)2008–2009Engine B6304T2, B6324S only
- Volvo V70 (2008–)2010Engine B6324S2 only
- Volvo XC60 (2009–)2009Engine B6304T2 only
- Volvo XC60 (2009–)2010Engine B6304T2, B6324S2 only
- Volvo XC60 (2009–)2011–2015Engine B6304T4, B6324S4 only
- Volvo XC70 (2008–)2008Engine B6324S only
- Volvo XC70 (2008–)2009Engine B6304T2, B6324S only
- Volvo XC70 (2008–)2010Engine B6324S2 only
- Volvo XC70 (2008–)2011–2015Engine B6324S4 only
- Volvo XC90 (2003–)2005–2006, 2011Engine B8444S only
- Volvo XC90 (2003–)2007–2010Engine B6324S, B8444S only
What does this fault code mean?
The engine control module (ECM) controls the alternator charging voltage via LIN communication with the alternator control module (ACM), on request from the central electronics control module (CEM). The code is set when the engine control module detects a disturbance in the communication, and it concerns an invalid signal on the LIN network. Although the code is titled lost communication, it concerns the signal from the alternator control module.
Possible causes
- 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
- 1Check that the fuses are intact and that the battery is well charged
- 2Check the connectors at the alternator and at the engine control module for loose or oxidised contacts
- 3Look for chafed wiring on the LIN signal wire. Use a multimeter to check that it has no break and is not shorted to ground or supply voltage
- 4If you have a diagnostic tool: read the alternator status in live data with the engine running, and check whether the fault returns after the connectors have been checked
- 5If the fault returns: have a workshop with diagnostic equipment check the alternator control module and any other control modules on the LIN network
Symptoms you may notice2
- The battery discharges
- The battery is dead or shows low voltage
General guidance for car owners. Diagnosis on the car can point to a different cause.