VOLVO
ECM-U012087 - Lost Communication with Starter/ 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:
7 modelsS60 (2011–), S80 (2007–), V60 (2011–), V70 (2008–), XC60 (2009–), XC70 (2008–), XC90 (2003–)
Show models by year and engine (13)
- 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 V60 (2011–)2011–2014Engine B6304T4 only
- Volvo V60 (2011–)2015Engine B6304T3, B6304T4, B6304T5 only
- Volvo V70 (2008–)2008–2009Engine B6304T2, B6324S only
- Volvo XC60 (2009–)2009–2010Engine B6304T2 only
- Volvo XC60 (2009–)2011–2015Engine B6304T4 only
- Volvo XC70 (2008–)2008Engine B6324S only
- Volvo XC70 (2008–)2009Engine B6304T2, B6324S 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 that communication with the alternator control module has stopped, meaning an expected message is missing. Although the code is titled lost communication with the starter/generator control module, it concerns the message from the alternator control module.
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
- Alternator with a charge regulator that is not intended for LIN communication is fitted
What you can do
- 1Check that the fuses are intact and that the battery has good charge and voltage
- 2Check the connectors at the alternator and at the engine control module for contact resistance and oxidation
- 3Look for chafed or pinched LIN wires. Use a multimeter to check that the wires have no break and are not shorted to ground or supply voltage
- 4If the alternator has recently been replaced: check that it is intended for LIN communication
- 5If the fault returns: have a workshop with diagnostic equipment check the alternator control module and the communication on the LIN network
Symptoms you may notice4
- The battery discharges
- Starter motor turns over slowly
- The engine jerks when the throttle is applied
- Charging warning light comes on or behaves abnormally
General guidance for car owners. Diagnosis on the car can point to a different cause.