VOLVO
ECM-U011086 - Lost Communication With Drive Motor 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:
5 modelsS80 (2007–), V70 (2008–), XC60 (2009–), XC70 (2008–), XC90 (2003–)
Show models by year and engine (8)
- Volvo S80 (2007–)2007–2009Engine D5244T4, D5244T5 only
- Volvo S80 (2007–)2010–2011Engine D4164T only
- Volvo V70 (2008–)2008–2009Engine D5244T4, D5244T5 only
- Volvo V70 (2008–)2010–2011Engine D4164T only
- Volvo XC60 (2009–)2009All engines except: B6304T2
- Volvo XC70 (2008–)2008All engines except: B6324S
- Volvo XC70 (2008–)2009Engine D5244T4, D5244T5 only
- Volvo XC90 (2003–)2013–2014Engine D5244T18, D5244T5 only
What does this fault code mean?
The engine control module (ECM) monitors LIN communication with the alternator control module (ACM), which regulates charging. Although the code is titled lost communication with the drive motor control module, it applies to communication between the engine control module and the alternator control module. The code is set when the engine control module detects a fault in that communication.
Possible causes
- Contact resistance or oxidation in the connectors at the engine control module or the alternator control module
- Open circuit in the signal wire between the engine control module and the alternator control module
- Faulty alternator control module (ACM)
What you can do
- 1Read the codes and fix any other communication faults first, as they may share the cause
- 2Check that the fuses are intact and that the battery is well charged and has good voltage
- 3Check the connectors at the alternator and at the engine control module for loose, corroded or oxidised contacts
- 4Look for chafed or pinched signal wiring. Use a multimeter to check for a break or a short to ground
- 5Check that the engine earth points to the body are clean and tight
- 6If the fault returns: have a workshop with diagnostic equipment check the alternator control module and the alternator
Symptoms you may notice1
- Charging warning light comes on or behaves abnormally
General guidance for car owners. Diagnosis on the car can point to a different cause.