Home › Volvo › 2004 › XC90 Base, AWD › Repair and Diagnosis › Engine Performance › System › Engine Control Module (ECM) Diagnostic Trouble Codes - 13 Of 13 › ECM-U012086: Lost Communication With Starter/ Generator Control Module. Bus Signal / Message Failures. Signal Invalid (B6324S5; 2011-2014) › Fault-Tracing Information