So I bought a new car a couple months back and my 2007 S40 T5 sat for about 2 months without being driven. When I went to start it the battery was dead, charged it and started right away. When I drove it I got the "Reduced Engine Performance" light. I removed the negative terminal overnight thinking maybe light would clear up but no luck. The battery seems week but has started the car several times now. The battery is a 6yr Interstate that is about 5yrs old.
Could a weak battery cause some voltage issue and the REP? I have blue driver scanner but it doesn't pickup any faults/codes.
Thanks for your help!