Wiring harness problem feels like. Anything that shorts the can bus can cause these symptoms. After clearing codes went away and you can drive no errors? I had my transmission connector fill with water and it acted nuts but just transmission. Feels like water in dme connector. I know you probably get no rain but car wash? Anyhow start with remove clean replace DME connectors

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2011 E70 • N55 (me)
2012 E70 • N63 (wife)