Quite often an error will trip once only. Especially after a major repair.

Do you recall the precise error?

Fuel trim error can be reset in a way that forces the ecm to re learn the fuel trims. In this case if there is a problem it will come back but might take a month or more.

At this point you don't have to worry but you can use a scanner that will show real-time fuel trims and see if they are normal

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