Join Date: Jun 2011
Location: East Central Iowa
The fuel trim values are the fine adjustments the ECM does to the VE table to more closely zero in on the desired fuel mixture. The VE values that are developed by the autotune are the "course" adjustments, the trims are a "fine" adjustments that are dynamic, ie they change all the time.
So, when you flash a new tune you should clear out the trim values.
You can reload the autotune that you just did, and then clear the trims. You can reset them anytime on the trip screen, which I do sometimes when I switch back and forth from ethanol to non-ethanol.
2015 RGU CVO........under continuous change......