I just did a timing belt change on my 2015 Accord Coupe 6-6. To get at the timing belt I needed to disconnect the battery and remove the ECU from the car as it was in the way of accessing the motor mount that has to be removed to get the belt and water pump out. Anyway, when I got everything put back together I went for a drive and everything seemed fine, however I noticed it wasn't driving the same as before. The tune I load (91 octane tune) includes a reduction in rev hang to 20 perecent and I have the 2-step set to 3000 RPMs. I was noticing that the rev hang was higher than normal, When I came to a stop the 2-step was not present as it would let me rev the engine to the moon. I was able to reload my tune without issue and things returned to normal, but I just found it odd that the tune was "lost" when the ECU was disconnected. I've disconnected the battery before and it never changed the tune so perhaps it was the fact that the ECU was fully disconnected from the car?
The additional odd thing was that all my other settings for the seat, radio presets, connection to my phone via bluetooth, even the HVAC settings, etc. were all preserved.
Does this make any sense that the tune was lost by disconnecting the ECU? I thought Ktuner overwrote the tune, not sure how the computer would have defaulted to anything different (stock).
ECU forgot my tune?
Re: ECU forgot my tune?
When you flash an ECU you overwrite the data that's on it. It's not possible for an ECU to change tunes without flashing. Other saved items like fuel trims and adaptations are reset when battery is disconnected.