RomRaider

If I decide to trade in my car and I reflash back to my original map, could a subaru dealer tell that the ecu has been flashed?

Thanks

Generally no, although there's some rumor that there is a counter with some ECUs that tells the dealer how many times the ECU has been flashed. However, it is unlikey, if that is true, that it would make any difference when trading in a car. That is, the dealer is unlikely to check/care if the vehicle is stock (or put back to stock).

what about warranty work?

There's no definitive answer here since we don't have access to the dealer's tools and no dealer tech has chimed in about it. Whether or not the ECU has some hardware based flash counter is not known for sure, but it is certainly possible. If so, then they could look at your service history and compare it to the flash counter and look for a discrepancy. That said, I've never heard of anyone being denied warranty work that was stage 1 and flashed back to stock before going in for warranty work.

Thanks