Aznstylistic

Hey I'm from Memphis,TN and we currently have no tuners in town for my Evo X. I heard of a one or two guys in town that tunes evo 9's and 8's. I had a ASE certified technician who has the newest Snap On Scan tool. I know it does not matter if he does have that, and i know he not a certified Mitsubishi Technician. But i know this guy is very good in diagnostic in all sorts of cars. Well my ABS and TCS light is on and we check the scan tool and i had a code for low voltage to ABS, I forgot the code for it, but you guys probably know since there is an issue on google and the forum about evo having this code. Well i call a few tuners near TN which was either Atlanta or Texas that does dyno tuning for Cobb AP. They both said that i need my codes to clear before they can tune my car. So my Technician check the abs voltage and it was fine and reading battery power, but he said my battery had a slow start too it. My car usually sits in garage and i drive it once in a while, i only have 60k miles on it and it's has the original battery from the dealership which they gave me an Optima. Today i bought a new battery that matches it bc im not paying dealership price for a battery. It has a advance auto battery that matches, because i went to NAPA where i usually go, and even tried auto zone they didnt know ****.
My question is this, is it true that tuners need the car to have no existing codes to tune your car? My AFR is all over the place, I don't see a good solid 12 at WOT or just normal driving. I'm running pretty much lean, so i really want to get a tune before i sell this car to my friend. I dont care about crazy power, i just want a reliable tune. I dont mind buying few more parts to make it run good. If ya'll got any good advice what i should do and where should i go to get tune near my area. I'm open up to switching to open source tune and getting an e-tune if i have to.



2010 GSR
Mods:
AMS Short Intake
AMS full turbo back exhaust with a Berk test pipe.
AMS FMIC
Injen UICP
AEM AFRC
Cobb AP V2 on STage 2 Mapp from 3 years ago.