I have a 2003 GTS AT. After purchase tranny went bad. We bought a GT Tranny from 2000 model. Tranny works fine, and drives fine. But later on while driving it, it threw a SES code saying the gear ratios are incorrect. This is because the GTS have a slightly dirrenent final ratio and as well as 1st and 2nd (because the GTS having more horses from the varaible intake, therefore there a two types of trannies for the 3.0 ats). The ECU is picking this up and throwing the tranny in limp mode.

I've heard the ecu can be reprogrammed with the 2000 gear specs and everything should work fine. Does anyone know who does any ECU tuning or reprogramming for our cars. I cannot afford to buy another transmission, and it would be even harder to find a gts tranny at that.

Anyone know of any other options. All help would be greatly appreciated.

as far as i know, the dealer is the only one that can reflash the ECU....or you can buy the tool for like $13k. :lol:

you could also look into getting a GTS ECU

the original tranny wasn't covered under warranty?

The car was bought at an auction with slight damage, i guess the original tranny might have been damaged. So we found a GT tranny and put that in. The GT tranny is not working with my GTS ECU.

You think a GT ECU would work in my GTS? Its worth a try if I can find a cheap one.

But I am sure if I can just change a few gear ratios in the current ECU everything will work fine, then the car will not thorw that SES code and put it in limp mode.

i don't know what i was thinking....that was too early this morning. I don't think a GT ECU would work b/c then you might lose the functionality of the intake runners on the GTS. I would take to a dealership and see what they say about it. maybe Mittech can chime in.