In any Gen 5 AT, when the shifter is in second gear, the trans will not start off in first (like when the shifter is in third gear), but starts off in second and stays in second. I am guessing this is a function of the TCU. Is it possible to reprogram the TCU so that it will start if first, then shift to second when the shifter is in second? This is a pet peeve of mine and one which I would like to fix.

 

AFAIK it's a simple override/bypass when selecting 1st or 2nd, no shifting logic is used nor are any sensors used as inputs as the transmission is simply placed into a gear with no need to shift.
I highly doubt you would be able to program the TCU for a 1-2 only shift using D2.
Even if you were able to you would still need to modify the valve body in the trans for the 1-2 only shift.

Any reason other than not wanting to shift manually from D3>D2 or D1>D2 to get your 1>2 only shfit event?

 

Nope. I shift manually a lot and sometimes forget and leave it in 2nd at a stop light. Then it tires to start of in second, which is not good. I just wish it acted like it does when it is in 3rd. Probably should convert it to manual, but I spend too much time sitting in heavy traffic to make that any fun.

 

Me, and please don't take this the wrong way. Either swap in a manual or leave it in D4 and enjoy.