Two questions

[Pilly]

I am interested in buying a code reader for my 2001 2.5 Elite what protocol does it use.

I am also interested in updating my transmission software, how do I do this.

I have a code reader from my old car is this any good?

http://www.auteltech.com/gs400.htm

[Jimbob]

I Think that code reader will work....you wont do any harm plugging it in to try.

For the autobox software, you need someone with a tech2 (and knows how to use it)

Theboy and Marks DTM calib on this site each have one.

Vauxhall can also do them, but may charge double / treble.

Where are you based?

[Pilly]

Plymouth, must put in my sig  

[Marks DTM Calib]

The protocol is mainly ISO based KWP82 and KWP2000 on Vx cars of this era (note, the Omega with the 2.5 is NOT OBDII!)....

[TheBoy]

cheap generic readers dont work on 2.5 engine.

[motmann]

cheap generic readers will read your auto-box (launch x creader)