The pins on my LS1 scan tool are wired differently to the diagnostic connector on my LS2 ecu connector. How come if this is all OBD2 ? Can someone please explain this? Thanks.

 

It uses a different wires in the obd2 connector because the protocol changed from serial single wire data bus to CAN bus about 2005. Can bus for GM buss pin 6 and 14 for data.

 

Thanks for that, don't understand a word of it but glad you have explained why.
Just another thought, on ebay there are hundreds of OBD2 scan tools which do not differentiate between which year they serve, how can this be?

 

Scanners read the data from all the available pins, finds and active one and then sends commands to see what language it is speaking. Once the scanner determines the language, it then reads the data and trouble codes appropriately. OBd is a standardized language but has been revised over the years plus there are some commands that are OEM MFG specific. So they work with GM but ford is different from imports, etc.