1024kb RR with 512kb tune

[Mayhem]

Hi Guy's
I have decided to start a new thread instead of hijacking limitedcv8r's thread.
At first I could not load a 512kb tune to my 1024kb RR which I have now sorted out by holding the Shift & Ctrl when clicking on the download button. I now have a new problem, I have loaded the 512kb tune to the RR but now the vehicle will not start! I have tried 3 different tunes and have had no joy, yet the same tune in the std. ECU works fine. Has anyone else had this problem?

[N0DIH]

Probably need to do Security learn. From what I gather the BCM gets the PCM Serial Number and if that has changed, then it won't start unless security is relearned.

Give it a try.

Or simply turn off VATS....

[L31Sleeper]

I believe Shift+Ctrl is only useful if you have removed your RR from the 1024k PCM and installed it in a 512k PCM.
After all you can't bolt a 512 PCM in a 1024 PCM car or truck.

Hope this helps.
-Justin

[Mayhem]

I have turned the VATS off, still no joy. I have loaded a 1024kb tune onto the RR and had the truck running. I dont have a 1024kb ECU to use in the vehicle but have the 512kb ECU that I ultimately will be using. It is just such a mission not being able to use the RR for tuning.