i have a no start condition
my 2012 VW GTI starts and stalls also the dash lights are cycling on and off.
When disconnecting the battery it will sometime reset and start
Don't disconnect the battery , you need to read the codes , the problem(s) may be beyond your scope .
Sounds like the security system is in active mode, it will let it start then cancels the fuel pump circuit so it dies. As this is a VW the dealer is the only place to get the security system reflashed. Disconnecting the battery can and will cause more electronic problems so don’t do it unless you have the right equipment to keep the computers energized during main power disconnects.