Originally Posted by Mike Benvo
If the SES light is on after programming the tune, you should start the car four times. After the forth start the CEL will clear. Even though the CEL is on, there will be no faults stored.
Reason for this is that on some cars the ECU needs to be cycled 4 times to clear the bootloader from thinking there is an error with the checksum correction. It will turn off on the fourth start like clockwork.
It is gone now. Now I know though.