I think there is a different pattern for historic codes rather than active codes. If you have the historic code pattern, then your 50 start cycles (of 30 sec or longer each) will get the job done. If you have a current trouble code, you will have to fix the problem first.
TQ
Start and run for 30 secs each time will do it after 50 of them.
So start and run for 30 secs. for 50 times!? Just asking..