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Nope. No flash codes on OBD2 (post 1996) vehicles, not even 1996+ Jeeps.
You must have a scanner as SLCHOE states. There are relatively inexpensive scanners available (Hfreight) but you say you have one. 20 years ago some cars had series of flashing lights that meant particular but unspecified things, but actual drivetrain codes are specific and must have a scanner.
On my 98 Cherokee and 2007 Wrangler,
I get the codes by turning the ignition key 3 times on and off.