Could be a few things.

.When my 4.4 hit 100k miles I was getting it often, changed the 'lifetime' fluid-pan drop, and it went away. Did another pan drop and changed the valve body seals this time which were cracked, and the entire demeanor changed for the better. Have done 3-4 more pan drops fluid changes since. 194k mies or so and still on the original trans. Also no more codes.

.Could also be debris as stated above.

.Low trans fluid

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E53 X5 4.8is-Dinan S2-Street Brawler
E70 X5M-The stoplight shocker
AMG E55K-539 RWHP, 629RWTQ-my toy
GX470-the unbreakable truck.
F30 328i-JB4 STG 2. Daily MPG Work Beater
02-WS6, 6sp my other toy
...other stuff parked around here somewhere