As said before p0700 "ETAX DTC present" is a PCM code that is triggered when there is a fault detected by the TCM. p0700 only turns the mil light on, it is not for diagnostics.

You need a scan tool that can communicate with the TCM to see what the detailed faults are then diag those.

For a "delayed engagement" after a long soak (hours) I would guess Torque converter drain back and/or weak pump. (have done many)

If this happens after just a few minuets of off time I would think it is an electrical problem or a sticking valve in the valve body.

Good Luck,
Gary.