I have a brake light bulb fault error and I replaced both of them and now they both work (I've tested them to make sure) but the error code won't go away. How do I make the error code to go away so when I turn my car on it won't show the error code?

I have a 95 f150 xlt 351w. Had the motor changed (same motor less miles). Im getting a check engine light only once i start driving. Goes away after truck is shut off. No blinking no other lights. Seems to only effect the shifting of the tranny. Any other fixes then a ecu reflash? And if so...