Yes, the ECU takes some time to relearn. This applies to other repairs as well.

Don't get discouraged if the codes pop up again. The computer sometimes doesn't forget and old codes can keep popping up.

The computer in my 90 still remembers the code for a bad intake manifold gasket that was repaired about 3 years ago. I was constantly pulling the battery cables off, but eventually the light would come back on. However in a recent post there was a suggestion to pull the #6 fuse (I believe it is #6 but please do a search to verify) and that will fix it. Don't know if this works since my car was recently sold, but it is certainly worth a try.....:)

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Bessie - 95 855 GLT Sportwagon; 93 854 GLT; Inga - 90 244 DL 300k, gone but not forgotton