Once you fix the supposed problem, does the ECU take awhile to cycle itself and clear the codes, or do you need to go have them cleared?

I replaced the two leaky intake valve seals on the manifold near the passenger side today.

 

After a few period of successful cycles if the PCM detects no fault they should be gone away .This is how GM,MB PCMs work and I think so is X Type's

 

it will eventually erase the code..i think it does take several drive cylces to actually turn off the light(may take a while) has to be full warm up from cold .