After you replace the parts the check engine is still on how long it takes to read the code?

After you replace the part the computer code must be cleared, erased. You can accomplish this in one of two ways. 1-get a scan tool, or 2-disconnect the negative (-) battery cable for at least 30 seconds. This forces the computer to start it's monitoring of the sensors all over again, believing they are all in working order. Now if the light comes back on, this means a problem still exist. This could be the part you replaced, or whatever else made the code appear and maybe it was'nt the sensor after all. There is more involved but let's go with this.