to get the pcm to relearn you have to disconnect the battery for a few hours. correct? what exactly would be the advantage of this and is it very noticable after you do. 96 ssei with 87,ooo mi.

5 minutes is probably plenty. Or just pull the PCM fuse. Go 10 or 15 to be sure. The only reason you'd do this is if you did a major mod, or were having problems.

Yes & NO! Yes it will cause the PCM to enter the "relearn" mode but, No it may not erase all of the stored codes!

Is this the same for an 88 SSE? If I had the battery off for ~5 minutes, would any codes clear?

Current codes will clear. Some history codes will remain for a certain amount of time.

If you want to reset your computer, disconnect the negative battery terminal and hit the brake so the 3rd brake light can use up the remaning electrons in the system. And no the computer will not forget the codes because they are stored in flash, and are not lost due to lack of power but when they are overwritten. Sorry bud. But that'* the procedure for resetting your PCM. Takes about 5 min max.

OBD1 will erase completely, all codes.

But BUBBA has a 96 SSEi. OBD IIish.

Oh, let me be right about SOMETHING!

An OBD I system can erase codes stored in it by disconnecting the battery, except for 94/95'* with the OBD II terminals, which have to manually erased by a Tech II Scanner. The earlier (Pre-92'*) CCC systems can be erased by just disconnecting the battery too. The trouble all starts with the OBD II systems, these have to be manually erased by a Tech II Scanner.