89 Toyota Pickup jumping diagnostic port doesn't change timing


I asked this a little while ago and didn’t get an answer, but that was right when they were changing the board over and things were a little hectic, so I figured I’d try it again.

I noticed when I was setting the timing on my 1989 Toyota Pickup (2.4L 22R-E) that when I jumped the two terminals that you’re supposed to, the timing doesn’t change like its supposed to. The check engine light flashes, so its getting into diagnostic mode.

I have the timing set where it runs well and doesn’t knock, but I’m still curious as to why it doesn’t work like its supposed to. Any ideas?