So, 858.7625 is the active control channel, and probably won't change ever, so you can delete those other 6 channels. You say that you hear the "idling diesel" sound, so you're within receiving range of the site. Though, as noted, the decoding percentages are rather low - work on the antenna or move the radio around to find a spot in the room that provides better reception. You say the channel shows +MO in the top right corner, so the channel is set to the correct mode and the bank is open. All good.
When manually stopped on the control channel, you could press ./DELAY because you don't need delay on it. Then press PROG, followed by TRUNK. Make sure that it says "MOT: " on the third line down. If not, press MODE until it does. Then press scan.
Then make 100% sure that the bank that the control channel is programmed in is the only bank that's active when you scan. In other words, if 858.7625 is programmed in, say for example, channel 230, make 100% sure that bank 2 is the only bank being scanned when you press scan.
If you do all of this and work to improve your reception, then you should hear SCHP. If it still doesn't work, maybe by some weird chance you've locked out the active talkgroups.
To chech this, press PROG then TRUNK, then FUNC, then L/OUT. If it displays a talkgroup with an "L" next to it, press L/OUT to clear the "L". Do this repeatedly until no more locked out talkgroups appear. Then press scan again.
Let us know how this works.
So, w