I have an 82 Sabre and solved this by removing the battery probe and inline resistor, it unplugs from the sending wire at a connector a couple of inches from the probe. Connect the sending wire to any positive wire, insulate the connection to avoid shorting the electrical system. I kept the old connector intact and saved probe in case some time I will want to reinstall the battery probe.
run the wire that goes in the battery directly to the positive side of the batt.problem solved
You can not bypass the passtime. WARNING: if you have passtime and bypass it and the dealer finds out you did they can and most likely repo the car and not refund your money. you signed a contract for passtime when you bought the car.
Take out the battery.
Starge wired to battery
The oil pressure sending unit is mounted under the distributor, some can be accessed without removing distributor. It can be removed and plugged with a 1/8" pipe plug to bypass.
Unplug the battery, and wait 10 minutes to plug it back up.
If I was you I would disconnect the battery.
take out cmos battery for 2 min
I recently bought a pioneer avic f900bt bypass guide from http://www.underground-secret.com/pioneer_avic_f900bt_bypass.html If you want I can send it to your email ;) It shows you everything you need to do and comes with color pictures, very easy to bypass the avic f900bt.
You can disconnect the battery for ten minutes and it will reset
try pulling the fuse out
on a 1989 Cadillac Seville you can bypass the ignition by running a wire to the starter and one from the battery until you can get it fix