You can try disconnecting the battery for 5 minutes, that's how it's reset on a 1991.
Buick didn't make a Rainier in 1994
vehicle will not start how do I reset the computer you don't need to
The 1994 Buick engine control computer is located behind the passenger side dashboard. You will need to remove the glovebox in order to access the computer.
On my 1994 Lesabre it is under the dash about center at edge of carpeting
Unhook the negative cable and wait ten minutes, the computer is reset.
You would need to disconnect the battery for at least 5 minutes. This should reset the computer system back to manufacturer settings.
with hand held computer (scanner)
I think you just disconnect the battery then reconnect
Disconnect the battery for a few seconds, then reconnect.
the older cars u can unhook the battery for 15 minutes but with the new computers in the cars today u have to unhook them for 30 to 45 minutes then it will reset the computer
1995 Buick LeSabre how do i reset my radio
Unhook both sides of battery and wait 1 minute, this will reset reset the computer to default.