Toyota Previa Owner's Manual page 115

3. Input the existing three-digit code.
You have 10 seconds to enter each digit.
For example, "209":
To set the first digit: Push "1" until the digit
you want appears on the display.
To set the second digit: Push "2" until the
digit you want appears on the display.
To set the third digit: Push "3" until the digit
you want appears on the display.
110
4. The three-digit code should be on the
display.
Push and hold in "SCAN" until the display
goes dark. (At first, "SEC" will appear on
the display.)
If you pushed any wrong buttons,
"Err" and the number of errors you
have made will appear on the display
before "SEC" does. Go back to step 2
and try again. If the display returns to
"---" while you are entering the code,
go back to step 3.
To make sure the security code has been
accepted, turn the ignition to "LOCK" and
then back to "ACC". "SEC" should appear
on the display.
NOTICE
A tenth error will activate the
anti-theft system and "HELP" will
appear on the display. The audio
system will be completely inoper-
able. At this time, the anti-theft light
also comes on. If this occurs, con-
tact your Toyota dealer.