Geo 1995 Prizm Owner's Manual page 117

How to Shut Off the Theft-Deterrent Feature
If your radio is secured (SEC shows on the display) and
you wish to disable it, enter your security code as
follows, pausing no more than 15 seconds between
steps.
Press the 1 and 4 buttons together. Hold them down until
SEC shows
on
the display. You are now ready to enter
your security code.
Press the SEEK 4 button and hold it until the first digit
of your code appears.
Press the SEEK b button and hold
it
until the second
digit of your code appears.
Press the TUNE 4 button and hold it until the third digit
of your code appears.
Press the TUNE b button and hold it until the f
rtn
digit of your code appears.
Press AM-FM after you have checked that the code you
entered matches the one you wrote down. "0000" should
now appear on the display and you will need to repeat
the above procedure.
If the code is correct, the radio will now operate. If the
code is wrong, Err will appear in the display.
To Unlock the System After a Power Loss
If power is disrupted to the radio while in the SEC
mode, the unit will not work and LOC will show on the
display whenever the ignition is on. To unlock the unit,
press 4 SEEK b or 4 TUNE b and "0000" will appear
on the display.
Press the SEEK 4 button and hold it until the first digit
of your code appears.
Press the SEEK b button and hold it until the second
digit of your code appears.
Press the TUNE 4 button and hold it until the third digit
of your code appears.
Press the TUNE b button and hold it until the fourth
digit of your code appears.
Press AM-FM after you have checked that the code
matches the one you wrote down. Now the time
of
day will appear on the display. (Please note that if an
incorrect code is entered, Err will appear on the display
and the above steps need to be repeated.)
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