2000 Oldsmobile Alero security light on.
I just tried to start it. I just changed the ignition cylinder tumbler because i could not turn the key to start my Olds Alero. The security light is flashing the dash. Why is the light on. I have read in other forums that i need to re-learn the theft code. How do i do that fix. Is it easy or do i need to go to the dealer. How much would it cost for this repair.J

K:This is a common problem on this and many other GM vehicles. Perform this relearn procedure below. It will get the car to start.

Attempt to start the engine, then release the key to ON, vehicle will not start.
Observe the SECURITY telltale, after approximately 10 minutes the telltale will turn OFF.
Turn OFF the ignition, and wait 5 seconds.
The vehicle is now ready to relearn the Passlock Sensor Data Code and/or passwords on the next ignition switch transition from OFF to CRANK.
Start the engine, the vehicle has now learned the Passlock Sensor Data Code and/or password.

Best to have a battery charger on during this time to avoid a weak battery.A very weak battery can cause programming failure.
1996 Oldsmobile Achieva. Check engine and security light.I have put in 2 sets of gauges and a new AC Delco lock cylinder. My keys have no chip in them. The gauges worked after repairs then when I went to pick it up from the mechanic no gauges worked. I drove the car home. I just started the car and the check engine and security lights stayed on and the gauges seem to be working again.

The gauges were replaced twice, the first set the speedometer did not work in the set so I got another set, and my mechanic put in a new AC Delco lock cylinder. When I picked up the car the gauges did not work and I drove home. I just started the car and the gauges seem to be working in park (I did not try to drive to see if the speedo works, but the tach does now, seems like the gas and coolant too) and the check engine and security light stay on. How can I clear the computer and turn off the check engine and security lights? My car does not use a chip in the key.

You would need a proper scanner to clear any codes and turn off the check
engine light and security light. You probably still have a problem or two since the lights are on, they are usually on for a reason. The instrument cluster could be causing problems, since it seems to work intermittently. Your vehicle should have the ignition keys that have a chip in them. That's how it would have come from the factory. I'd get the car looked at again and make sure the right parts on the car. If someone has modified the security system, it would need to be put back to factory spec. If there's an alarm or remote starter on the vehicle, that can cause security issues as well.
Oldsmobile Alero Theft Re-learn Procedure

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