Last night I drove my moms car to work, it started fine and everything. My dad wanted to come by and pick my moms car off and drop off my truck. He had an extra set of keys for the alero so he tried to start it. It wouldnt start, we thought the fuel pump was defected because we just had it replaced. It wasnt the fuel pump it was just the security system.





Does the security system go off like this if you use a different set of keys?

IF DADS KEY DIDNT HAVE THE CHIP ( HOPE THIS IS THE CORRECT TERM ) THEN YES IT WILL FAIL TO START. NOT EVERYONE ACCEPTS THE FACT THAT THE KEY HAS TO HAVE THE CHIP TO PROPERLY MATCH WITH THE AUTOS SECURITY SYSTEM. I HAVE A FRIEND WHO TRIED TO GET A KEY MADE FOR HIS CADILLAC THINKING IT DIDNT HAVE TO HAVE THE CHIP. I COST HIM A TOW JOB TO GM DEALERSHIP AND $ 150 REPAIR BILL. AFTER INSERTING THE KEY THE CADILLAC SIMPLY DIED AND WOULD NOT ACCEPT ANY KEY. YOU MAY HAVE GOTTON LUCKY IF IT STARTED WITH MOMS KEYS.

I assume you have an Alero since you posted in that section. The PassKey I and II systems used chips in the keys. The Passlock security system in the Alero does not have a "chip" in the key, although it functions about the same as Passkey. However, it is very sensitive to which key is used, and will learn the "signature" of a key. If another key is used that is very different, it will prevent starting. As the keys and tumblers in the ignition cylinder wear, you will have problems more and more often with Passlock preventing a start. This can be delayed by using the least worn key you have. If you have one that has been rarely used, make a copy of it, and use the copy until it gets worn. Then make another copy, and use that. That will buy you some time. Eventually (around 85K miles for most people) it will just fail completely, and no key will start it. Then, a new ignition switch and cylinder will be about $400 or so at the dealer. There is a cheaper solution, however. Search for "Passlock problems" in this forum.