theft light on when driving

i have an 03 malibu since january, and since january i used a hardware store key to start it and open doors. however, recently the passlock system rejected it, and i had it towed, got hte original key, got it reflashed, and now i use that. however, the light comes on when im driving half the time. is this a serious concern? i read the manual and it said i should take it to the dealer since its the passlock system having some sort of issue. however, i dont want to take it to the dealer unless i really have to. i dont live in a part of town where cars are stolen regularly, and i dont keep valuables in it.

any input or comments would be lovely. if this topic is already in another threat i apologise, im a bit of a noob to this forum :)

Theft light on while driving means that your ignition lock cylinder is about to go. And it's time to trade that piece of.....

so its not a theft system issue at all? i dont have the money to trade in my car and get a new one right now. i dont think id get a lot trade in even though i only have 39409 miles on it. is the ignition lock cylinder something that would cost a huge bundle? and what happens when it breaks? i assume it means i can't start my car....:confused:

also, does it matter that the theft light stays off when the car is off? when i start the car, sometimes the light stays on when im driving, other times it turns off only for me to glance down at my dash some time later to see that its back on. other times it remains off.

here's a popular thread to explain it.

http://www.automotiveforums.com/vbulletin/showthread.php?t=454520

i have a 99 malibu, and this was one of the issues we had--and managed to fix. it might be the entire igntion switch--or you might just have to clean the actual lock mechanism. the switch is around a hundred, to clean it is just a few dollars on a can of contact cleaner!!!
when the light is on steady, it means the device is having a problem, it flashes when its performing the anti theft procedure.

Sorry, I was away for a few days. On my '98 Malibu, the theft light came on while driving numerous times. I had the ignition lock cylinder replaced 7, yes 7, times, all under warranty, fortunately. The last time it acted up, it shut down the ignition (I think there was a mandatory wait time of about 20 minutes before you could attempt a restart) in a line at the gas station (just after refueling).

Needless to say, I ditched that P.O.S. (I do happen to think all '97-'03 Malibus and '04 Classics are POS's) soon after that incident. Not to say the '04 Maxx ($4,000 Owner Loyalty rebate, which trick GM is trying right now again, as if they know that I just paid off the '04 - since it's GMAC, I guess they do) hasn't been without problems. It's been another pain in the you-know-what, but a tad less severe than the '98.

I'm not falling for yet another Malibu. The '08s are off to a pretty good start, but time will tell. No more Chevys for me for a while. Sorry, GM!!

When the theft light comes on while driving you're home free. That means the system experienced a fault after starting and it recognizes it as a false positive. So long as it stays on the car will start; the light on is just an annoyance. You may have a problem if the battery discharges or is disconnected, then you'll need your ignition switch to send a good reading to the theft system. Follow the link above to the explanation and fix. I installed a resistor in my circuit and have been good ever since.