I just wanted to post my experience with this problem. Wife went to work in car. Came out to come home, car wouldn't make a sound. Dash lights worked but when tried to start everything went out. Message center on dash flashed through several messages, Service soon, Service Trac, Door ajar, red battery light and security. Replaced ignition lock cylinder ($168 at Auto Zone). After the relearn procedure Security light would go off at times, other times it would come back on. Called dealer, they told me I had same problem just after hurricane Katrina. I knew it went in but didn't remember why due to everything else going on with living conditions.

This time I was told bring it in they would allot 1 hour ($95) for diagnostic. The next day they said couldn't find a problem need to allot 4 more hours and I needed a new battery (The one in the car was tested at Advanced Auto Parts the day before and tested good. The following day they said they found the ECU was bad and needed replaced, and there were other issues I might need to address. I was a mechanic while I was in the US Army, fairly good mechanic but have to stop at electronics, especially when something need programming that can only be done by a blackmailing, opps I mean a Chevy Dealer. The total came to $1908.57. The ECU on the bill is marked "Remanufactured" And they changed the oil, preformed a lube job, serviced my fuel injectors, serviced my trans mission and changed the wiper blades. As I was paying I had to sign for a recall they preformed. Something to do with plastic cover on the key. Knowing the transistor is in that part of the key and fact they couldn't explain what the recall was, labeled general maintenance ring and cover on my bill. I now wonder it that wasn't the whole problem and the rest just padding.

They offered to sign me up on the preferred customer plan. I have been a Chevy man since the early 70's. I declined and informed them next time this one breaks down it wont be repaired and there will not be another GM Product in my drive way.

I have a Chevy 2004 Impala LS- This car has multiple problems over all (control panel not working-" traction off" comes on and car doesn't want to start). However, right now I keep getting stranded when I take the car out. The Security light keeps flashing and the car won't start. I have to set the ignition to on and monitor the security light flashing at me for about 15 mins until the security light stops flashing then the car will start. Today I had to go through the process 3 times before car would start. It was 97 degrees out today. I am stranded in parking lots and always have to be aware of what is going around me. With the recession there are always panhandlers coming up to me begging for money and this frightens me. I have fought with Chevy about this problem and they refuse to address it unless I take it to a Chevy dealer only and pay for diagnostics and repairs. With all of the complaints about this problem I believe it is Chevy's responsibility to fix it. I have already informed my family that if anything happens to me they are to go for Chevy as my safety was ignored by them.

PLEASE try this before you do anything else. DON'T pay GM or your dealer for a new ignition, BCM, or anything else that probably won't work anyway. I tried everything as I've had this problem(I'll skip all the details since we've all dealt with the same aggravation) off and on for quite a while. I followed the advice of someone else on this site and it absolutely worked for me. Locate the BCM (computer) under the dash on the driver's side by removing the panel by lifting the two tabs. Unplug the grey connector that is the electrical connection between the ignition and the BCM. It is the farthest one in and is one of three connectors in the black box (BCM). Spray both ends of the unplugged connector with electronic connector cleaner. I got mine at Advanced Auto Parts for $7.95. I plugged the connector back together, turned the key, and voila! She cranked right up. It's been two weeks so far and no problems. I'm also going to try a premium spray you can get online for about $20. It's called deoxIT and someone else on tis site has used it and has not had a reoccurrence of the problem for 2 and a half years. these products remove the oxidation from the crappy materials that GM used to make the connector pins. Good Luck!

2004 Chevy impala wont turn on i hear it could be the ignition switch but I am not sure,every time i go to start the car nothing happens no noise nothing,but i do get a Security Warning in the message box.i have 88,000 miles on it and the car runs great when it runs.i checked all fuses in and outside of the car and all are accounted for and working fine.I also tried and disabled the alarm in the radio console but still it wont start.its saturday now and i need to know or at least have an idea whats the problem so when i take it to the mechanics on monday they don't take me for my money,all help will be greatly appreciated

The Security light comes on and then it is a game of Russian Roulette from that point. At some point the car will not start. I can get it started after leaving the key in the ingnition in the ON position for about 10 minutes or so, it has been a liltter longer lately. I have taken the car in to have it looked at, but the mechanics can only read the problem when the Security light is on. I got lucky once, and the Security light come on when I was able to get to the Chevy dealership from which I purchased the vehicle, and they were able to get a reading on the problem, or so I thought. I had the BCM replaced for $479, only to have the problem reoccur one week later. I took it back but the sympton did not repeat itself, this was in April of 2011. Frustrated, I just learned to live with the problem. I have asked several mechanics what the possible causes are, and all have said I have to take it to the dealer when it comes to the Security light. Well, I did and it cost me $479, with a "well it could be the PCM, but we are not sure" Oh by the way, the not sure factor could cost me $500-$700.

I will be in the market for another car in the next few months, and I will tell you, I will not be looking at a Chevy product.

the problem with security light coming on,then after the engine will not start. is this suppose to be a common problem? what is general motors saying about this problem with these cars? is there a recall concerning this problem? kinda reminds me of the chrysler era when they were putting out lemon cars and just ignored there customers totally. i never bought another chrysler/dodge product again,and thinking of doing the same with gm. but, in the mean time how is this problem solved? call me sick of this problem!