Will start then dies after a fewsecounds. Securityight stays on. Haave tried to reset doing the key on for 10 min then off but when i turn key on i can wait 30 mins and security ligjt nevergoes off. I don't have a key fob. My ignition key iss different than doir key. Use to i could unlock door nd pur key in ignition to turn security off now it won't trn off the flashers go off even when key is in ignition. All of this happened after welding a bracket for muffler on car. Did not disconnect battery before had. Evape system o nly code ir dhows.. any advice would be great

 

Uh. Really hard to read your post. Maybe you could repost it with some corrections ? You should also post the CEL code number. Not just a generic description.

Your bio shows your car listed as a 2006 “SS”. Since there is no such thing, you really should clear up some of what you’re asking for/about.

 

Does the ignition key have a round hole or, oblong hole? Round is the recall oblong is bad.
Have you checked the battery and the continuity of the wire between the starter and alternator. The security light usually comes from a dead battery.
Check the maxi fuse near the battery.
What is the "evap" code?
Arc welding can cause a major short circuit.

 

The welding might have damaged an already old low voltage battery, less then 12.4 volts static is a dead battery

 

Welding could have blown something or even a module. You need to put a good scan tool on that thing and see what's going on.

 

It has the round hole key. Looked inline and it has had all gm recalls done. Scan tool says evap system. And main fuel pump relay. Don't remember the exact code numbers but I'll post them when I get home. And give more details.

 

My guess is a clogged cat.

 

I’m still thinking a fried cell in the battery

 

I apologize for my delayed response. Broke my phone. These are the only codes it shows. Po341 . Po366 . Po446 and Po230. I've changed batteries and even had battery charger hooked up on 200amp jump start. Still started and died. I've jumped the fuel pump relay and still dies. I did find that the passkey 3 fuse location 9 i believe >interior fuse box was missing. No idea how that happened. With fuse in now the security lught flashes fast and it won't start everytime now like without the fuse .it still dies after 3 sec. Thx for anu hel]p

 

The P0230 is telling you that the fuel pump relay is turned off. The computer thinks the car has been stolen and is shutting it down.
The other codes are probably fuses under hood.
Are you using a key with the + inside a circle?
Fuse #9 is the brake lights, #8 and #10 are PK3.

Why do you have 2 different keys?
Is the ignition key the one that came from the factory, is it matched to your VIN?
A locksmith could fix that.
You might need a locksmith to reprogram your key to the car.