2003 Cadillac cts battery up/won't start

Question edited for clarity.
Question moved to model category.

By disconnecting the battery, you also disconnected all the set up of the security and engine immobilizer coding.

https://www.google.com/search?q=2003+cadillac+cts+security+system+reset

How do i perform the 2003 Cadillac CTS anti theft reset?

Vehicle History https://www.vehiclehistory.com > questions > how-do-...
To reset the anti-theft system in your 2003 cadillac cts depress the key fob's panic button for five seconds before pressing the lock button twice standing ...
2 answers · Top answer: To reset the alarm on the 2003 Cadillac CTS You have two options. You can pop the hood and disconnect the positive battery cable, then leave it off for ... People also ask
How do I get my Cadillac out of anti-theft mode?"

Look for a button that allows you to slide the physical key out of the fob. Step 2: Turn the vehicle key to unlock the car door without releasing it. Hold the key for 30 seconds in this position. This will signal to your car's system that you have the right key, and will enable you to bypass your car's alarm system.

Have your dealer or a qualified Cadillac mechanic check the anti-theft system and your key. Your ECM may need to be re-flashed, but have a diagnostic scan performed to determine possible solutions.

Battery voltage is definitely and issue. Charge your battery and have it tested before condemning the starter.

How to change a fuel filter on a 2003 Cadillac CTS - YouTube

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https://www.youtube.com/watch?v=SRI7SPzVzvk
Jun 2, 2014 - Uploaded by 2LateIWon
How to change a fuel filter on a 2003 Cadillac CTS. ... Lately... my 2007 cadillac CTS (just hit 100,000 miles) tends to shake for may a second if ...

during colder weather, the oil will be somewhat sluggish until it warms up, you may want to change to a thinner viscosity oil during the colder months of the year.

Don't do that again! You will need to re-boot the on board computer system by entering a code. Call your nearest Cadillac dealer.

If you need further help, reach me via phone at https://www.6ya.com/expert/lloyd_4256582adacd68ee

Thinking you have a pass lock problem. In the ignition key and tumbler,
all I can do is send you to the dealer ,watch the security light,it's actions will help diagnose the
trouble . My money is on the Ign. switch

My 2003 CTS would not start on the first, second or third try after filling the gas tank. Finally after several months of this occuring every two weeks a check engine light came on. It was the evac purge valve. Tom

Check neutral safety switch and security system

Are your power seats working? Mine shorted out and several days later my battery was dead because the short was drawing power from the battery when the car was not running. If your battery and charging system check out o.k, I would say you have some kind of parasitic drain on your battery.