2000 Cadillac deville I'm driving the car and shut off engine ,also when the car is parking doesn't turn on engine, sometime the engine is working I tried with my 2 keys ,doesn't work .I can't drove a long distance because the car shut off (dash board doesn't show anti thief system)before that i replace the battery was dead..............

SOURCE: 2000 Cadillac Deville DTS is in anti- theft mode

you can reset the system by turning key to on position for 5-10 mins and then try starting it but its probably a short or grounding prob try the engine to chassis ground

SOURCE: 1997 cadillac deville anti theft

This might work for most:

Theft Module Re-learn Procedure without a T5O or T6O
During this procedure, the vehicle battery must maintain a minimum of 10.5 volts. If the battery is not fully charged or is weak, a battery charger may be connected.
NOTE The battery charger must NOT be set in 12 volt boost. This will prevent this procedure from working.
1. Cycle the ignition switch to the "Run" position.
2. Wait a minimum of 10 minutes, cycle the ignition switch to the "Off" position.
3. Cycle the ignition switch to the "Run" position.
4. Wait a minimum of 10 minutes, cycle the ignition switch to the "Off" position.
5. Cycle the ignition switch to the "Run" position.
6. Wait a minimum of 10 minutes, cycle the ignition switch to the "Off" position.
7. Verify the repair.

and if not try this:

STARTING DISABLED/DUE TO THEFT SYSTEM/REMOVE IGNITION KEY"
If the Powertrain Control Module (PCM) does not receive the Fuel Enable message it will use the class 2 serial data line (CKT 1807) to tell the Instrument Panel Cluster (IPC) to display the "STARTING DISABLED/DUE TO THEFT SYSTEM/REMOVE IGNITION KEY" message on the Driver Information Center (DIC) . This will inform the driver of why the engine is not starting. When the ignition is turned "OFF", the IPC will start a timer and display messages to inform the driver to wait for the PASS-Key II timer to run out. The messages will read "WAIT 3 MINUTES", "WAIT 2 MINUTES" (after 1 minutes has passed), "WAIT 1 MINUTE", and "START CAR".
If the timer was not run out, the IPC will not send the Fuel Enable message. When the PCM does not receive the Fuel Enable message, it will command the IPC to re-start the message process.
This message is most likely caused by an improper key resistor value or the IPC did not properly sense the ignition key resistance.
good luck!

SOURCE: just bought a 1998 cadillac DeVille

traction control and brake antilock is coming on what can i do

SOURCE: How can I bypass a anti auto theft system on my 1990 cadillac seville?

I Have A Seville 1990, When That Happen To Me I Got The Inginion
Replaced Problem Solved. What Is Happening Is Your Key Has A Chip And That Chip Is A Resister And When The Valve Is Not Sented To The Computer It Disengages the Fuel Pump And Than Tells You To Wait. Soon All That Will Happen Is You Will Get The Wait 3 Mins And It Will Never Start, A Good Locksmith Can Take Care Of This For You And That Will Save You Some Money. Cause If You Go To The Dealer Ouch They Will Hit You Up. But I Asure This Is How It Will Happen Cause It Is How It Happen To Me
And Sorry There Is No By Passing The Computer

SOURCE: Parking brake stuck.

if you look at the pedal for the emergency brahe there is a small lever that will allow you to by-pass the vacuum operated release,check for vacuum at the hose that goes into the release