2001 Cadillac DeVille

remove door panel and test the harness

Try getting out of the car, close the door, lock it with the remote.
Then, open the door using the KEY and try to start the car.

Check for codes as with all vehicle issues,every
time any dash light stays lite,nothing new,same
precedure 32 years running

do you mean 'abs'?

The SECURITY light is located on the instrument panel cluster.

If the ignition is off and any door is open, the SECURITY light will flash, reminding you to arm the system. To arm the system, do the following:
1. Open the door.
2. Lock the door using the power door lock switch with the door open or the remote keyless entry transmitter. The SECURITY light should come on and stay on.
3. Close all the doors. The SECURITY light should go off within approximately 30 seconds. If a door or a trunk is opened without a key or a remote keyless entry transmitter, the horn will sound and the lamps will flash for about 30 seconds.

Also can check this and other details in the 2002 Cadillac Owners Manual (page 85 and next).

Hope helps (remember rated and comment this).

Replace that relay for that is at fault

I have had the same problem and I have come to the conclusion it is the security system. After 3 minutes the car will start so there is nothing wrong with the battery or starter. I have had it to the dealer a few times and they cannot solve it. It may be the locks on the doors and they may not be resetting properly. I have learned to live with it.

1-insert and remove key from ignition two times

2-close and open driver door two times

3-insert and remove key once from ign.

4-close and open drvr door twice

5-insert key into ign.,then close driver door

6-turn key to on (not start) then off, twice this is rewrite mode,have all remotes to reprogram it will clear any lost remotes.

7-remove key from ignition,the door locks should cycle twice.if not start over.it may take a few tries.

8-press lock/unlock together and hold for a second

9-release,and press lock on remote,the door locks will cycle confirming program.continue to do other remotes you have,steps 8 and 9.if only one in possession,you are done. To end mode open door or insert key into ignition.

You'll need to follow the steps with no more than a 1-2 second delay between each step.. hope it works

You need to turn steering wheel the same direction as the wheels are turned. When you turned the wheel quickly you were holding the wheel when you turned key to lock position and when you let go of the steering wheel it wants to go back the other direction so it is real tight against the lock.

I am having the smae problem starting this week. Key fob has been broken for several months (and on a 2001 Cadillac you HAVE to go to dealer to program a new one.) So I've been using the key-- no problem.
FIrst thing others need to understand. The 2001 Deville has a key entry on the Driver's door ONLY-- not any other door. So you can't just go to anotger door.
Secondly-- I am trying my 'main' key, which admittedly has some wear. But I am also trying my "spare" key which has practically no wear at all-- so this is not an issue of a worn-out key. Both have worked fine in the past.

What happens is that the door lock all of a sudden will not let the key go all the way into the lock. YOu can feel it being stopped for the last 1/8 of an inch or so-- just enough so you can't turn the key in the door lock. Seems like some kind of messed up security feature. But all I know is I cannot get into my car, parked in my garage!