My 2005 Cadillac started jerking and then it stopped moving. What is wrong with it?

Question edited for clarity.
Question moved to model category.

Cadillac DTS (2005-2011) fuses and relays

Fuse Box Diagrams https://fuse-box.info > cadillac > cadillac-dts-2005-20...

Fuse box diagram (location and assignment of electrical fuses and relays) for Cadillac DTS (2005, 2006, 2007, 2008, 2009, 2010, 2011).

Some ideas here, but most deal with NO crank, no start.

https://www.google.com/search?q=2006+Cadillac+DTS+crank+no+start

It is a highly complex vehicle, you need an auto electrician with a pro grade scan tool computer to diagnose what electrics aren't working

https://www.google.com/search?q=mobile+auto+electrician+near+me

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just to take a guess with the information you gave I would guess maybe the Map or Mass sensor could be bad,but you should get it analysed first to make sure.

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 fluid can be low.

It sounds like the firing order may be off. Make sure that you re-connected the ignition wires in the correct sequence.

Solution No

Only checking for codes & with or without them,
some testing has to take place

sounds like your tranny neeeds flushed, everything in that auto tranny is moved by the transmission itself, there are electronic valves that open and close to make things move but all they do is allow high pressure tranny fluid to push other things around. there is a lot going on in there, usually when the fluid gets bad or low or old the first thing is the govenor of the transmission will start acting up. check the level and the color. besure to read how to check the level, some times you have to have a warm tranny and running. other times not. also the color should be almost a clear pink, if its red or worse a dark red, get it flushed

replace park neutral switch located beside the shift cable

dear friend-it sounds like the drivetrain packed up,it is possibly the diff that broke and jammed the drivetrain.

fuel fiter or fuel pump may just need a tune up