I hooked up a diagnostics to my 2002 Cadillac and now it won't start

hook up a scanner for codes and diagnostic information

I like some of these answers these people post , I believe people need an want to have a little more info then that ! The guy can't even spell ! Neads -- needs diagnostic done on it , an what kind of diagnostics does it need ? Well lets see if I can shed some light on the situation ! I worked at a Cadillac dealership back in the late 80's . The climate control panel is electronic an is hooked up to the BCM - body control module another electronic control module an when operating as designed they communicate info back an forth but yours is dead an the BCM isn't see any info . an the BCM has the function of the security system probably too . An it won't let it start ! Your probably going to need a new climate control head ! This system is connected to diagnostics it's self , if you push the off an warmer buttons at the same time it will go into diagnostic mode an show codes , an do on vehicle self test . With out the service manual you can't do it yourself !

timing is not adjustable on cadillacs,you need to hook up a scanner and check for codes or use the control panel on your dash to pull codes,good luck.

When a transmission slips- it already has internal
damage & you driving it that way, leaves only one option

A $4,000 rebuild

Then maybe more diagnostics, to find out what started all that

Being a 2002 --it is well worn out anyway

If you failed to change the fluid every 2 or 3 years since new

That maybe why it failed also,most common reason for trans
failure

It could be a bad alternator not keeping the battery charged. You need to check the starting and charging systems with diagnostic meters to find the problem.

according what you say i didn't know what happened to your car,
and i think you should make diagnostic and i think you should buy a diagnostic tool or you can do it in a garage.
if you want to buy a diagnostic tool you can click here: xcardiag.com

fuel pressure regulator or fuel pump could be your answer

drop tank change sending unit,check for bad ground,bad gauge,most likely its sending unit bad

If your check engine light is on take the car to an auto parts store like Advance or Auto Zone they can hook up a diagnostic reader for free and tell you what kind of trouble codes are stored in the car's computer. Sounds like you may have a vacuum leak or need to replace your mass air flow sensor.

if no obd ll or no power up check power/fuses and cables to computer if getting power good chance computer cooked