Car won't start but all electronics turn on - 2003 Cadillac CTS

You said that you replaced the battery so in either case of new or another battery have a load test done as what you describe indicates a failing cell in the battery or loose t/dirty terminals.

Your battery is shot.

The 1st thing that MUST be done is to have the electronic engine control system computer (called the "PCM") scanned for fault codes, this gives you the starting point for diagnosis od why the warning/fault light is on. You can get the scan for fault codes done for free at any Autozone or similar discount auto parts store in your area. Aamco Transmission does the scan for free as well.

Hi there !

I won't say its an alternator problem because the alternator only charges the battery when its on, And it should start with the jump cables even if the battery and the alternator are bad. your Issue is not clear. Does the car start when you jump it ?

Have you checked the timing belt ?'if that appears ok then check the ignition module which this older vehicle would have.

electronic key on 2008 jeep cherokee says key damaged or key not programmed. car won't start. some things work but radio won't come on. etc..

Hello,
Just a simple hint. Just try reset ECU that will fix the problem if its a minor related to electronic.
Still wont start means you need to go to shop to get curbed .
Thanks

Have the charging system, battery and the starter checked. If the battery is weak it won't be able to supply enough power to turn the engine over and power the other electronics at the same time. The same is true if the starter draws too much power. When you jump it you are giving enough power to overcome the problem, this will come to the point that it won't start at all.

you said you repl dist cap that means you don't have a crank sensor you have electronic ing module. remove your elec ing module have it tested most auto parts stores could test your module, or check your coil at the neg terminal. should have power. if not you lost your primary volt from your batt.your secondary power is coming from your electronic ing module from the module to the pos terminal on the coil, when the eng cranks,from the coil to the dist cap , from the dist cap center to the rotor then out to the plugs,this all happen pervided the timing belt or timing chain is ok. the cumbustion chainber needs 3 things , thats fuel, air, and spark.

Does it turn over? If not, try disconnecting the battery and reconnecting it. This has worked for my Jeep before.