2001 dodge stratus2.7 no crank no start

Could be a number of things...starter or solenoid. Starter relay or ignition switch. Battery...whats the lights on dash do when you try to start? Stay on or go off.

Could be a bad starter, but before I pulled it I would check all electrical connections especially the grounds. This sounds like a bad ground to me.

Could be the immobiliser isn't disarming...

I suggest you try to energise the starter solenoid manually and if the engine cranks possible faults are immobiliser, ignition/starter switch, relay, connections, wiring.

If the engine doesn't crank the fault is the starter or solenoid or connections to the battery or starter.

When you use the ignition key you activate both the starter and ignition circuits. When you jump the starter motor all you do is crank the engine - you have not energized the ignition so car will not start.

I had a similar problem years ago. As long as your dash lights come on, it's likely you can use an external pushbutton switch to run the starter. There are likely just 4 wires on the ignition switch. Power from the battery, and switched to:
accessories
main car stuff (dash lights, ignition, signals, etc)
starter.
splice in wires from battery and starter to new switch, and you're good to go. This worked for years on my old car.

Do you have power on the yellow wire from the key switch to the starter relay when the switch is in the start position ?

The battery. Now if the car does not even crank and the starter is good, then I would recommend checking some fuses and relays. Some fuses to check would be the ignition, start, etc. For relays I would check the starter relay and the neutral start relay. I would also check neutral park switch on the transmission. If the switch isnt working properly then the car wont start at all.

If it does not crank check your starter relay, battery and ignition switch.

Check your manual if you have it. I believe you need to have the key in the ignition in the ON position for about 10 minutes to reset the security system.

First thing is to check is the ignition fuse/relay under the hood for a blown fuse or bad relay. If everything is ok then set parking brake with truck in park/netural and have someone to turn the ignition over to start and at the same time use a test light to check for fire at the starter solenoid. If no fire then the ignition switch or netural switch on transmission is causing the problem. If you do have power to the starter solenoid then the problem would be either the solenoid or the starter drive locked up on the flywheel. Be sure to remove the negative wire from the battery if you need to remove the starter. Hope this will help you.