On my 97 dodge neon i did a code check by turning the key on off on off on and came up with 3. 12, 43, 27. Could someone tell me what those are?

SOURCE: key stuck in ignition

try turning the steering wheel either way at the same time that you try to get the key out

SOURCE: key stuck in ignition

Take the steering column cover off and tap/hit the ignition barrel with suitable tool (small hammer)while twisting on key.It may be enough to loosen it so key comes out.You will have to remove steering column cover to swap with replacment barrel anyway .Get someone to turn steering wheel while tapping/hitting barrel as it could be the steering column lock pin thats jamming.good luck.

SOURCE: Dodge Neon code 1494

p1494 isnt for the purge solenoid it is for a mechanical switch failure detected in the leak detection pump. as long as the pump has vacuum going to it the likely cause is the pump itself. it is attached to the vapor canister

SOURCE: My Dodge Neon Engine light

you have to replace the oxigen sensor on the exaust

SOURCE: what is code 1494 mean for 2001 dodge neon

P1494 Leak Detection Pump Switch or Mechanical Fault
Part of the early evaporative emission system. (Fuel tank fumes)

It’s there to allow the computer to run an integrity test of the fuel tank, lines and carbon canister’s ability to contain all of the fumes coming from the tank and all line associated with the system.
The code could be set for a number of reasons such as a faulty gas cap, cracked vacuum lines, solenoids & vent valves stuck to the pump itself.
It can be a very difficult fault to cure being it doesn’t take a very big leak anywhere in the system to set the code and that’s if it’s a leak and not an electrical or mechanical fault.