Why is a P0240 code being read on my 2005 Hundai Elantra GT hatchback?

code p0240 refers to manifold absolute pressure(MAQP) sensor B TC system--range /performance problem===causes---intake/exhaust leak---hose connections--MAP sensor
Check the exhaust system for leaks especially around the manifolds and gaskets. Check all vacuum hoses for leaks. Finally replace the MAP sensor. Run code reader to reset the CPU

Try cleaning and lubricating all the sun roof glass element tracks. Use a light coating of white Lithium grease.

im assuming its an 2001 but ur question says 2012... the cooling fan prolly isnt coming on and if it is...then ur thermostat is stuck closed. does the gauge read hot or do u just notice the engine overheat?

Acura code P0240 - Turbo / super charger boost sensor (B) circuit range performances.

It's is best to take it to a certified repair shop, where they can get actual reading's from your Turbo sensor's.
You don't want to drive it that way it will damage your Turbo and there very $$$..

check right under the rear end of your vehicle body near the fuel lines

You need to have someone hook up a scan tool to access the code(s) to determine what the problem(s) is/are. There is really no other way to solve this problem properly.

Too many possible causes for this. Take it into the dealership and have it properly diagnosed. Sounds to me to be a BCM problem (body control module).

Certainly not good to drive with airbag off, but it may just be a burned out fuse so check your fuse panel(s) for a bad fuse, which will cause light to come on.

Check out this link , has goos description on removal of Dash & Audio.

http://www.carspace.com/guides/2001-06-Hyundai-Elantra-Audio-Guide

look in your cars owners manual