Apple Hardware Test error: 4M0T/1/40000002: 0DD

4M0T/1/40000002
this code is usually something to do with either a fan or even logic board. The 0DD I haven't seen an error code with this ending, usually PS.
Is there any other evidence that you have noticed about the iMac apart from this hardware test.
If it's a faulty fan or logic-board you will need to inform Apple about this error code in your hardware test. ASAP.

Have you done another hardware test since and does it still show the same result, if it does, then my suggestion is simply to ring apple support and inform them of your findings.

The reason I ask what other evidence you have is because Apple will normally ask you. The hotness on top or slow playing games might be or not related, as quite a few with the new iMacs are also having these two issues of hotness and glitches in their games your having.

Turn off the iMac and leave it off for a while until it cools down, then start it up and run the test and see what it states.

I haven't seen the 0DD lettering before, I can only assume that possible it means 0 = zero which is normally the number for your Hard drive and DD is Disk Drive, I can only assume that the 0DD is to do with a fault with your Hard drive, but that's just a guess on my part.

Here is a couple of links that you requested in which the Hardware code has been discussed before.

http://discussions.apple.com/thread.jspa?messageID=5410006&#5410006
http://discussions.apple.com/thread.jspa?messageID=2131905
http://discussions.apple.com/thread.jspa?messageID=5228061&#5228061
http://discussions.apple.com/thread.jspa?messageID=5180071&#5180071

Apple will inform you what the fault is and what the next step for you to do.

Quake 4 demo and Battlefield demo for something like 20 minutes each and, 
when I selected to exit the game, the screen got black for a long time, 
than something weird appeared and the system crashed.

There is definitely something not right with your system. However quite a few people in the discussion forum are having issues when they play intensive games, you are not alone on this. There is a possibility that there is relation with your hardware test, however it could be anything from hardware to even software. If it's software then it's bug, which Apple will have to resolve in a patch.
If it's hardware then it's working out exactly what is the problem, from graphics, to fans, CPU, memory, Hard disk and so on.

You should not have to put up with "toc, toc" noises coming from a new iMac, there does seems to be a problem that needs resolving. Inform Apple what you have done since and let them know about these noises you are experiencing.

Take a look at these two links, because others have complained about noises in the bottom right hand corner and they are trying to establish if it's the fan.

http://discussions.apple.com/thread.jspa?messageID=5604026&#5604026
http://discussions.apple.com/thread.jspa?messageID=5431115&#5431115

I dont know if this is related, so sorry if im wasting time here, But..
If you use smc fan control on these news iMacs. It shows 3 fan speed areas. HD, CPU & ODD. I never knew what this ODD thing was?

If you haven't already done so, then as pop has suggested run smc fan control and see what results you get.
http://homepage.mac.com/holtmann/eidac/software/smcfancontrol2/index.html

Pop! wrote:
I dont know if this is related, so sorry if im wasting time here, But..
If you use smc fan control on these news iMacs. It shows 3 fan speed areas. HD, CPU & ODD. I never knew what this ODD thing was?

ODD stands for Optical Disc Drive. It may be different from the 0DD (zero DD) code the original poster is getting though.

Not sure. What happens when you put a disc in the drive? Does the fan spin up?

Sorry for taking so long to reply. If the fan doesn't spin up when you insert a disc, then there may well be a problem with it. You should take your computer to Apple or an Authorized Service Provider for repair (don't forget to let them know about the Harware Test and the error message) 😉