I have a Falcon
Its in quite a small area so runs quite hot
but has been happy with this for 3 years

Its never been opened
Last week it had two red lights

I repasted the gpu
heat transfer isnt a problem as the heatpipe is boiling

The fans sounded normal

Ayway it was still having two red lights

Last night i did it again
and also did the cpu this time

Its transfering the heat just fine

but after a few hours of a game it two red lights
if the central heating is on

on looking into this deeper the fan speed isnt ramping up
when playing games

So i dont think its a problem with the heatsink's at all
rather the fans not being sped up

has anyone ever run into this?

I checked the secondary error code its 0013

I also tried jamming the fans
to force an overheat to see if the fans would ramp
in that case the fans did ramp up like mad on turning back on
for a good 15 seconds

I was able to find three links in this forum relating to your issue:

http://forums.xbox-scene.com/index.php?showtopic=642290
http://forums.xbox-scene.com/index.php?showtopic=718037
http://forums.xbox-scene.com/index.php?showtopic=691027

From other forums as well, it sounds as though this is a common issue relating to MOSFET.

Just after i got the error 0013 code out of the xbox
I read up on it and most people seem to think its a cracked joint on a ram module

I have just spend the last hour or two stripping the console and masking off everything apart from the ram

I esp made sure to keep heat totally away from the gpu
as the epoxy'd down gpu's i have never had much luck with

anyway i heat gunned the ram modules for around 4-5 mins low temp 1-2 mins high per board side

Its been sitting in a private match in black op's for around 60mins

will post back if its a fix or not

for other people if they ever get this problem

Looks like it was a ram problem

Black op's played all night
and its been on all day playing mass effect 3
no problems yet

Awesome! Glad you were able to figure it out and haven't come across any issues yet. Thanks for updating, I was quite curious myself. Looks like those error codes do help out once in a while.