More Details on Xbox360 Error Codes

I noticed nobody has posted the reasons for visual error codes so I figured I'd put out what I know. A lot of these errors can be the results of any number of problems, especially with something like E74. So take these with a grain of salt. The explanation "general hardware failure" is an acceptable description for most of these because you would have to specifically look at each board to see what went wrong, but this might help with a few trivial errors, or help people pinpoint problem areas.

E64 - Dvd drive timed out during reset
E65 - Dvd drive is not DMA configured
E66 - Dvd drive pairing failure
E67 - Hard drive timed out during reset
E68 - Hard drive not DMA configured
E69 - Reading the HD Security sector failed
E70 - Hard drive not found
E71 - Error within Xam
E72 - Error within Xam
E73 - Couldn't calibrate HSIO Bus from edram
E74 - HSIO related, could be crc error, or many things.
E75 - Ethernet - Couldn't read ethernet phy vendor
E75 - Ethernet - wrong ethernet vendor
E76 - Ethernet - Couldn't complete ethernet reset
E77 - Ethernet - phy request is already processing
E77 - Ethernet - reading reg failed
E77 - Ethernet - Failed to write reg
E78 - AsicId check failed
E79 - Couldn't start xam.xex
E80 - Wrong LDV version

The secondary error codes work as follows. Each blinking field represents 2 bits of an 8 bit hex value, or 1 byte. This byte being the "E" error code.

1 blinking field = 01
2 blinking fields = 10
3 blinking fields = 11
4 blinking fields = 00

For example, an led field sequence of 1031(crappy naming method) that some people have posted. It should really be be 1431 (that other method of naming is annoying). This means our 8 bit error code is 01001101 which when converted to hexadecimal becomes 0x4D and then to decimal as 77. so, 1031 is E77. So do the same method as before holding sync and pressing eject to get your secondary code, convert each to the proper bits, and then convert those to decimal, and you'll have your "E" error code. Hopefully this will help some people stuck with 3rods out of warranty and nothing displaying on screen to see what's wrong. Thanks to Tmbinc and redline99 for their help.

http://www.xboxhacker.net/index.php?topic=11779.0