580EX II Problems on 1DMkII...

When i have the 580EX MkII mounted on my 1DMkII the flash often sends itself into TTL mode rather then ETTL mode. Firstly, what does TTL mean? When i take the flash on and off and turn it on and off a few times its back to ETTL. Just wondering if a there is a problem with just my set or would a 430EX or 580EX (Mk1) or 550EX would fix this?

Dirty contacts possibly? I got this using a ETTL chord once. Turned flash off and camera then btoh back on and it was fine. Just make sure all contacts on flash and camera are clean.

TTL was found on older cameras. Try it out on a different body if possible to see if it still keeps happening. Will help to narrow down on whats causing it.

Have a look at this thread. https://photography-on-the.net/forum/showthre​ad.php?t=533020

With the flash locked into the hot shoe, can you wiggle or rock the unit? Often times the camera hot shoe gets loose, and tightening the flash actually lifts the flash against the hot shoe rails which will then lift up one or more contacts, causing the flash to lose the eTTL function and go into TTL mode.

You can test this by unlocking the flash, and pressing the flash vertically down into the camera hot shoe, and then turn the flash on, and it will likely be in eTTL mode. Moving the flash around in the hot shoe it should become obvious when the contact is lost, and the display switches from eTTL to TTL.

To tighten the hot shoe, you need to remove the spring plate first:
You have to slide a pointed blade (hobby knife) under the spring plate from the back, and break the cement seal that is usually up at the front edge. Lift the front edge of the spring plate slightly so it just clears the front edge, and slide it off towards the back.

Tighten all 4 of the little screws, even using a drop of threadlocker very carefully. Put a drop of cement up near the front edge, and slide the spring plate back in from the rear, making sure it clips into place over the front edge of the hot shoe itself. Put any device into the hot shoe to put pressure on the spring plate until the cement dries.

Nope, When i put it in there is NO play at all.