i have a cav turbo, and it rattles...
it sounds like a loose exhaust mounting, but ive checked its o.k.
when i brake it stops rattling, foot off the brake rattle again!!
this is why i think it could be the txb...
are my worst fears right??
In my humble opinion, it is likely to be the fuel pipes.
I had the same sort of thing and thought it was the brakes.
The reason it stops, when you brake the inertia will force it forward, making or breaking contact with the bit it's knocking on.
It was in the driver's rear arch area.
You've probly tried this but does the car rattle with fuse 19 out ? be a better simple test to see if the rattle is the tbx than pressing the brake.
I had a rattle like this, turned out to be the heat sink on the cat had a broken fixing at one end.
Good luck locating it, nothing worse than a rattle !
Could easily be the propshaft.
There are a few UJ's on there that can go dry and get squeaky.
Try putting it up on a ramp or 4 axle stands and stick it in first.
If you get right under the car you'll find exactly where the noise is.
Be aware the propshaft is hollow so the noise can travel along it.
Anyway, it's quite good fun simulating wheelspin and watching the tx box react