from new my 2010 GUDX was a pain with the cruise control!
It would work great or would set but not work.
I tried all things possible (other than applying the brakes) swithch off cruise, swith off engine re start engine, re set cruise all to no avail seemed to have a mind of it's own.
Then I saw on a different thread THE ANSWER = *YOU MUST APPLY THE BRAKES TO ALLOW CRUISE TO OPERATE*, no more problems every time the cruise won't work I touch the brakes and like magic the cruise works, seems a little man in the engine ECU is verry worried that the brakes might not work, so you can't set cruise untill you have tested them,
Regards
Joe
seems he is then happy (dosent prove you can stop though!)
2010 GUDX custom Dual cab chassis 4.8 brakes 3.6T GVM, front locker, 33"mud tyres