DTC information display on XC70 2007

[Danhere]

Is it possible for some one unscrupulous to deactivate the DTC message display?

I Just got hold of this XC70 2007, car dealer said they got the garage to clear the faults.
Been trying to do the code check with the stalk and light button but its displaying nothing at all, i can see it very dimly illuminating in the back ground but screen wont display any messages at all.

Car is running fine, hasnt gone into limp mode or anything, fresh mot registered online but im worried they have some how disabled the display window to hide any remaining faults.

My own garage said they shouldnt be able to hide warning messages but something isnt right as the particular screen is showing nothing at all.

My garage was too busy to plug it in, although that was my first port of call. To go get the fault codes read.