If you can, please point us to an example code which you have trouble scanning for reference (or upload a picture of one).
Else … Which App gives you trouble with the scanning?
It’s not the camera hardware that does the scanning.
There are barcode or QR code reading Apps which get the picture from the camera and then look for codes they can recognize and read in it.
Or such functionality can be an embedded feature of Apps which just need to read barcodes or QR codes as part of whatever else they do.
That said … code scanning relies on focus. If the focus mechanism of the camera would be broken, code scanning could get troublesome …
Also, damage or scratches on the camera could blur the picture, making code scanning difficult.
Does your camera work allright for photos in general?