There is a reset function that should fix that, I thought mine was bad but the Snappy dealer showed me what to do, but that was a couple of years ago and I am suffering from CRS disease.
I use a PP3 on CAN cars every day, no different from older cars, you have to know what you are probing. You can check for activity on serial data circuits, just keep your finger off the button.
Some people just shouldn't be allowed near electrical circuits...I
never loan my Fluke out, one of my co-workers was chasing a draw today and was getting funny readings on the parasitic draw test, I went over and set up my Fluke for him and started the test, all he had to do was check the display and see if there were any current spikes over the course of an hour. He managed to blow the fuse while moving the meter, he said the clamp popped off the test switch and hit the positive terminal...