Reason two: have to firstly turn on the Ignition Switch, then plug ps100 into the obd socket to test. Some car's models supply not enough voltage, if you firstly connect PS100 scanner then to turn on the Ignition Switch, it will cause your car supply not enough voltage temporarily, so PS100 scanner display screen will display abnormaly, which will broken PS100 scanner.
Conclusion: If you operate ps100 scanner as I mention above, I suggest you chang a another car, maybe PS100 scanner will not work with this car model.