ive used this on many cars, since the tool was first sold. I Love it.No it don't work on all cars.(no scan on earth tool does !!!!) but all 96+ cars it does.it works on my C.A.N buss 04 grand vitara. and my 96 Mazda and  and 99 Mazdaand 2 Geo trackers (sidekicks)  96/97 and others,  vast numbers..if your car is older than that?, then it don't comply to obd2 standards.?then it has no chance of working!!! (same with other makers of 0bd2 tools!!)there are exceptions,some 94 Fords,have OBD2 and scans perfectly.some 94 Toyota's toolTruth of it:it don't work, until the unit has it's battery good, and is plugged in to carand the key is turn on ,, in the car, with no communications, it can't work.  sorry, but that is a fact.  The 2 chips end to end need power to work and talk.before condemning it, try 2 cars, 96+  (it fill work )1996 and newer....it only reads EPA codes, P0xxx and never, factory codes P1,(unless lucky)mine reads P17xx factory tranny codes. (nicely but not on all cars)P0xx DTC codes and PIDS, are federal codes,  (basic to all cars here) 96+it's a federal rules scanner ONLY, you will never see a tool that gets all carsand all factory codes, no P1xxx  or p2xxxx. for cheap. $5000 yes.with a box full of plugin for $300 each.  but not for $50ever,, go to  [i cant post other linkings so search OBD2 tools....]it does not do ABS either. sorry.  (it does have lots of bang for the buck)you do not need windows 7 for it to work, in fact,the tool works all by itself.it has a nice graphic mode.  unlike! any other tool! for this price.!for that, i give it 100 points.  (im ASE and have 5 tools of many  brands)since it reads all the federal PIDS/DTCS only, it dont need to be updatedafter all that has been the same for 17 long years, unchanged.updates?, what a wild idea.?the doc.s are weak but what do you expect for $50 from china.I love mine.i plug it , scan and it done,, i use mine alot in graphic mode.the 02 sensors,or MAF,or MAP.  excels at that for low pricethe guy who posted, it shows 2 Dtc'S BUT LISTS, 1Reasons.1:on Fed code and 1 hidden factory code.2: code P0400 which is 2 codes, 400a and b, see pending for a or b.3: its intermittent.  (marginal failure. so use pendings to see them)the scans are long.so by the end,, maybe the DTC cleared but for the next scan.do be too critical, just trust the DTCs shorted, or pending.EFI is not digital nor  is the engine,it is analog.things can fail and clear fast.  its you job to be patient and watch.eg:lets say the idle switch is on the hairy edge. so the code comes and goesrandomly with engine shaking it.... see?some ECUs are slow to scan than others. the tool can not correct that.no tool can.happy scanning.