My 1999 GS300 is currently finding problems to start after replacing the engine. Im trying to hook up a OBD II Scanner to see if it shows any codes but its just saying "Unable to connect with vehicle".......Any ideas what it could be, do i need another type of CAN OBD II(if there is one)!!!????

As long as you have a OBD11 for europe and your car is not a jap import you should be fine.Try the code reader on another car to see if it works o.k? Like i said before,the only time i have come across this is when a fuse has been blown,have you checked? you can easy blow a fuse putting an engine in.trapped wires ect.Hope this helps

as said check it on another car - i had somth similar but i was using the wrong USB port so had to play around with some settings before it would work

yeah tried the obd ii reader in my dads car and it worked fine, checked all fuses and there all ok. I even replaced the obd one just in case their was a crack in fuse that wasn't visable. Their is definatly power to the obd port as the reader lights up, just doesnt want to link with vehicle. My lexus is a uk spec. Any other ideas what it could be??

still sounds like you have not get everything connected back up. Either that or your ECU has gone belly up.

So you have an EOBD11 reader? you can still use a check wire on the plug under the bonnet,i think it is tc and e1(not 100%)if you put a wire between them with the ing turned on the e.m.l will flash to give you codes.

I had the same issue with my 1999 GS. The code reader worked fine in a 99 IS200, but not on my GS.