I have a 2007 prius that drives perfectly fine and does not have any trouble codes but as soon as you try to connect a scanner or hook up obd2 for smog, the car shuts off and displays all warning lights and the gear selector begins to flash along with the fuel gauge.
yes that happened to me with on of those cheap ebay techstream dongles. The instant I plugged it in all the warning lights came on and the car would not do anything. Disconnecting the battery reset it but I just tossed that thing in the garbage. I was probably just unlucky and got a bad one, but I didn't want to take any chances, so I have a Lemur "BlueDriver" now and it plays fine with the Prius. Yes I know you can get cheaper devices.
What Jessie said. There's many alternatives to modern obd readers there an Android Torque app and there's a Scangauge for around $160 and theres a mini vci on amazon.com for $30 and theres a plug and play VXDIAG that also has Toyota techstream software. If it has no codes thrown all sensors are happy.
Take it to O'Reillys. They will read your codes for free, and they use Bosch brand code readers. If it happens with their reader, you know it's your car and not the reader.
I assumed he meant no dash lights because he can't possibly know that he doesn't have any codes if he can't use a code reader.
