Which program do you use to test the HV Battery without digging the battery out and test it physically? With some instruction would be nice. I have 2008 model. Can I upgrade the battery to Gen III? thank you.
Your Prius will detect any serious HV battery problem and light up the dashboard if one is found. You can use a good OBD2 tester (Toyota Techstream, ScanGauge (with appropriate xGauge), or a Prius specific OBD2 (Pridash, Torque, search this site) ) to read out the 14 module pair voltages and series resistances to look for the beginnings of divergence. You can upgrade the 28 modules to Gen3 in your Gen2 HV battery case (a good idea if you have a failure), but I would doubt that a Gen3 Battery would be a drop-in. JeffD
