Did you search the forums for P3017? I'll bet it is already answered. For example: Classic Hybrid Battery Gone "Bad" | PriusChat Did I kill my main battery ??? !!! | PriusChat 2001 Prius DTC Codes P3000, P3006, P3016, C1202, C1259 | PriusChat DTC codes pdf http://priuschat.com/attachments/2010-prius-dtc-codes-pdf.33416/ Read this: Predictive battery failure analysis for the Prius Hybrid Installing a Prius HV Battery