My aunt gave me a 2005 Prius after her brother passed... This car has been sitting in a field at the edge of the woods for 5 years. We installed a new 12v battery and gave it a bath. It runs but has many warning lights on. Scan car with Autel MX808 P0AFA B2775 C1259 C1310 P0A08 P3000 HV battery Block 1 voltage keeps flipping +16.2 to - 16.2. (positive to negative) I have pulled and cleaned the HV sensing wire (block 1) + sensing wire harness plug & HV ECU. I also took the HV ECU to my local electronics shop for plug corrosion inspection & clean up. I have cleaned up the HV pack terminals, nuts, sensing wire terminals, and bus plates for the battery blocks and this far no change. How best to troubleshoot Block 1 voltage issue? Can I swap block 1 & block 2 sensing wires? If the problem moves then HV ECU or harness / if stays then bad block or cell.
You have a problem in the sensor harness, plug or ecu/ecu socket. You can purchase a new sensor harness from Toyota for about $65.
Is "HV ECU" the ECU you really mean here? The battery ECU is inside the traction battery; the HV ECU is behind the glove box, in the dash. (The "HV" in "HV ECU" stands for hybrid vehicle, not high voltage.)
Don't be surprised if sections of the wiring harnesses have been chewed down to bare wires. There is just no way that a car sitting in a field that long hasn't been home to many generations of rodents. For instance, that headlight looks like a rodents nest. Don't turn on the headlights! If by some miracle that bulb is still intact and the wiring is good the heat might start a fire inside the housing. Check the top of the thermos bottle - some furry creature stored a bunch of acorns there in my car when it belonged to a previous owner.
You can get it working but it will take time, effort, money. Or some combination of the above. Car prices are crazy high so I’d say it’s worth it. Your starting price of zero helps. Good luck. A few helpful tools and pieces of equipment, sorting the good, experienced, knowledgeable advice from the opinions on PriusChat and you’re on the way.
Whitfimb, If you need the repair manual for your 2005 Prius, send me a PM and I'll reply with a link to download it from my web site. JeffD
Thanks! The large 2 volume set of Toyota Prius manuals came with the car. New voltage sensing harness from Toyota installed - this came with 2 large battery leads wires from each end of the battery bank to the solenoids. Meanwhile my Autel updated and I can no longer see individual battery cell voltage.
A friend recently gave me one of these fancy Hybrid battery testers. I might have to see what this magic 8-ball says. I believe I have a battery cell issue and a dc/dc inverter signal issue. It will take some time for me to navigate my way to the proper pin out locations for 591 (the HV and inverter plugs)
