Hello I have a 2003 Prius with a hard falt code of P3000 main battery bad! But there is not anything wrong with the batt or how it runs. I cleared the code and in 10 miles or so it comes right back? I was thinking of a reflash on the computer but has anyone had this problem and what did you do?
This can be a can of worms. I'd not think that reflashing the battery ECU would help. Do you have a code reader that will read the sub-codes? I'm also fighting a P3000.. In my research the problem may, or may not be a problem with the HV traction battery. The manual tells me that there's a problem with the HV battery. Here are the areas that the manual centers on if you've got a sub code: HV Battery System High Voltage Fuse Power Cable HV Battery Cooling System I've now been able to define that the problem is a P3009 error. That's a problem with leakage to ground from The HV battery, or The HV battery cables, or the Electric Motor All I have to do now is narrow it down. I'm hoping it's leakage in the battery and I can clean up the terminals and get some more life out of it. I'm still doing more research on this to narrow it down further... I do have a 2nd problem that the auxiliary 12 volt battery dies if the car is not driven every day. The battery is new, and it is good. I've two 2002 Prii that I can swap the batteries to see if the symptoms follow the battery. The problem does not swap to the other car, so the battery is good and the car has a parasitic drain.
