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P3000 High Voltage Leak advice needed

Discussion in 'Gen 2 Prius Main Forum' started by Jerry G., Dec 5, 2022.

  1. Jerry G.

    Jerry G. Junior Member

    Oct 6, 2014
    Keaau, Hawaii
    2011 Prius
    63A0DC31-0A82-49DF-A3F4-23F00ACDD52D.jpeg 28193576-4B27-4650-B0C1-BAAC8126E318.jpeg Hello fellow Prius’ers. Needing advice on 4 traction batteries.
    I have worked on Gen1 and Gen2 Priuses for a number of years now and need expert advice. I have read as many forum threads on this that I could find in my research.

    One battery has strong cells, 7.8-8.1v, with new bussbars and nuts, New sensing wire harness and new (tested used) ECU. Any connections have been cleaned and very thin layer of electrolytic grease applied to aid against corrosion (tropical environment). I am getting P3000 on this battery. I have read about checking for voltage between negative terminal and metal case and electrolyte leaking through mounting threads and a epoxy fix. My concern is reading voltage at relay terminals and case, I get 84vdc and 64vdc at wire connections. WTH? Am I screwed here? Why is there such high voltage here? What else should I be looking for/checking to isolate the leakage??
  2. mr_guy_mann

    mr_guy_mann Senior Member

    Sep 3, 2020
    2006 Prius
    Ok, a couple things here. One is that P3000 is set by the hybrid control ecu and says "hey, the HV battery ecu set codes". There should be a sub or INF code with the P3000 that can give more details but you should have codes in the battery ecu. What scan tool are you using?

    That said, you shouldn't have any "detectable" voltage potential between the HV system and chassis ground (battery case). Unplug the battery ecu and retest. Then disconnect the leads at the battery for the contactors and retest. I would next remove busbars to isolate some modules into groups. Then test which group still has voltage to ground. Keep dividing and testing until you find which module(s) are leaking. You could have more than one problem, so check everything.

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