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Hybrid System Warning Lights - Need Clarification

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by TheNewGuy, Jun 3, 2018.

  1. TheNewGuy

    TheNewGuy New Member

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    Good morning/afternoon/evening to you all. As the name of this thread implies, I’m in a bit of a pickle.

    I own a 2005 Prius with 275200 miles on it. Yesterday, I was driving this car without incident or signs of disrepair. I’ve been religious in changing the oil and oil filters on this vehicle, and other than maybe needing some break work soonish, I’ve treated this car like a jewel.

    I woke up this afternoon to drive to my Sunday service, if you will, and was greeted with the following:

    upload_2018-6-3_21-0-29.jpeg
    upload_2018-6-3_21-0-48.jpeg

    As I mentioned before, I pay very close attention to this vehicle and do all I can to stay on top of repairs. This literally happened overnight. Currently, I’ve attempted to replace the 12V battery (the small one located in the trunk of the hatchback), but it didn’t work. I wasn’t sure if I need to wait and give the battery some time or if this is the dreaded dead cell in my Hybrid Battery. I would note that, based on my Energy display, the Hybrid battery seems to be holding at a steady charge, but the engine will not turn over.
     

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  2. bisco

    bisco cookie crumbler

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    more likely the hybrid battery at your age and miles. does the car become ready? you will have to have the trouble codes read to confirm.
     
  3. ChapmanF

    ChapmanF Senior Member

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    What he said. You've got the lights on your dash that tell you something is wrong with your car. That's it. Out of the blue, so you don't have any other symptoms to hint at which of the couple hundred possibilities that might be, either. We'll be getting somewhere when you read the reported information from the computers that turned those lights on.

    -Chap
     
  4. Wayne

    Wayne Active Member

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    I third that. That's at least 2 more lights than my bad 2005 hybrid battery generated. Also, I can still drive my bad battery car.
     
  5. TheNewGuy

    TheNewGuy New Member

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    Thank you all very much for replying. I was admittedly expecting that I would need to get some codes, which I will hopefully be able to provide tomorrow. To answer the question that was posed, no, the system won’t go into “ready” mode, and it won’t let me shift the car out of park, not even into neutral.
     
  6. edthefox5

    edthefox5 Senior Member

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    When you have the red triangle of death accompanied by the car icon on the mfd pretty much confirms its the hybrid battery.

    You can have it towed to the dealer so they can confirm it dealer will charge $150 diag fee + your tow back and forth or you can buy an obd code reader off amazon a read it yourself that has the proprietary software and works with a laptop. Its called VXDIAG with techstream software for toyota. the tech stream is the toyota repair software thats needed to read all the hybrid codes including the inf codes. $99.

    An obd with techstream is pretty much a necessity if you own a G2.
     
  7. bisco

    bisco cookie crumbler

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    if it won't go ready, you need to test the 12v and connections.
     
  8. TheNewGuy

    TheNewGuy New Member

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    Alright, so I just had my mechanic read my codes. We actually only found two, which is somewhat comforting and concerning at the same time:

    C-1259 (or C1259)
    C-1310 (or C1310)

    At this point, I'm pretty certain it's either a dead cell in the battery or possibly an issue with a connector. Thoughts?
     
  9. edthefox5

    edthefox5 Senior Member

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    C1310 is usually a bad inverter coolant pump. With car in READY open the inverter coolant reservoir and look inside it and look for current flow like its being pumped. If the coolant just sits there you have a dead inverter pump.
     
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  10. TheNewGuy

    TheNewGuy New Member

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    Understood, though the car won't get into READY status to begin with in its current state. My mechanic said that the 1310 code may simply be a byproduct of whatever the 1295 code is signaling to.
     
  11. edthefox5

    edthefox5 Senior Member

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    The pump may have shorted out and blown a fuse. Check all the fuses in the box under the hood and in the drivers side kick panel.
     
  12. TheNewGuy

    TheNewGuy New Member

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    Okay, so an update. My mechanic took the hybrid battery out of my vehicle and checked each of the cells, which all are reading between 7.4v and 7.6v. The cells are clean with minimal corrosion. He swapped out both my ECU and my power inverter with a known good ECU and power inverter and attempted to restart the car with no luck. Considering that the vehicle has a new power inverter, if it were an issue with the inverter coolant pump, it wouldn't prevent the engine from turning over if the fried inverter was replaced with a new one, right? We've already eliminated the brake control box as a potential component since it wouldn't prevent the engine from turning it over even if it went bad. We've eliminated the possibility of a dead or weak cell since the battery wasn't at full charge when the engine stopped turning over anyways. We've eliminated the ECU and power inverter as an issue by swapping those components out with known good components. My mechanic and I are wracking our brains for any other potential issues that could cause this day-and-night change in the vehicle functioning. Is there something else that I'm missing?
     
  13. TheNewGuy

    TheNewGuy New Member

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    Additional update: my mechanic is suspecting that it is not the HV battery ECU that is the issue, but rather the HV control ECU, one of the computers located behind the dash. Before installing this component, does it need to be flashed to my current vehicle, or can it be installed as is so long as it falls within the Gen 2 Prius line?
     
  14. TheNewGuy

    TheNewGuy New Member

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    Hey, thank you for responding to my post. I found out that the scanner that my personal mechanic was using wasn't up to snuff to pull the P0 codes. He consulted with a fellow mechanic who was able to put a more advanced scanner to the vehicle. Here are the codes he pulled up:

    C1203 - Engine Control System Communication Circuit
    C1241 - Low Battery Positive Voltage or Abnormally High Battery Positive Voltage
    C1259 - HV System Regenerative Malfunction
    C1310 - HV System Malfunction
    C1345 - Not Learning Linear Valve Offset

    P0a40 - Drive Motor "A" Position Sensor Circuit Range/Performance
    P0a41 - Drive Motor "A" Position Sensor Circuit Low
    P0a4b - Generator Position Sensor Circuit

    We were thinking all this time that the problem lie within the hybrid battery or one of the ECUs. How far off were we?
     
  15. edthefox5

    edthefox5 Senior Member

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    Your right on.

    Also your 12 volt battery is toast too which sometimes muddys the diagnostic waters. It’s hard for the ecu’s to report correctly when there own power is sketchy.
     
  16. bisco

    bisco cookie crumbler

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    i still think you should check the 12v health.
     
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  17. TMR-JWAP

    TMR-JWAP Senior Member

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    On a side note, to eliminate any confusion, the car does not need to be in ready to test the inverter coolant pump. With your foot OFF the brake, press the start button to put it in ACC mode. Press it again to put the car in IG-ON mode. The inverter water pump should run when in IG-ON.

    And on another note, it sounds like you're on a path to give away a bunch of cash easter egging the problem. If you aren't confident your mechanic is familiar enough with a Prius, then find one who is. Just the first part about reading codes should have been enough to realize that shop has NO experience with a Prius. Unless of course, he works on your car for free.
     
    #17 TMR-JWAP, Jun 11, 2018
    Last edited: Jun 11, 2018
  18. Patrick Wong

    Patrick Wong DIY Enthusiast

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    Somewhat far off, because those three codes point to a problem with the position sensor (within the transaxle), or the wiring harness between the hybrid vehicle ECU and the transaxle, or the ECU itself. I suggest you subscribe to techinfo.toyota.com so that you can research those three codes and the troubleshooting tree which allows you to test the wiring harness and the position sensor. If both are good then the ECU would be replaced.

    If the ECU is replaced, then it has to be registered with the transponder key ECU so the car will start. That process is also documented in techinfo.
     
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  19. ChapmanF

    ChapmanF Senior Member

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    For those moments when reasoning like that may sound persuasive to you, don't forget that the whole protocol where the ECU recognizes your scan tool on the CAN bus, recognizes code inquiries over the connection and sends the requested information back in correct error-free format, is a pretty sophisticated bunch of steps to be getting carried out with absolute correctness by this ECU that is supposedly doing all of that to give you codes it can't correctly report.

    Also worth keeping in mind that one of those codes, a report from the skid ECU with "low battery positive voltage" in its fortune cookie, is a report from a voltage sensor built into the skid ECU and pertaining to the voltage it measures at a specific skid ECU terminal. That's at least as likely to have to do with wiring junctions, fuse connections, etc., on the wiring path to that ECU, as it is to be some comment on the battery itself.

    Patrick beat me to pointing out that some of the codes were about the position resolvers in the transaxle. If nobody has been disassembling the transaxle recently, most likely those are going to turn out to involve the external wiring connections to the transaxle.

    -Chap