2008 Prius - P0A72 and C1310

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by Todd Wallace, May 9, 2023.

  1. Todd Wallace

    Todd Wallace Junior Member

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    Hello folks - I'm helping some friends with their 2008 Prius. They left a door open overnight and drained the 12v battery. It was completely dead in the morning. They jumped off the dead battery with a running RAV4 with jumper cables. On restart with a charged 12v battery error lights popped up and green car symbol changed to limp mode. Red triangle, brake with exclamation, VSC, and check engine lights on. Engine won't start. Put OBD2 scanner on and got P0A72 and C1310 codes. I checked all the fuses - all good. I swapped all the relays in the fuse box - no change. I disconnected the 12v battery to reset and the car started and all looked normal - the 12v battery was charging correctly and the hybrid battery was charging correctly with no warning lights. I shut the car off and restarted it. Warning lights now back on with P0A72 and C1310 coming up again and car in limp mode. Does this sound familiar to anyone? I don't have access to sub codes at this time, just hoping someone has been through this and can point me to the fix. Thanks for any responses....
     
    #1 Todd Wallace, May 9, 2023
  2. ColoradoCrow

    ColoradoCrow Senior Member

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    Disconnecting the 12V battery can reset the codes....However It takes the car a long, long time to recharge the 12volt battery it is NOT like a regular ICE car. Like let it idle for 4 hours IIRC. Do you have a slow trickle smart charger? I would get one and hook up to that overnight. Also if the 12v battery is more than 4 years old it might not recover. Have it tested at the auto parts store. Maybe they can provide a slow charging service for you. If the battery is toast. it's about $200 to replace. But then your good for quite awhile.
     
    #2 ColoradoCrow, May 9, 2023
  3. Todd Wallace

    Todd Wallace Junior Member

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    I had replaced the dead battery with a fresh 12v battery first thing. .
     
    #3 Todd Wallace, May 9, 2023
  4. ChapmanF

    ChapmanF Senior Member

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    The C1310 code is just there because of the P0A72. In the repair manual, the troubleshooting steps for P0A72 will be the important ones.
     
    #4 ChapmanF, May 9, 2023
    ColoradoCrow and Todd Wallace like this.
  5. Todd Wallace

    Todd Wallace Junior Member

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    All the sub codes for P0A72 point to there being a fault in the Inverter or wire harness. Before replacing the inverter, is there another possible solution that anyone has figured out for the P0A72 code? Again, this is related to an electrical short when jumping a completely dead 12v battery with jumper cables from a running car.
     
    #5 Todd Wallace, May 10, 2023
  6. ChapmanF

    ChapmanF Senior Member

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    When there's a choice like that, the rest of the troubleshooting steps will have you figure out which it is, so then you fix that.
     
    #6 ChapmanF, May 10, 2023
  7. Todd Wallace

    Todd Wallace Junior Member

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    I have familiarity with the Prius - sometimes the trouble codes lead you to a "rabbit hole". The P0A72 not being a common problem ... just looking for successful alternatives that others may have found...
     
    #7 Todd Wallace, May 10, 2023
  8. ChapmanF

    ChapmanF Senior Member

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    Naturally, the more common issues are the ones it's most likely there'll be crowdsourced solutions to. For the less common ones, sometimes there's not much more to go on than learning what conditions cause that code to be set (the "detection condition" shown in the manual), then finding out what caused those conditions in this car at this time.

    One certainly does sometimes see people with a trouble code be led into a rabbit hole ... by not approaching it that way.
     
    #8 ChapmanF, May 11, 2023
  9. Todd Wallace

    Todd Wallace Junior Member

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    UPDATE: We did more testing - swapped out all relays - no luck. My friends had plans and went ahead and vacationed at the shore for a week. When they returned and started the Prius, all error codes disappeared and have been driving the car with no troubles ... go figure. :)
     
    #9 Todd Wallace, Jun 15, 2023
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