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Lot of weird things with 07 Prius

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by Beowulf9879, Oct 5, 2023.

  1. Beowulf9879

    Beowulf9879 Junior Member

    Joined:
    Jun 16, 2021
    23
    2
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    Location:
    Omaha, NE
    Vehicle:
    2007 Prius
    Model:
    N/A
    Buckle up, drivers! I got a strange one for y'all.

    Every now and then, seemingly randomly, but happening with greater frequency, my '07 Prius (167000 miles, after-market hybrid battery installed) will show an orange "!" with a circle around it and a couple curved lines around that, along with the red triangle (see pic, the tire pressure light is a separate, known issue). When this happens, the only thing of note is that my cruise control stops working. The car is still functional and seemingly normal.

    IMG_20231005_141639122_HDR.jpg

    If I let the vehicle run for a few seconds, turn it off, and turn it back on again, the orange light goes away, and the red triangle stays for a time (if I can turn on the car without the orange light happening, the red triangle goes away on its own after like 3 or 4 restarts). With that orange light off, my cruise control works again. And, once again, the vehicle is seemingly functionally normal.

    In addition, if I mess with the AC (turning it on or off), the orange light activates immediately (as does the red triangle if it had disappeared by this point). Turning off the car and back on will usually make the orange light turn off, as before.

    Obviously I've had the codes pulled. I had the codes reset, waited for the red triangle/etc, and then had them read:
    1. HV ECU - P0A08 DC/DC Converter Status Circuit
    2. Cruise Control - P0A08 DC/DC Converter Status Circuit
    3. Antilock Brakes - C1310 Fault in HV System / Fault in ACTV Brake Booster Solenoid
    4. Heating & Air Conditioning - B1421 Solar Sensor Circuit (Passenger Side)
    What do you all think is the problem? Presumably it's one thing that ties everything together.

    This was on my scan report as well, and I don't know if it has anything to do with anything:

    Readiness Monitors
    Complete
    Misfire
    Fuel System
    Comprehensive Component
    Catalyst​

    Not Complete
    Evaporative system
    Oxygen Sensor​
     
    #1 Beowulf9879, Oct 5, 2023
  2. mr_guy_mann

    mr_guy_mann Senior Member

    Joined:
    Sep 3, 2020
    3,444
    1,496
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    Location:
    NJ-USA
    Vehicle:
    2006 Prius
    Model:
    Four
    So, the B1421 A/C code sets anytime you don't have the car parked in strong sunlight - ignore this.

    The C1310 sets when there's a fault in the hybrid system (Hybrid Control - HV ecu or the HV battery ecu).

    The P0A08 sets when the HC ecu doesn't like "something" about the DC-DC converter in the inverter assembly. Cruise Control isn't a separate ecu, it's part of the HC ecu function.

    First would be to check the connections at the 12V battery - are they clean and tight - also the body end of the negative cable.

    Now check the small wire and 5A fuse at the connection block on the 12V battery positive connection. This goes to the HC ecu and loose terminals or wires will cause problems.

    Check coolant level and circulation in the inverter coolant reservoir (the pump should run if power is "ignition on" or at "ready").

    Beyond that you will need to follow diagnostic procedures in the service manual.

    Posted via the PriusChat mobile app.
     
    #2 mr_guy_mann, Oct 6, 2023
    Beowulf9879 and Brian1954 like this.
  3. Beowulf9879

    Beowulf9879 Junior Member

    Joined:
    Jun 16, 2021
    23
    2
    0
    Location:
    Omaha, NE
    Vehicle:
    2007 Prius
    Model:
    N/A
    Thank you. I will check those out and hope it stays as a non-serious issue until the problem is resolved.
     
    #3 Beowulf9879, Oct 7, 2023
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