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just bought first Prius as a fixer and need help

Discussion in 'Gen 2 Prius Main Forum' started by mobilefleet, Sep 30, 2014.

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  1. mobilefleet

    mobilefleet New Member

    Joined:
    Sep 30, 2014
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    Vehicle:
    2005 Prius
    Model:
    ----USA----
    well, it's alive!! $350 for new key/programming/clear hybrid codes. It runs well but has a few lights staying on the dash and the a/c does not seem to cool very well. The lights are: red triangle with exclamation, VSC, check engine, and a round orange light with an exclamation. I scanned the OBD port and it has a P0031 which appears to be an air/fuel mixture sensor but not sure where it would be located on the car. Fuel was nearly empty and it may have been months or even a couple years sincde it has been run/driven so I will not condemn the lights just yet, could just need a good driving down the road to reset everything to good parameters. Any advice on these lights or a/c? I assume I can check the a/c like a regular R134 port with gauges? can you refill it with same procedure as other cars? I know it has an electric compressor and not belt driven
     
    #21 mobilefleet, Oct 18, 2014
  2. valde3

    valde3 Senior Member

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    Location:
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    Vehicle:
    2004 Prius
    Just disconnecting 12V battery for some time should clear codes. If it still shows warning lights then you should really use mini-vci and techstream or some other hybrid compatible scanner. AC uses normal R-134 coolant but different oil (and oils aren’t mixable) so you should only use gauges that aren’t used with regular ac-systems.

    P0031 is OXYGEN (A/F) SENSOR HEATER CONTROL CIRCUIT LOW (BANK 1 SENSOR 1). So it means that air-fuel sensor (better version of oxygen sensor) (closest one to engine) heater isn’t using enough current. Sensor isn’t cheap so maybe you should check other stuff before replacing that and it will only make our check engine light on.
     
    #22 valde3, Oct 18, 2014
    Last edited: Oct 18, 2014
  3. derekderek

    derekderek Junior Member

    Joined:
    Oct 11, 2014
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    Location:
    westville NJ
    Vehicle:
    2004 Prius
    Model:
    II
    the heater circuit code usually is a bad sensor. heater burned out, passes no current. it could also be unplugged...
     
    #23 derekderek, Oct 18, 2014
  4. nh7o

    nh7o Off grid since 1980

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    Location:
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    Vehicle:
    2009 Prius
    Model:
    II
    What did you use to do the scan? I would recommend getting the mini VCI, or some other Prius oriented alternative, and be certain of the info. There are many stories of generic scanners not working with the Prius. The VSC, triangle, etc. lights indicate there are other DTC set, which your scanner is not seeing. Also, generic scanners give false readings, so get another scan before doing any work on the P0031.
     
    #24 nh7o, Oct 19, 2014
    Britprius likes this.
  5. Britprius

    Britprius Senior Member

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    Location:
    Herefordshire England
    Vehicle:
    2008 Prius
    I could not agree more with "nh70's" comment above. If you intend doing any diagnostic work on the Prius or even your own service work in the future the Mini VCI is a must have piece of equipment. I have the ability to run Priidash, Torque, and the VCI with Techstream . While Priidash and Torque are excellent for monitoring they do not come close for actual service work and diagnostics to the ability of the VCI. Conversely the VCI and Techtream is not as versatile at providing extra instrumentation or dashboard information as the other two.

    John (Britprius)
     
    #25 Britprius, Oct 19, 2014
    PriusGuy32 likes this.
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