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Idle control system?

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by Athena, Aug 7, 2014.

  1. Athena

    Athena Junior Member

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    Hi everyone. Just got a diagnostic from the nice people at Prius Battery Repair of Houston. Check engine light was on and intermittent red triangle when I make a left turn. Code PO505 came up- Idle control System. Any words of wisdom? Anyone know a good Prius mechanic in Houston? I have been using the dealership but would like someone honest and more economical. I have 162,000 miles and just put in a reconditioned battery that checks out fine. Thanks
     
    #1 Athena, Aug 7, 2014
  2. Patrick Wong

    Patrick Wong DIY Enthusiast

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    DTC P0505 means that the engine idle speed substantially varies from the target established by the engine ECU. You can try cleaning the throttle body interior and throttle plate. Check for a leak in the PCV hoses and the air induction system downstream from the throttle plate.

    If that doesn't help then the throttle body (which includes the throttle motor) will need to be replaced. If you can find an independent, you can ask for a used part to be installed to save you some $$$.
     
    #2 Patrick Wong, Aug 7, 2014
  3. RobertK

    RobertK Member

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    When did you last check your engine oil level? Low oil levels have been reported as the reason for the red triangle appearing when cornering. This won't throw a code, but is easy to check and correct. You may have more than one problem.
     
    #3 RobertK, Aug 7, 2014
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  4. Athena

    Athena Junior Member

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    thanks everyone! I cleaned the MAF and the throttle body- changed the oil. Should the check engine light go out automatically if this solved the problem(s) or does it have to be reset somehow?
    Thanks for helping an old white haired lady!
     
    #4 Athena, Aug 9, 2014
  5. Patrick Wong

    Patrick Wong DIY Enthusiast

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    The engine ECU should reset the check engine light if the underlying problem is gone, after 2-3 engine starts. You can also force a reset by disconnecting the 12V battery for a few minutes, for example by removing the negative battery cable where it bolts to the body.
     
    #5 Patrick Wong, Aug 9, 2014
  6. Athena

    Athena Junior Member

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    Thank you! Hopefully the problem was solved with the cleaning and I won't need to replace the throttle body!
     
    #6 Athena, Aug 9, 2014
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