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resetting the diagnostic codes

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by Katrina O, Jul 19, 2017.

  1. Katrina O

    Katrina O Junior Member

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    I recently have had my check engine light going on & off. When I last went to get it checked out they didn't do a reset (I don't believe). They weren't sure of the cause (basically throwing darts at it) and it's come on & off again twice since. I would like to clear the codes since I want to go to a different shop & get another reading. What fuse do I need to pull (I've checked the owner's manual, it isn't clear) or what is another easy way to do it?

    2008 Touring model, 102K miles.

    Thanks all!
     
  2. JC91006

    JC91006 Senior Member

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    You should get the codes read, don't erase them.

    My guess would be in this order.

    A bad 3 way coolant valve code P1121, bad gas cap, or a bad catalytic converter
     
  3. Katrina O

    Katrina O Junior Member

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    OK thanks. I do have a record of the codes that were read by the shop I went to. Yes that P1121 was one of them ( they thought it was due to low coolant level, which was the case apparently - claim they could feel coolant flowing but couldn't determine if all 3 valve chambers were functioning properly. My BF, who used to work as a mechanic some time ago, says it's BS that you can't feel coolant flowing like that but he's used to the old days hasn't worked on more recent model cars so idk.) They also replaced the water pump since it was "seeping" (it was replaced 4 yrs ago by previous owner I know they're well known for going out but is this normal wear?) Hoping not the catalytic converter. Going to be taking to a shop that knows Prii better.
     
  4. JC91006

    JC91006 Senior Member

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    They should have replaced the 3 way valve, at the same time as the water pump replacement. It's all coolant related

    Now you have to change the valve and fill coolant again
     
  5. Katrina O

    Katrina O Junior Member

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    Yeah that's really unfortunate. I only just started going to this shop ... they have a great reputation, they may be fine for a standard car but clearly know very little about Prii so I won't be returning. Interesting that they should have automatically replaced the valve when they did the water pump. Not sure it's worth my taking this issue up with them, chalk it up to live & learn I suppose.

    Is only getting 4yrs use out of a water pump normal for Gen II? Also they didn't drain & fill coolant they just topped it off. Mistake?
     
  6. JC91006

    JC91006 Senior Member

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    The check engine light is because of a bad 3 way valve. The repair should have addressed that issue. Then as a secondary issue, they discovered a leaking water pump. So that would be something they fixed, along with the primary problem, the 3 way valve. The coolant should be replaced at 100k miles, so they should have replaced it during the service

    So basically they didn't address the primary issue
     
    #6 JC91006, Jul 20, 2017
    Last edited: Jul 20, 2017
  7. Katrina O

    Katrina O Junior Member

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    Yup, they're clearly pretty clueless. This error code (& problem with valve) must be pretty common for you to have guessed it without my describing symptoms (other than light going on & off), unless you saw thread concerning my related post several days ago
     
  8. JC91006

    JC91006 Senior Member

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    It's just a guess on a fairly common issue, also catalytic converter but your car is too new and miles a bit low for that
     
  9. Paul Schenck

    Paul Schenck Active Member

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    You can use a code reader to do it they are about $50 or just disconnect the 12 volt battery with a 10 mm socket through the plastic cover left side rear hatch. There is also a way to do it on u tube pressing odometer button while turning on the car....etc.


    iPhone ?
     
  10. Paul Schenck

    Paul Schenck Active Member

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    Question? Why waste a mechanics time when you can get a code reader on line for $10.00 ??


    iPhone ?
     
  11. Katrina O

    Katrina O Junior Member

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    Sure enough. Yesterday took it to a different shop (new one for me), I knew I was in good hands when I drove up & their parking lot was full of Prii including several taxis. I described the symptoms - check engine light on/off and the noise, told him the diagnostic code and he said ok, we'll replace that valve for you. $315 before tax, I've seen folks say it cost them more so I guess it could be worse. No more mystery noise. And I've found a good shop (just wish they were more convenient, 30 min drive from me & can't get there via transportation to/from work, at least they're open on Saturdays)
     
  12. Katrina O

    Katrina O Junior Member

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    Sure enough @JC91006 . Found a good Prius place. Ended up going to Saggu Automotive Repair last Saturday. Knew I was in good hands when I drove up & saw more than half the cars there were Prii, with several taxis. When I described the CEL & the noise, the mechanic checking me in said almost 100% certain both caused by the 3-way valve. 2.5 hours (and $341, including our crazy 10% tax) later, done. I think I may even return for oil changes since they really seem to know their stuff.
     
  13. Uberjoy

    Uberjoy New Member

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    Because every shop tells me that self readings and auto zone readings aren't legit. They end up doing the test and it's exactly what free tester said. It's no way around them. It always happens to me; firestone, Toyota, meineke