Check engine light, P0101 and P0172 codes. Safe to drive?

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by srellim234, Jul 13, 2022.

  1. srellim234

    srellim234 Senior Member

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    The check engine light came on and Torque Pro is showing codes of PO101 (Mass or Volume Air Flow Circuit Range) and PO172 (System too rich). Is the car okay to drive to the tire shop (picked up a nail in the left rear) and then the 50 miles to the dealer to get it fixed or should it be towed?

    Don't know if it's a contributing factor to whatever the codes are referencing but the weather has been over 110*F out here all month.
     
    #1 srellim234, Jul 13, 2022
  2. JC91006

    JC91006 Senior Member

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    Yes the car is safe to drive.

    The MAF sensor maybe dirty (or need replacement). They don't fail often so check your air filter, see if it's dirty and needs replacement also (since you have to remove filter to see the MAF sensor)

    There is a MAF sensor cleaner you can buy for less than $10, just spray it on there (after you take it off the car). If cleaning it doesn't get rid of the check engine light, then go buy another used part from Ebay or something (original part would be best). You may be able to get them at junk yards too (since Gen 2 cars are becoming disposable)
     
    #2 JC91006, Jul 13, 2022
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  3. JC91006

    JC91006 Senior Member

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    #3 JC91006, Jul 13, 2022
  4. PriusCamper

    PriusCamper Senior Member

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    Don't take the car to the dealer... It's way too old for that. Toyota dealers are warranty specialists. They're 100% guaranteed to try to replace the most expensive parts even if it's not necessary because that's how they get the most benefits for their business when they do warranty work. You need to find an honest mechanic who will fix your problem for lowest cost, not the highest.
     
    #4 PriusCamper, Jul 13, 2022
  5. srellim234

    srellim234 Senior Member

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    Thanks for the advice. The air filter is relatively new but out here with the dust storms ia new one can get dirty in a hurry. I'll try your tips and see if that works. If not, I do have a local mechanic who has done a few things but has very little experience with Gen II Prii.
     
    #5 srellim234, Jul 13, 2022
  6. srellim234

    srellim234 Senior Member

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    BTW, Long time no talk. was your business able to survive the slowdown from the pandemic? How's your wife these days?
     
    #6 srellim234, Jul 13, 2022
    Last edited by a moderator: Jul 14, 2022
  7. SFO

    SFO Senior Member

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    Is this the same issue, or did it come back again : PO101 and PO172- Okay to drive one hour to dealer? | PriusChat

    In case someone else finds this thread and needs the 2004 (dated) workups for those codes (DTCs) :

    Here is the workup for DTC P0101 : https://share.qclt.com/%E4%B8%B0%E7%94%B0%E6%99%AE%E7%91%9E%E6%96%AF%E5%8E%9F%E5%8E%82%E8%8B%B1%E6%96%87%E6%89%8B%E5%86%8Cpdf%E6%A0%BC%E5%BC%8F/Repair%20Manual/04pruisr/05/2054m/cip0101.pdf

    Here is the workup for DTC P0172 (and P0171) : https://share.qclt.com/%E4%B8%B0%E7%94%B0%E6%99%AE%E7%91%9E%E6%96%AF%E5%8E%9F%E5%8E%82%E8%8B%B1%E6%96%87%E6%89%8B%E5%86%8Cpdf%E6%A0%BC%E5%BC%8F/Repair%20Manual/04pruisr/05/2054m/cip0171.pdf
     
    #7 SFO, Jul 13, 2022
  8. srellim234

    srellim234 Senior Member

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    It's back again, six months after the dealer fixed it and cleaned the throttle body.
     
    #8 srellim234, Jul 14, 2022
  9. SFO

    SFO Senior Member

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    What did the dealer do last time; just cleaned up the MAF, throttle body, and butterfly valve?

    Was there anything else listed on the invoice?
     
    #9 SFO, Jul 14, 2022
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  10. mr_guy_mann

    mr_guy_mann Senior Member

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    If you had the problem happen again, did the dealer ever really "fix it" in the first place?

    What do you have to scan the car, and are you interested or capable of diagnosing this yourself?

    Posted via the PriusChat mobile app.
     
    #10 mr_guy_mann, Jul 15, 2022
  11. srellim234

    srellim234 Senior Member

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    They couldn't find the specific problem in January so they did exactly that.

    I decided to take it there yesterday anyway. A quick clean of the MAF didn't help. Tests showed the long term trim (whatever that is, I'm not a mechanic) at 30%. They swapped in a used MAF from another car and everything checked out fine, meaning the original MAF wasn't getting something bad fed into it; the problem was the MAF itself. They installed a new MAF. According to the invoice, "Replaced sensor, cleared codes and retested. Long term fuel trim now at 10% and all input and output readings are normal."

    I know it was expensive going through the dealer but I'm not a DIY guy and there aren't any mechanics around here that are comfortable working on a Prius. Even a medical courier service was using Prii and running their cars down to the dealer in Lake Havasu. The courier finally changed vehicles since there are mechanics, a Ford and a Buick/Chevy/GM dealer here locally for ICE cars. This area has a lot of catching up to do with regards to hybrids and electrics.
     
    #11 srellim234, Jul 16, 2022
  12. dolj

    dolj Senior Member

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    The funny thing is that that part of the engine is no different from a Corolla, Yaris, or Camry. In fact, probably not a lot different from a myriad of mainstream cars.
     
    #12 dolj, Jul 16, 2022
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  13. DigDoug

    DigDoug Junior Member

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    I have the same recurring problem, happened around a month ago was replaced with a new air filter and now I have it again.
     
    #13 DigDoug, Jul 19, 2022
  14. mr_guy_mann

    mr_guy_mann Senior Member

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    What codes do you have? Did you do anything besides replacing the air filter? Have you tried properly cleaning the MAF sensor and throttle body?

    Posted via the PriusChat mobile app.
     
    #14 mr_guy_mann, Jul 19, 2022
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  15. DigDoug

    DigDoug Junior Member

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    I replaced the MAF and air filter. PO101 is the only code I am getting. This was the first code since the replacement battery. I kept the original MAF and may just purchase some cleaner, clean and reinstall it.
     
    #15 DigDoug, Jul 20, 2022
  16. DigDoug

    DigDoug Junior Member

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    Things just get curiouser and curiouser, had the CEL light on when I went to work today and again when I returned home, just about a half an hour ago I moved the car and no code. I am flummoxed here.
     
    #16 DigDoug, Jul 20, 2022
  17. JC91006

    JC91006 Senior Member

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    A bad catalytic converter would do that
     
    #17 JC91006, Jul 20, 2022
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