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Can debris in the mass airflow sensor shut the car down?

Discussion in 'Gen II Prius Technical Discussion' started by avictoria, Jun 22, 2010.

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  1. avictoria

    avictoria New Member

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    I've owned my 2007 Prius (45,000 miles) for 5 days. Friday, it just shut down while on the freeway. After having it towed to the dealership, they diagnosed the problem as the mass airflow sensor being full of debris and needing to be cleaned. Can this really cause the car to simply stop running? If so, how can I prevent this from happening again?
  2. MJFrog

    MJFrog Active Member

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    Two main items to check on:
    1. Don't overfill the oil when it gets changed (3 qts is plenty on a gen II). Verify the level is BETWEEN the two spots on the dipstick. Not too low, not too high
    2. Replace your engine air filter
    1 person likes this.
  3. richard schumacher

    richard schumacher shortbus driver

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    What kind of debris?

    If the engine air filter is intact, if it is installed correctly and there is no damage to the housing, then there is no way for debris to reach the MAF sensor. (However it can get oily if the engine oil is overfilled for a long time...) It is easy to install the engine air filter upside down, in which position it will not catch everything, so maybe the former owner or some Kwiky Loob doofus is to blame.

    Did you buy this car from that dealer? If so it makes me wonder what else they didn't inspect before selling it to you. It would be prudent to return it to them and insist on a complete inspection for free. If they resist take it to a different dealer to inspect it and don't ever go back to the first one. If you bought it privately consider this episode a reminder that *every* used car should be thoroughly inspected before buying, and then take it to a dealer for inspection. So many things can be wrong on a modern car it'll make you ill.

    If the correct year Owner's Manual did not come with the car buy one from a dealer. It's full of stuff you need to know. If you don't have the Scheduled Maintenance Guide see here:
    http://smg.toyotapartsandservice.com/
    1 person likes this.
  4. Bob64

    Bob64 Sapphire of the Blue Sky

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    exactly what do you mean by shutting down?

    Loss of engine power? Suddenly everything turning off? Lots of warning lights?
  5. avictoria

    avictoria New Member

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    Lots of warning lights - warning sign, battery, tire pressure...
    I think it lost engine power. All the warning lights came on, and it felt like the engine died. It let me drive approx 20mph for an additional 2 minutes before it completely stopped running. I was still able to power the car on, put it in gear, listen to the radio...it just would not do anything when I pressed the gas.
  6. hobbit

    hobbit Senior Member

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    The MAF absolutely can take out the engine. I stopped to help
    a lady on the side of the road a couple of years ago and as much
    as I poked stuff with a voltmeter and eyes/ears/etc I couldn't
    get her going; like an idiot I didn't think to pull the air filter
    and look down the throat and it turned out later that some small
    bits of leaf debris had lodged in her MAF and that's what did it.
    The thing is *very* sensitive; even waving a finger over the
    general area of the opening can radically change how the engine
    runs when idling, so I've gotten paranoid about the thing.
    I detail easy inspection/cleaning in my 100K maint page.
    .
    _H*
    2 people like this.
  7. vertex

    vertex Active Member

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    1 person likes this.
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