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Knock Sensor p0327, p0328 Check Engine Light

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by yurtdweller, Jan 30, 2017.

  1. yurtdweller

    yurtdweller New Member

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    Howdy folks.

    My Check engine light came on the other day. Engine ran poorly when climbing a hill. Sort of surging. (may be a red herring)
    Trouble code p0327 (Knock Sensor 1 Circuit Low Input) came upon scanning.
    I replaced the knock sensor, and now I get p0327 and p0328 (Knock Sensor 1 Circuit High Input)

    Any help in clearing this up is appreciated.
    Can I drive it without damaging anything?
    Thanks in advance.
     
  2. andrewclaus

    andrewclaus Active Member

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    What scanner did you use to read the codes?
     
  3. MAGARIVAR

    MAGARIVAR New Member

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    I've got 2 codes. one is 3000H/12288
    the other one is P3009

    does anyone know about these codes and how do I post a question? I just signed up but do not see where I should post a new question, thank you for explaining n detail how I should do that...

    when trying to isolate the problem it only comes up when the engine is ON / ready and in Neutral Gear but does not come up if I just start the ignition (before cracking the engine, no codes)... so what seams to be the problem?
     
    #3 MAGARIVAR, Jan 30, 2017
    Last edited: Jan 30, 2017
  4. yurtdweller

    yurtdweller New Member

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    #4 yurtdweller, Jan 30, 2017
    Last edited: Jan 30, 2017
  5. edthefox5

    edthefox5 Senior Member

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    That will read obd codes but not hybrid codes.

    If knock sensor engaged it means it's sensing a knock. We are seeing a lot of Prius lately with engine damage caused by high mileage poorly maintained oil levels. Many high mileage Prius eat oil and owners allowed to let oil go so low it damages main bearing or
    piston bearing.
    Engine bottom end is splashed lubricated. Low oil level no splash.
    If yellow engine light lit because of low oil I can almost guarantee you it has
    Been damaged.
    When knock sensor engaged it pulls engine timing and engine will have no power.
    Go on you tube look up Prius inspection mode
    That puts the car in continuous engine run. With engine on get under front of car and listen to engine for knocking or vibration.
     
  6. MAGARIVAR

    MAGARIVAR New Member

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    you can only if you wear eye protection and stay away from alcohol :) but kidding aside, its a good idea to invest in a toyota specific scan tool. some are expensive some not at all. I've seen a cable with a CD as low as $17 but you do need a laptop preferably with XP on it. That's what the pro's recommend. Then you can get an accurate reading of codes that relate to hybrid system. Good luck!
     
  7. yurtdweller

    yurtdweller New Member

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    If this is the case, a motor swap is in the future, correct?
     
  8. andrewclaus

    andrewclaus Active Member

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    That's probably correct, but is this the case? Is your engine high mileage, with some oil-burning issues, and perhaps not perfectly maintained?

    If you've been diligent about maintenance, maybe you do have a more complicated emissions or engine control issue, and a Mini-VCI and laptop will help diagnose it correctly.
     
  9. MAGARIVAR

    MAGARIVAR New Member

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    keep the motor change the body..
     
  10. yurtdweller

    yurtdweller New Member

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    Here's an observation :
    When I erase the code, the check engine light returns immediately. Less than 1 second.
    I feel like if there was a problem with knock, it would at least wait to run diagnostic.
     
  11. Samprocat

    Samprocat Active Member

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    Why have you change knok sensor...did you inspect ignition ..spark plug ...fuel delivery..injectors...timing marks before you have engaged to replace knok sensor
    Another reason could be fuel quality...that will trigger knok sensor....
    Don't just start changing things till you are definitely sure you have sensor issue....eliminate all causes that will trigger knok sensor first
     
  12. yurtdweller

    yurtdweller New Member

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    I checked the web for answers on how to proceed. This was what I found:

    Common Causes of P0327
    To sum things up, the common causes for code P0327 are as follows:

    • Failed knock sensor
    • Fault in the knock sensor circuit
    • Failed PCM

    Before I swapped out the sensor, I got just one code p0327. After changing the sensor, I get two codes. p0327 (low input voltage) and p0328 (high input voltage). I am thinking that the new sensor is defective.

    When I erase the code, the CEL light comes back on immediately. (within one second). I believe that is telling me that there is a problem with the sensor, not a knock, as there does not seem to be enough time to perform a test, and because the light will return even while the gas motor is not running.
     
  13. andrewclaus

    andrewclaus Active Member

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    I think your reasoning is okay. If the knock sensor is working and senses knocks, it doesn't give a code, it attempts to correct the knock with ignition timing, etc. I think the code is just to supervise the circuit, as you've deduced.

    Is it hard replacing the sensor? It looks like it's under the intake manifold. Did you get an OEM sensor?
     
  14. yurtdweller

    yurtdweller New Member

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    Thank you for the reply, Andrew. No need to panic when a sensor circuit fails.

    To get to the sensor, move the air box out of the way. 2 10mm bolts up top, one 10mm bolthead hose clamp underneath.
    The sensor is behind the intake. 12 mm bolt with tight quarters. I removed a bolt on the intake manifold to allow I little more space. I also had to bend a 12mm box Wrench to get any travel on the Wrench. Once broken free, I was able to get one finger tip on the nut and spin it tiny bits at a time. When it was backed out a bit, I could get a socket and wobbly on there, just not fully engaged.
    Very scared to lose the nut.
    I found I could reach up from below with my left arm under the intake. Not a procedure for the claustrophobic.
     
    Paul Schenck likes this.
  15. 05PreeUs

    05PreeUs Senior Member

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    This is an example of why I HATE code readers and the technicians that use them to fix everything... :mad:

    P0327 is a CIRCUIT code, essentially the input VOLTAGE is LOW

    P0328 is also a CIRCUIT code, essentially the input VOLTAGE is HIGH

    Engine knock codes are: P0301, 2, 3, 4, last digit is the cylinder number

    Additionally, if you are getting pre-ignition/engine knock/misfires the check engine lamp should be FLASHING
     
  16. yurtdweller

    yurtdweller New Member

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    Replaced knock sensor with cheapo ebay, CEL persisted. Replaced el cheapo with Denso and walla! CEL is gone.
     
    Aaron Vitolins likes this.
  17. CrazyLee

    CrazyLee Member

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    I don't think Toyota engineers are that dumb to put splash lube on one of the most sophisticated cars that they designed. That's why there is a lower mark on the dip stick and a higher one. Keep within those marks you are good.
     
    Paul Schenck likes this.
  18. Paul Schenck

    Paul Schenck Active Member

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    I better wait and put a fresh tank of detergent gas in before I replace it I suppose


    iPhone ?
     
    #18 Paul Schenck, Oct 2, 2019
    Last edited: Oct 2, 2019