In this video we see a perfect example of how a DVOM would have lead you astray when testing a piezo knock sensor. Resistance is good, AC voltage average is good but the sensor is bad!? Let the scope show you the answer so you don't go down the path of unnecessary ECM replacement!? Of course in this case if the only scope you used was the scope on the parts cannon you would have been right just winging a part at it based on the code alone but remember when that does not work it gets expensive! Test DON'T GUESS! -Enjoy!
AES Wave U-Test Kit:'>
PICO 4425 Kit:'>
If an SMA Video has helped you out please consider giving using "Patreon" to help support us. The videos take real time to create and pull us away from real work that pays our bills. CLICK HERE:
--Eric O.
If you don't like Patreon feel free to use the "PayPal Me" link:
The South Main Auto Amazon Store:
AES Wave Automotive Diagnostic Tools:
Simply send and E-mail to SMAstickers including: your shipping address and e-mail address in the text, I in turn will send you a Paypal invoice for $5 each USA or $6 each international. Let me know how many you want and as soon as the Paypal invoice is paid I will ship them out ASAP! Thanks for your support of our channel!!
--Eric & Vanessa O.
Feel like sending some swag to SMA because you love the videos but don't know where to send it?
Just ship it here:
South Main Auto Repair
47 S. Main St
PO Box 471
Avoca, NY 14809
Due to factors beyond the control of South Main Auto Repair, it cannot guarantee against unauthorized modifications of this information, or improper use of this information. South Main Auto Repair assumes no liability for property damage or injury incurred as a result of any of the information contained in this video. South Main Auto Repair recommends safe practices when working with power tools, automotive lifts, lifting tools, jack stands, electrical equipment, blunt instruments, chemicals, lubricants, or any other tools or equipment seen or implied in this video. Due to factors beyond the control of South Main Auto Repair, no information contained in this video shall create any express or implied warranty or guarantee of any particular result. Any injury, damage or loss that may result from improper use of these tools, equipment, or the information contained in this video is the sole responsibility of the user and not South Main Auto Repair

50 thoughts on “Honda knock sensor testing: could you see it without a scope?”
  1. Avataaar/Circle Created with python_avatars edjeep2000 says:

    after all these years, i finally got a scope, !!

  2. Avataaar/Circle Created with python_avatars Gary R says:

    This is interesting, think I'll try it see what i come up with. Thanks for showing us what wave forms to look for, i would have never realized what was good or not.

  3. Avataaar/Circle Created with python_avatars Larry Fine says:

    The Pico is way out of my price range. Just bought a Hantek. Looking forward to putting it to the test in the future. The more I've watched your videos, the more I am convinced a scope is a necessary tool in the shop.

  4. Avataaar/Circle Created with python_avatars roger williams says:

    A really neat test old and new side by side thank you

  5. Avataaar/Circle Created with python_avatars trublue2319 says:

    Good one

  6. Avataaar/Circle Created with python_avatars Bill Smith says:

    Would the old Snap On MT-2400 Vantage test this ? If I can get one at a reasonable cost . But it is limited in what can do . Or a quality graphing multi meter ?

  7. Avataaar/Circle Created with python_avatars MrSipotek05 says:

    I had a problem with my Honda Fit 2015 I want to know where I can find out the knock sensor from the Honda 2015 if you can you be a dental in to send me answer please thank you

  8. Avataaar/Circle Created with python_avatars MacDonalds Motorworks says:

    considering where the knock sensor it on that car, would you be comfortable/confident in probing the line someplace convenient to see the waveform? Just thinking it'd be easier to do that then remove and WOULD confirm if it's an ECM problem not the knock sensor.

  9. Avataaar/Circle Created with python_avatars Ian Whatley says:


    I have just come across your video on how to test a knock sensor for the honda crv.

    My 2004 honda crv petrol (K20A4 Engine) check engine light came on I plugged my diagnostic tool in, it came up with the code P0325 knock sensor 1 circuit bank 1 or single sensor.

    I looked on youtube how to remove the knock sensor on the cvr, one way was from underneath the car by removing the front valance to gain access.

    I put my car up on ramps removed the plastic front valance, I could only just see the knock sensor. I don’t think I can get it out this way, even though some video’s say you can remove it this way. So, I just sprayed it with WD40 and left the plastic front valance off for now.

    I have deleted the fault codes and the light has not came back on yet after driving it daily.

    Do you know of any way of how to do the wave test with the knock sensor still in the car? without trying to get up under the car and struggling to undo the sensor wire to put one end of the scope (diagnostic tool) to it.

    I am hoping that you may know which way the wire is routed and if there is and wire connector I can undo to get to this wire.

    I don’t want to take off the air intake and other things yet, just to test it

    Many thank


  10. Avataaar/Circle Created with python_avatars Master Chief 00117 says:

    Any true RMS meter with a graphing display will see that.. A Fluke 189-289 would see that easy.. A good used cost $250.00-$350.00 with accessories.

  11. Avataaar/Circle Created with python_avatars Edwin Brewer says:

    Thanks for the video. Do you share your scope patterns on Pico?

  12. Avataaar/Circle Created with python_avatars Esteban Villela says:

    Honda's will set the knock sensor code after 5 seconds of no voltage change at the knock sensor when running.

  13. Avataaar/Circle Created with python_avatars P Anon says:

    Literally just having gotten a scope I am really getting a ton of valuable information from your scope vids. Thank you!!
    I'll add, I do like it when you explain exactly how and where you are making connections to test points. That gives us a good starting point when testing on our own.

  14. Avataaar/Circle Created with python_avatars kingkong8974 says:

    Wish I had a modis but shits so expensive

  15. Avataaar/Circle Created with python_avatars 426 HEMI says:

    great video as always, but dang it, I can feel the money leaving soon for a new Pico scope 🙂

  16. Avataaar/Circle Created with python_avatars Norman Gallant says:

    good presentation

  17. Avataaar/Circle Created with python_avatars Chris Katanic says:

    Great video, Eric. I had a Honda come into my shop today with a P0325. Hooked up the scope and tapped the block and the signal looked like garbage… just like the bad sensor in your video. It's nice to be able to tell the customer with certainty exactly what they need and know that it's going to fix their vehicle.

  18. Avataaar/Circle Created with python_avatars carl brandon says:

    What are the green and blue tanks in the background ?

  19. Avataaar/Circle Created with python_avatars William Bass says:

    Its expensive becoming a mechanic i just got the power probe 4 now i kinda want these scopes…. the only thing that sucks is im not making the money i need to buy everything i want lol i guess it will eventually pay off

  20. Avataaar/Circle Created with python_avatars No Name says:

    Hi, You can also use FFT mode of the scope to see frequency and power distribution (spectrum) of these two sensors. Apparently defective one adds extra harmonics to the measurement and this (harmonic distortion) can be seen better on frequency domain. Thanks for the video.

  21. Avataaar/Circle Created with python_avatars manwiththestar says:

    You can do a quick test with the multimeter, to know if it's completely dead or not. But if the multimeter says it's good then you can whip out the scope.

  22. Avataaar/Circle Created with python_avatars Rodney Farmer says:

    I never though about a pawn shop to look for a scope! That's for the info viewer

  23. Avataaar/Circle Created with python_avatars Rodney Farmer says:

    What scope did you use and about how much does it cost do you have to have the net?

  24. Avataaar/Circle Created with python_avatars marty says:

    That is soooo cool!! Yous be a genius! Damn scope again!!!

  25. Avataaar/Circle Created with python_avatars Hola! Mikey Dread says:

    thank for the info

  26. Avataaar/Circle Created with python_avatars Tom Dewey says:

    That's a good scope display Eric.. How about a "how to" vid sometime with replacement of those ever so troublesome GM 5.3L V-8 engine knock sensors? I did mine (with stupid crazy price) of the 2-wire harness as well a few months back.

  27. Avataaar/Circle Created with python_avatars Cobra Ninety Six says:

    Great video. There's nothing like having solid proof that the job is done right. Credibility leads to happy customers and more business!

  28. Avataaar/Circle Created with python_avatars Wayne BEAUDETTE says:


  29. Avataaar/Circle Created with python_avatars Jim Trainor says:

    Is "1 MS" the scope's sample rate? (1 million samples per second) It's to the right of "500 ms/div" on screen shot.

  30. Avataaar/Circle Created with python_avatars pleasecho2 says:

    OK thats Honda. But is this information transferable? Would you or have you found other ECM's to be as fussy with regard to quality of the waveform?

  31. Avataaar/Circle Created with python_avatars arcdraw says:

    I picked up a nano scope from aes wave a few years back fro about $120. It’s a single channel but it does the job quite well.

  32. Avataaar/Circle Created with python_avatars Andy Mechanic says:

    Excellent video Eric, a perfect example of why a scope is required to make a conclusive diagnosis. Great job. Cheers Andy

  33. Avataaar/Circle Created with python_avatars lolz larkin says:

    Anyone want to suggest a good scope for out in the field work. A pico and a laptop is a bit too delicate for my kind of work. Construction site heavy machinery. Don't think I can justify a fluke 123 or a snap off price tag though.

  34. Avataaar/Circle Created with python_avatars Randy Marion says:

    Thanks for this video! I recently had knock sensor codes on my 02 Toyota and, sadly, I have limited DIY tools… No scope, not that I would have known how to use it anyway. And 'Son of a Monkey to get to' is putting it mildly. When I got to it, the sub harness was trash… old with brittle connectors from years in the engine heat, and that could have well been the issue right there, but being so danged difficult to get too, there was no way I was going to not replace the sensors as well. All ways wondered how I could have actually tested the old ones and now I know! Thanks again and keep em coming!

  35. Avataaar/Circle Created with python_avatars Inge Jeppesen says:

    Did you know it was bad before you compared it to a new one?

  36. Avataaar/Circle Created with python_avatars AUTOTECH says:

    How do you keep the shop so neat? I am a one man shop and man its hard to keep shop neat. Mine is not dirty but everything in its place rarely happens.

  37. Avataaar/Circle Created with python_avatars AUTOTECH says:

    Every tool has a hammer side! LOL That's funny I don't care who you are.

  38. Avataaar/Circle Created with python_avatars D N says:

    Even as a DIY guy I have a scope and bidirectional scan tool. Why give the dealers the money when I can do most of it myself. The labor and charges saved over the years will make my money back since I keep vehicles long term.

    I do a little side work to help offset some costs but not much enough to pay for the scan tool & scope. It's a learning experience and I love doing it even as a hobby. I was sold on Scope few years back as soon as I watched a ScannerDanner video. Even broke down and bought the book. You need this stuff with today's complex vehicles.

    ~"IF you love what you do you'll never work another day in your life"~

  39. Avataaar/Circle Created with python_avatars Arthur Rodesiler says:

    Hey Eric could you please help…..jeffescortlx on YouTube get to over 1,000 so his channel can stay going. He is a true artist at repairing clusters for GM cars and trucks. He fixes what so called expert's can't or won't touch. He may do other makes am not sure. I know you know a lot of people on here and your site as well. Check his channel out and ask people you no to support his channel because it would be a shame to loose this kind of artist. Thanks Art. P.S. he only needs about 50 more to keep his channel up.

  40. Avataaar/Circle Created with python_avatars QQTrick1QQ says:

    A PRINCIPLE called “entropy” operates throughout the universe. Entropy is defined as “the ultimate state reached in the degradation of matter from the physical and chemical action of weather, and friction from use. It is the principle we sometimes complain about as our automobile wears out needing repairs.

  41. Avataaar/Circle Created with python_avatars BChrisL says:

    ASYMETRICAL WAVEFORM from the defective sensor.

  42. Avataaar/Circle Created with python_avatars CrimsonKnight says:

    Eric O Putin on a scope clinic