DIY Knock Sensor Diagnosis Honda CRV P0325

2003 Honda CRV with a P0325 Knock sensor Circuit code is diagnosed.
If you are interested in the automotive diagnostics book mentioned in the video, visit www.schrodingersboxQM.com and you can download it for only $3.49. You can learn more about the book in this video here: • Schrodinger's Box Auto...

[@nokalamaduna2709]

That term, 'right tool for the right job' goes a long way Matt, do not worry about other people. Go to any workshop that services equipment, you'll laugh the whole day just by looking at people using anything in their disposal to fix any issue. Amazing. Greatings from Benoni, South Africa.

[@SchrodingersBox]

Duly noted. But also I am trying to change people’s thinking as well so they have a better chance to improve as well!!

[@TomasLineros]

2 videos in one day!! Absolutely awesome!!!! Thanks, Matt!

[@SchrodingersBox]

Yeah I had 4 cars this weekend!! Its crazy. I remember when I started I would be luck to get 4 cars in a month. Now its up to 6 cars a weekend

[@rplayer9969]

WOW, It didn't take you no time at all to fix my sign in to your website. I can't believe how you make complicated subjects so easy to understand. I'm 73 now and your videos or should I say "School" is my number 1 hobby. Bowling is now my 2nd hobby.

[@SchrodingersBox]

hahahahaha I am glad to come before bowling lol!!

[@billyr9840]

Nice ! Matt i did the exact same car for my nephew last year. He also had a knock sensor code, but i found it was far easier to remove the intake manifold and starter to access the knock sensor. I advised him to replace the starter while i was there because it sounded tired when i pulled it in my garage. Being a cheap ass he declined. Wouldn't you know not more than a week later he got stuck with the car and had to pay a garage almost a thousand dollars to remove the intake manifold and replace the starter !

[@SchrodingersBox]

Yeah I thought I would have to remove starter to get to it but I found removing the plastic splash shields and the wiring brackets allowed me to access it just enough. Definitely some scraped up knuckles though!

[@ianj.lacoste7265]

What he teaches us is gold.

[@ytwatcher8288]

I was a tech on aerospace grade equipment, we were trained and required to measure DC voltages with a scope.

[@situationmoney]

Great info on a knock sensor!... Had a knock sensor code on a GM 3.1 engine. Ended up being a crankshaft sensor that was covered in a mixture of oil and dirt.

[@mds2465]

I just had this replaced on my ‘05 CR-V last week! I actually ended up having a mechanic friend of mine, replace it at his shop because they also wanted him to take a look at a couple of other things such as the oil pressure switch wiring connector, which snapped off on me when I was replacing the oil pressure switch due to an active engine oil leak, that’s a very common problem on these as well because it’s a very poor design. I also had a water leak that was coming into the cabin which we discovered was due to the fact that my sunroof was not closing properly so he was able to adjust that and get it to seal shut, so that there’s no more wind, noise and water leaks coming from that area. Out the door for everything. It cost me $350. Which is honestly not that bad for all that work if you think about it, I was honestly expecting it to cost me a lot more than that. He did a very good job, and I’m very satisfied with the work!

[@fredautos]

Great vid matt. Right tool, Great fix!

[@rplayer9969]

Hey again Matt, My daughter and son-in-law are coming up for Thanksgiving and I'm going to get him to sign up even if I have to pay for him. To the People that haven't made up their minds about signing up, DO IT!!! You WILL be glad you did.

[@SchrodingersBox]

Thanks for the support!!!

[@KYFHOme]

Love the channel. This is the kind of troubleshooting I love too but so often seems to escape me... A tip on using the scope from a former instrument tech, Initially using the "automatic" trigger mode like you did is great if you just want to see if anything at all is happening. But once you know roughly the amplitude of the signal of interest is, you can set the trigger to "normal mode" it will capture and retain any signal which crosses through the trigger voltage level setting. You set the trigger level to be higher than any unwanted noise but within the level of the signal of interest. In normal trigger mode the scope will trigger each time you do something which produces a signal (like each time you tap it) instead of overwriting the display automatically after each screen draw once a short time elapses with no trigger signal detected (auto mode). What you did was great and got the job done, but for teaching purposes showing the viewers the exact signal normal trigger mode might be the way to go.

[@SchrodingersBox]

Good advice. I do often use that trigger mode as well, just didn’t do it here.

[@Graham_Wideman]

I agree with your comment as it applies to general purpose scopes. However, some "lab scopes" and PC-based scopes like the Picoscope have a very long recording capacity at quite a fine time resolution (compared to most low-frequency automotive signals), so it's easy to scroll back to see any signal of interest that occurred. These don't require so much strategic setting of a trigger. Don't get me wrong -- setting a trigger is not that daunting, just it's less necessary on a scope with a long recording capability.

[@TheFuneralDirector]

Great video, i'm moving into vehicle diagnostics after spending 30 years in my last trade, i'm using picoscope automotive and your clear easy to follow videos are really useful, being new to the game i'm interested in the hacksaw method in case I get a power outage over the winter

[@SchrodingersBox]

HHahaha. If I resort to the hacksaw method we’re all in trouble. I bet you will do well on the diagnostic path. It allows for a lot longer career too- wrenching is havoc on your joints and back!!

[@NathanSmith-ut4ur]

The only real thing missing on the cheaper scopes is the waveform library for known goods. Pico only allows you access to their waveform library with “automotive” scopes. I’ve been using the Pico 2204a with very good success on diagnosing problems. Fortunately you can still use the Pico automotive software in demo mode to look at their recommended diagnostic procedures for various sensors. Not to sell anyone on a scope, but for me the price was justified in one use after it saved me hours of diagnosing. It’s essential for a home mechanic that doesn’t fire parts at stuff.

[@fredautos]

Well, that's great to hear

[@dougie2631]

But I enjoy replacing a whole car over a misfire...

[@thesmartguy3523]

​​@@dougie2631I'm sure you do the same when you run out of gas/diesel

[@dougie2631]

@thesmartguy3523 I catch that generally about the time I'm replacing the tank which happens at the bottom end of my list when firing parts

[@reneneron2971]

Hi,Matt. I had a bad NEW aftermarket knock sensor (single wire) that was causing the ECU to pull timing. This ECU would also do this if the knock sensor was disconnected. I bought an inexpensive oscilloscope and compared the waveform from the aftermarket knock sensor with what it should look like; confirmed the aftermarket knock sensor was bad. A used OEM knock sensor solved the problem. These single wire knock sensors are tuned to resonate when knock is present by the OEM so are engine and model specific; even the torque used on installing the knock sensor is critical. OEM for me on this type pf sensor and proof the value of an oscilloscope for diagnosis…even new parts can be bad.

[@SchrodingersBox]

Yes ever since Covid I have had more out of box fails than ever. I always test parts out of box now like I did with the new knock sensor.

[@randyrobison335]

Thanks for the book. I used it last night. To try a test a 3 wire crank sensor. Apparently no way to bench test it. Fun to understand how the system should work.

[@SchrodingersBox]

Oh man good for you!! The great thing about that is once you do it yourself like that, you will know it for life. Every 3 wire crank sensor you will always know how to test it and you won’t even have to look it up because you understand how it works, you don’t need to memorize wire colors or whatever.

[@rplayer9969]

Hey Matt, I'm so glad I signed up.

[@SchrodingersBox]

I am too lol!

[@DependableAutoTruck]

Knock sensor is something that i haven't had to diag. thanks for sharing

[@SchrodingersBox]

Really?? I run into maybe a couple per year. Now you can do it!! The challenging ones are when you find the knock sensor works but the code is still there. The PCM sees something other than what the sensor is producing- usually due to high resistance.

[@vehicle-stuff]

First I remember the days when you were saying things about scopes. How they are expensive and whatever. But I'm glad that you have changed your mind, not as stubborn as a lot of people. Can you propose on some cheap scopes for a DIY home mechanic? It's like with torque wrench. In a lot of cases you can go without it. But there are places that doing it without it will cost a repair pretty soon or a life. Using what you have to do a job is great by my standards. But you have to do the job correctly. That is the only result. So using what you have and do the job means that you are thinking, you know the problem, you know what your tools should do to fix it and you are not giving up, just because you do not have the factory tool. But it's wrong to use whatever on whatever. It's just not gonna happen and it will brake something (meaning it will not do the job correctly in whatever shape or form should).

[@SchrodingersBox]

Yeah I specifically remember saying at one time “I’ll never use a scope on this channel because I will never need one” hahahaha. Wow. What was I thinking?

[@BrianB-fn7pg]

"What I am supposed to do to test this use a hacksaw" 😂. Thanks for your information Matt. Keep going bro

[@SchrodingersBox]

Hahahaha. Yeah that was kinda funny. I don’t even remember saying that but I did laugh a bit in the editing when I heard it.

[@paulpaquette1961]

Nice Job Matt!!! A couple of tricks; you could use the nice little test light straight to 12v and touch the knock signal, it would read 5v because it's not programmed to read any more than that and the smoke would remain in the PCM (ask me how I know lol). A DVOM in "Diode" mode will put out a voltage, my Fluke puts out 2.5 Volts, you could inject this into the circuit as well. This would save looking for a 5V Ref which could also be hard to access. I love the fact that you are telling the DIYer's to use a scope! Take care Bud!!

[@SchrodingersBox]

Thanks. I did actually also test it using the test light method you described but didn’t include in the video because it was duplicative. But it does work as you said!

[@MrHernanliom]

LED test light to be safer right ? Just connecting to battery positive and touching the knock sensor connector and then check how it the signal on the scanner ? - btw what scope is that one ?

[@SchrodingersBox]

You could do that however it doesn’t measure voltage drop across the circuit. It would only show continuity.

[@Mr2004MCSS]

Years ago I had an intermittent CEL on my 93 S-10 with the 4.3L for a knock sensor code. Code 43. I replaced the sensor and the pigtail to the sensor and never did fix it. I traded it off soon after but that was back before I knew anything about diagnostics. I could probably figure it out these days with the knowledge and tools that I have now.

[@SchrodingersBox]

Oh for sure!! Don’t you wish you could take a stab at it today haha!!!!

[@Mr2004MCSS]

@@SchrodingersBox I do.

[@TheDisgruntledMechanic]

Great diag and nice hoodie you have there for crawling under wet dirty cars!

[@SchrodingersBox]

Hahahah I forgot to poke fun that I didn’t want to get my “good” clothes dirty lol!!!!

[@drivewasher]

Great video Matt, I personally would have brushed the bulk of the snow off outside though

[@SchrodingersBox]

With my flooring it doesn’t matter- it just runs under the tiles and outside.

[@mds2465]

I also have some seepage coming from the engine oil pan on my CR-V as well. Being that removing the oil pan would require me to lower the subframe I plan on addressing this issue when I replace the clutch.

[@mds2465]

I also noticed that the oil pan itself is dented. No idea how that happened, it was definitely before my ownership of the car. But needless to say that when I am ready to replace the clutch I will also be installing a new rear main seal, a new engine oil pan, and I'll also be replacing or possibly machining the flywheel depending on what type of clutch kit I end up installing on the vehicle.

[@Andy-ms9vi]

Since this is a DIY channel can you show how to diagnose this problem using a claw hammer and a butter knife?

[@henrybikeman]

Pro tip: To find the location of a component, look at the parts diagrams. They are worth their weight in gold. (Also helps to prevent parts misassembly errors).

[@SchrodingersBox]

Yes I do resort to that if I can’t find it within 5 minutes. Usually I can find the component in a few minutes because there are commonalities to them on all cars. A knock sensor has to be on the block somewhere. A coolant temp sensor will be on a cylinder head usually near water outlet. But yeah sometimes I resort to diagrams.

[@calholli]

I think you actually have the D7 .. The D8 costed seven hundred when I bought it. They are very similar, but the D8 has Topology and a few other bells and whistles.. it's bigger screen and has more memory too. (althought I've noticed that even the D8 has gone down in price lately).

[@SchrodingersBox]

Hahahaha dude you are correct. it is a D7!! Nice catch!!

[@burnedmyfoot]

you are awesome

[@waylonc69]

You can access from the top by removing the intake manifold. Also it's probably a broken wire to the sensor. You can bypass the plug with a jumper wire.

[@SchrodingersBox]

How can it possibly be a broken wire to the sensor? How is that possible? Also why would you remove the intake manifold as opposed to just remove the sensor with just a flex extension? 5 minutes vs 3 hours.

[@MrHernanliom]

GOOD!! What oscilloscope do you recommend ? Thanks for all your videos , I’m suscribes to the premium vids as well !

[@SchrodingersBox]

Picoscope is the best one but really pricey. I also have a used Vantage Pro that I think is great. Really just get a minimum 2 channel one and the best you can afford. You will want to upgrade it anyway at some point.

[@MrHernanliom]

@@SchrodingersBox Any min specs required for a decent picoscope ?

[@matthewr21]

"...see how it's almost like an echo..." "...the scope is the right tool..." That gives me a really crappy idea to hook it up to an amplified speaker to hear the signal... lol.

[@SchrodingersBox]

You can actually do that!!

[@joeblow6786]

1.) Boo boo juice 2.) Creamy mystery liquid 3.) Knock sensor unhappy tears

[@rrmech11]

Nice job Matt Just curious, just wondering the resistance value of each sensor. But for sure Pico for the win.

[@SchrodingersBox]

Good question. I never looked at resistance values for these. I always just looked at the signal pattern.

[@DuaneDonaldson]

You did not mention a torque value on the KNK, this is very important, do you have Service Info? Cheers.

[@calholli]

The "fading echo" that you're talking about in the signal is typically called "ringing"..

[@SchrodingersBox]

I was trying to think of a good term for it. Ringing works for me!

[@mecanicajaleite2929]

Hello, sorry for sending a question that is not related to the subject of the video. I work in Brazil and this week I came across something very different. The vehicle is a 2017 Hyundai and is equipped with a 4-cylinder gasoline engine. What surprised me is that there are two catalysts in series. And as that wasn't strange enough, the oxygen sensor responsible for determining the catalyst's useful life is installed between the catalysts. I spent a lot of time researching, but I still can't understand how ECU could monitor the efficiency of catalysts. Could you help me understand? Thank you in advance for your time and kindness.

[@SchrodingersBox]

Interesting. I have never seen that setup. I will have to look into that myself!!

[@sheerwillsurvival2064]

Oh I don’t miss working on snow covered vehicles and salt rust in my face 👊🏻👍🏻😁

[@dougkelley1266]

Do you have a 5 volt adapter for power probe or did you tap into 5 volt ref wire to test wiring and pcm

[@SchrodingersBox]

great question. I do have a 5V adapter however in this case in the video I did just tap into a 5V reference wire.

[@bernardaflores1720]

I got a D8 and a 2004 CRV. The D8 does not automatically connect to the car. I have to manually input the info.

[@SchrodingersBox]

Some cars I have been able to auto connect and others I can’t. This is a thing for all scan tools actually.

[@bmw-e30]

Can a bad knock sensor cause intermittent poor running and then correct itself. My code reader shows a knock sensor fault.

[@SchrodingersBox]

Yes it could. But so could a million other things. You will want to coordinate the knock sensor with timing adjustment to see if it’s the cause.

[@vitorangra4600]

Bom dia Montei o motor a retifica no motor do honda e agora nao apaga esta luz do sensor de batimento,ja substitui o mesmo e nada..

[@SchrodingersBox]

no comprende, it’s a riddle.

[@scientist100]

Good thing I went with computer skills then mechanical. It let me shine even without mechanical experience; I was able to diagnose in unimaginable ways that a lot of people thought I was some sort of wizard with the way I troubleshoot cars. Let the data drive you like Bernie from ATS says.

[@SchrodingersBox]

I agree. my background has been more a help with this stuff than any mechanic school would have been. no doubt.

[@scientist100]

@@SchrodingersBox I notice that you apply a strategy with possible scenarios and you map them. In my experience in Quality in the medical industry, I apply the same fundamentals that I would use during non conformance investigations which is to identify root cause and we all know that it doesn't stop at only one possible scenario and in automotive; we know that a computer coil driver didn't fry just because of luck, but rather a shorted coil so it is crucial to check coils unless they have been replaced already which is most likely since parts cannon would have given it a crack first. Thank you for keepong on sharing your knowledge.

[@SchrodingersBox]

Absolutely correct. Scientific method is the same no matter where it’s applied- whether drug development, medical diagnosis, computer troubleshooting- even plumbing. The procedure is the exact same. Science doesn’t have to be test tubes and Bunsen burners!!

[@mike-ep4wx]

Hey Matt do you have a way I can pay for the whole year thanx keep knocking it out of the park

[@SchrodingersBox]

No, sorry all subscriptions are monthly only. I do get asked this a lot though and will look into this for 2024!

[@Nothingman88]

Two in one day. You spoil us🙂.

[@SchrodingersBox]

You deserve it! Have to feed that hunger for knowledge my viewers have. Plus its fun as hell too!

[@sethdunn96]

What did you use to supply the 5 volt to the connector? Got a Corolla having a KS issue like the one in this vid.

[@SchrodingersBox]

I just borrowed from reference voltage off the TPS

[@sethdunn96]

@@SchrodingersBox Roger tht, thank you!

[@yamaha37776]

You can’t say that the water drop from the car was the 3rd most disgusting thing in your mouth and not follow up with the other 2. Haha. Also does your flooring hold up good when wet? I’m thinking about getting flooring like that. Great video!

[@SchrodingersBox]

The flooring is just simply awesome!!! It has held up virtually unscathed for 3 years now- the free flow design I got lets the water just drip right through it. I lay down right on the tile and no puddles of water or anything. It’s one of the best purchases I have ever made.

[@Lambros_Stefaneas]

​@SchrodingersBox still you didn't told us about the other 2😅

[@Lambros_Stefaneas]

😂😂😂

[@thephone7504]

The problem isn't the fact your using a scope, the problem is you didn't show how do diagnos this without a scope. Thus people saying you need a scope...

[@SchrodingersBox]

You do need a scope to diagnose this. I have other videos showing this as well. It’s the pattern, not the voltage that determines if the signal is bad or good.

[@georgecranston4351]

My subscription was at no charge does that mean I can down load your manual?

[@SchrodingersBox]

Yes you can!!

[@guilhermeg345]

Hi, I'm trying to diagnose a very high positive fuel trim problem and there's no fault codes. Could the knock sensor be the cause ? I unplugged the sensor but it's still giving knock signal readings as if it was plugged. Am I right in thinking it is the wiring to the ECU of that sensor that's causing all this mess ? It also didn't throw any code when I unplugged and turned the engine on.

[@SchrodingersBox]

Knock sensor won’t be the cause. Just stay with the extreme basics and let the data tell you where the problem is. I always start with the most basic of all- simply curve the trim against load and it will lead you in the right direction every single time.

[@guilhermeg345]

@@SchrodingersBox if it's not the knock sensor, I considered the injectors, the fuel trims don't go lower with higher rpm or with load but rather stay above 40% all the time reaching 60%. The O2 sensor seems to be working fine and reacts to blips of throttle reading rich so it's not lazy yet. I used a smoke machine and don't see any leaks also.

[@SchrodingersBox]

That won’t be a vacuum leak. That will be either a fuel delivery issue or MAF issue. I would check fuel pressure.

[@guilhermeg345]

@@SchrodingersBox Could it still be low fuel pressure even if the engine starts quick, with no excessive cranking ? Unfortunately I don't have a fuel pressure tester atm but will order one.

[@SchrodingersBox]

Yes it can. Fuel pressure isn’t really under strain at idle or cranking but under load it may be dropping. Again the fuel trim curve would demonstrate this without a gauge though- that’s why I always start with the basics first!!!

[@sanjeewaperera6950]

without correct tool to diagnose, just throw few parts at it and hope for the best.

[@georgebell3964]

👍

[@rplayer9969]

Hey Mat, I can't sign in today. It says my account has expired. I haven't had any response to my emails. Im so sad that I can't watch your videos.

[@SchrodingersBox]

Oh no I’ll check that out right away myself!!!

[@SchrodingersBox]

Ok it’s fixed. Not sure what happened there sorry about that!! Any other issues email me at Schrodinger’[e-mail].

[@ChristmasCrustacean1]

when you said the other car needed brakes, I imagined you dressed like a vampire for a halloween special where you do a parts change video. how horrifying.

[@gertryberty586]

stop ranting lol, great scope footage

[@dk4622]

Which scope for $100?

[@SchrodingersBox]

Hantek makes one. Also U-scope.

[@dk4622]

@@SchrodingersBox Saw a 2 channel Pico scope for laptop on Amazon for $165. I don't honestly need one but it would be fun to test every part. Would pay for itself.

[@SchrodingersBox]

Oh man I would totally get that!!

[@calholli]

The Owon 1022 is a great scope for 100.. also. You need a laptop though. (just like the 2000 series pico you're talking about)

[@calholli]

gadgets playlist channel

[@thekeeneygarage]

you need a snow broom

[@TheDisgruntledMechanic]

Humm! 3rd worst thing you ever had in your mouth? Ha!

[@Ironblank1]

I don’t mind spending the money on tools if they will allow me to get the job done.

[@SEXYTECH1000]

MATT, WHAT WAS THE FIRST AND SECOND MOST DISGUSTING THING YOU HAD IN YOUR MOUTH . LOL

[@SchrodingersBox]

I’m not saying hahahahaha!!!!

[@SEXYTECH1000]

@@SchrodingersBox LMAOOOOOOOOO.

[@suckOnThese3]

Uh Matt, will we in the U.S. get free subscriptions when we become a third world country in the near future?

[@SchrodingersBox]

Hahahahahaha!!!! Man I am certainly considering it. I am already considering California a third world country at this point lol.

[@mnbvcxz109ify]

Plug and play wins again

[@SchrodingersBox]

Plug and play > pray and spray!