thank you for watching. I really do enjoy when I help others. makes me feel like im impacting them.

BK Johnson lol got to love my Texans

thanks for watching and supporting my channel!

Liz L. Check out my new video it's another recap on the knock sensors

Ox The knock sensors produce an AC voltage signal from this noise.

I see - very interesting! Thank you for your response. Subscribed. I guess then, that technically modern vehicles produce 2 sources of AC voltage - 1 in the alternator ahead of the regulator and 1 in the knock sensor(s), although it's in milliamps! lol

Feel free to check out my new video on knock sensors

I heard the ECU actually looks at the frequency of the voltage produced by the knock sensor. Some newer knock sensors are tuned to a specified frequency like 7Khz. Unlike the older designs which respond at all frequencies of motor vibration. 7Khz I guess is the magic frequency of engine knocking. What throws me off with this concept is I would bet that many engines might produce vibrations in that range when revved to certain rpm without even any actual engine knock occuring. I would like to know what the circuit design on the ECU side is for knock sensor circuit. Here is an interesting note for testing older ones. The older knock sensors measure a specified resistance. That needs to be fairly narrow range of ohms for the circuit to work. You can check that as shown in this video. On my 1997 Nissan Maxima. I found a plug connector on the engine harness which the knock sensor wire passes through. My sensor is under the intake manifold and a lot of trouble to access. Easy way is to turn off the engine and unplug the harness connector then measure the ohms from sensor to ground. It should read as specified in your manual. Mine was approx 500Kohms. The reason this test works is because one side of the 2 wire sensor is grounded on the block. Then measure the resistance of the ECU side of the connector to ground(with key off). Notice that it has nearly the identical resistance as the sensor? Yes its a voltage divider circuit. I suspect this is for "impedance matching". Same as audio circuits. Maximum power is transferred with the input impedance matches the signal source. This makes the circuit more sensitive to the signal which is weak since it is just produced from a peizo-electric device. If you look at a simple signal amplifier circuit. It uses a voltage divider (2 resistors in series to create a "bias voltage" at the input to a power transistor (usually the base of an NPN or PNP bjt transistor). This is just my speculation. Anyhow usually the sensor resistance to ground should be very close within 50- 100ohms of the ECU side resistance to ground. Another way to test these from Eric the Car guy as instructed by his friend @ Wells Electronics(they make knock sensors) is 1) unplug the knock sensor harness, 2) turn key on measure volts on ECU side should be 4-5 volts range) 3) plug in sensor to harness 4) back probe harness connector( key on careful not to short to ground) with a wire pin or paper clip or use piercing probe to pierce wire for sensor. 5)measure voltage. It should be approximately half what it measure open circuit with the sensor disconnected. This is correct voltages. It demonstrates that the circuit is setup as a voltage divider with equal resistance on ECU input and Sensor side of the circuit. 5) the small a.c. millivolt signal generated by the knock sensor from engine vibrations rides on this small DC voltage usually 2-2.5 volts into a signal amplifier and probably a bandpass filter circuit which selects only frequencies in a specific range I.e. 7Khz as mentioned before. Some new knock sensors have the filter built into the sensors, so wacking the block with a hammer may not actually produce any measurable millivolt ouptut from the sensor unless its in that frequency range. However this is all very interesting... NOTE 2: did you notice the knock sensor wiring has a grounded shield jacket over that piece of harness running to the sensor? Yes. The short section of wire harness is special. The shield wire travels back through the harness to chassis ground. This is used to provide a "drain" path for "induced voltages" caused by EMF interference from other electronics on the engine like the ignition coils, the starter, the alternator etc. Those other devices and even your cell phone produce radio noise which can induce high frequency voltages onto the knock sensor signal wire. The grounded shield is important. So a complete diagnosis of knock sensor problem includes measure ohms of sensor, voltage from ECU and ground on the shield wire. If the sensor ohms are not in proper range and/or the voltages are not as expected from the ECU then you have to do continuity tests on the harness to find or fix any shorts or open circuits in the harness. Therefore: You should also test the wiring and harness to verify that the shielding side has continuity to ground and not shorted to 12volts etc. This shield is equally important so your engine computer is not retarding ignition timing sporadically from false signals that are not actual engine knocking. This probably would not set a code unless it was really severely hurting engine performance. However it will reduce engine power and economy if timing is too retarded and not optimized. I would like to see someone (like Scanner Danner) demonstrate a test/measure of knock sensor circuit using an oscilloscope. Also wondering if OBD2 code scanner can monitor real time knock sensor wave form like they do for o2 sensors

Milliamps is not a Voltage, it is current. The meter reads this current and converts that value to a Voltage by the internal resistor in the meter, only current can deflect the meters' needle. This is why you never check live voltage with a meter on an Ohms setting.

Supplied voltage ac by the knock sensor same as crankshaft sensor

hey thanks for watching. and bringing in the good comments

Ur motor was know good lol threw a rod bearing

That’s why diagnosis are done to prevent throwing the parts canon. Well the knock sensor that go bad a lot are on the 5.3, 6.0 chevy engines

Oz mechanics,I wasn't directing my comment at you,I'm not saying you're ripping people off.

What I'm trying to say is if your knock sensor throws a code it doesn't always mean it's bad if there is another code with it like for example open circuit on injectors the problem is the injectors.fix the injectors and both problems are solved.the knock sensor will no longer detect an engine problem and won't throw a code.once again,knock sensors rarely go bad

Yea no problem.

Very cool ....thanks

I live in Houston tx by the way

dxraaaaa make sure it's all oem parts. Lexus/Toyota knock sensors are no joke they are stuffed in the engine compartment. When I change them out I normally have to change out other seals and gaskets due to removing the intake manifold, injectors , throttle body just to get to them. Jobs are normally expensive but just ask him to tell you to break down exactly what he's changing out

20m

Absolutely, I have a Sienna also and It is ridiculous that you still have to remove most of that stuff to also just change the back 3 spark plugs. The "engineers" who designed this should be shot.

Roger that, chief 🥵

I’m not looking forward to changing mine in my 1997 Nissan Quest! It says in my Haynes Manual to remove upper and lower intake manifold, remove coolant crossover tube.... not a quick job. But at least I’ll be able to change the leaking rear valve cover gasket. Learning something new daily.

wisenber just twist it off not that hard d

Brandon Murphy id like to know as well

Gary I just made a video today that Explains more. Should upload by tomorrow

cool thanks, I just replaced my sensors and harness but bank 2 coded again. I think I may have made the mistake by using duralast sensors but this method you explained on testing will help me determine that for sure.

Gary on what car was it on ?

05 gmc sierra 2500 w\6.0

Gary well the new video I just did was on a 06 Silverado. And it explains how to test it on the vehicle

George Cates when it comes to knock sensor I prefer to use dealer parts

Your car has the 3.0 V6, so it'll have two, one for each bank.

What about Honda Civic 1999

Check your fuel pressure.. never mind your comment is 3 years old

+tino8080 hey man thanks for watching

thanks for subscribing

Javan Trinidad 193 Toyota camry

angelisone Ever figure out your problem?

Yes, but sad news. Defective left valve cover (Japanese is building cars like American) and transmission is slipping. Valve covers are made out of cheap plastic. Spark Plugs Tubing Gasket is fused into the cover.

DaCamper Noob i never seen a knock sensor to cause a stalling problem

did you clean out where he knock sensor reside? most times is full of rust or minerals

Thanks for watching. Don’t forget to press the notification bell on my videos to receive all the new videos coming out.

Make sure to clean any rust in the hole they go in and make sure to replace the wiring harness as well

I replaced the connectors only a few years ago when I replaced the valley cover gasket & I did that silicone sealant thing to keep the moisture out of the wells that the knock sensors are screwed into,the connectors go brittle after 10 years or so. The trick with the Gen3 Chevy V8 engines is to keep a pressure cleaner or hose away from the top of the engine, ever since I became aware of that,I've had no problems with corrosion or rusted knock sensors. I've totally resealed my engine so it stays clean. The 6 litre V8 engines (e.g.L76,L77 & L98) have the knock sensors screwed into the driver & passenger side of the engine block,that's probably a better idea because the LS1 engines need to have the inlet manifold removed to replace the sensors.

Letty Ayala I would check the oil first

whats the yr make and model ?

Oz Mechanics 99 lexus es300

defective knock sensor or bad conection check the continuity on the wire if ok replace the sensor

maxnguyen22

did you use aftermarket sensors? i have to do this same job soon and every time i try an aftermarket sensor it throws lights on the es300. use actual Lexus parts and see what happens, did u fix it yet?

The threaded is closed.

I have a newer video showing the procedure on the chevys. But I always change out the sensors with original one plus the wiring harness. And also make sure that the matting surface on doesn’t have any rust

CAN CHEAP KNOCK SENSORS MAKE IT READ THAT A KNOCK SENSOR IS BAD...I CHANGED THE WIRE THAT PLUGS INTO THE KNOCK SENSOR AND THE CHECK ENGINE LIGHT CAME ON AGAIN AND SAID BANK2 AGAIN...

billy self by inputting the code online you could find out what bank it is example bank 1 or 2 and yes please change out the gaskets

Pasadena, tx

I see the same amount of knock 3.2 degrees every time no more no less

Nick Tunes idk braddah u gotta try um yourself cannot be asking everytime

Justin Jones asking what every time I have a knock sensor malfunction with multiple knock sensors replaced so I’m trying to see if it’s my harness and if I’ll have to wire straight to ecu it’s self.

Nick Tunes shit idk just do um I no care

Justin Jones ??? I’m not sure we understand each other brother sorry for the confusion

Whenever I do the Chevy knock sensors I make sure to always use ac delco. You're welcome to watch my newer knock sensor video. It's on a 5.3 engine Robert Munguia

Changing the setting on the meter only means you had the setting too low, so the meter read Overload (resistance was out of range for that setting). I don't know what the reading should be but I would guess the sensor is ok.

milky55way2012 holy son of a gun. Damn I just caught that. Damn I wish I can go back and edit it. Well I did make a new video that explains it better. Thanks for letting me know.