Don't Buy Oxygen Sensors! How to test o2 sensor

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[@b.v.g.feddie8667]

FINALLY! SOMEONE WHO ACTUALLY GETS HOW TO SHOW A ROOKIE LIKE MYSELF HOW TO CHECK FOR A FAULTY PART. THANK YOU BUDDY, EARNED ANOTHER SUB. KEEP UP THE GOOD WORK AND SHOW GUYS LIKE ME AND ALSO WALKING US THRU WHAT YOUR DOING, INSTEAD OF ASSUMING WE KNOW WHAT YOUR DOING. CLEAR AND STRAIGHT FORWARD VISUAL AND SPEAKING. YOUR AWESOME DUDE 👍🏾

[@elpidioalfonso5163]

Thank you my friend for sharing your valuable technical advice with all those who need this important help, like yours. Many thanks.

[@bernhardlist9359]

just a note, the second oxygen sensor is not the one controlling the mixture for the ECU, its function is only to see that the signal when compared to the front sensor ist flat meaning the cat is functioning. The front sensor is used to test for air/fuel ratio and tell the ECU what mixture adjustment is required. So your faultcode could only come from the upstream (front) sensor. Downstream would cause a „Cat inefficient“ code on the motor warning. have fun, Bernhard

[@methree3821]

AAh, very useful to know - gonna try cleaning my pre-cat sensor and see how that pans out!

[@Xantylon74]

He changed both so his readings were useless in this case. But aren’t there some newer cars using the downstream for the fueltrims too?

[@bernhardlist9359]

@@Xantylon74 I don’t know of any. It does not make a lot if sense since if the catalytic converter works fine all it gets is water and CO2 and there is no information about how the mixture was when it left the engine. A Lambda sensor is reading oxygen content to identify the current mixture which is only available prior to being converted by the Cat.

[@carlward9367]

@@bernhardlist9359 so should I just change my upstream O2 instead of both

[@bernhardlist9359]

@@carlward9367 Hi Carl, since I don’t know exactly what your car does it is not good for me to tell you to change parts. I had it on my Jag that just the O2 heater relay was dead which is a lot cheaper than an O2 sensor. Can you get a readout of your sensors? Any activity there? The correct thing would be that the front sensor shows a sinewave like activity and if the cat works the downstream should display almost a straight line (konstant voltage). If both sensors show the same sinewave like activity then the Cat is bad. If there is no activity shown on the upstream sensor check powersupply else it is bad.

[@paulr4353]

Why didn't you check the supply voltage to the heater? Both white wires, which should be ~12vdc. For the supply you checked the voltage on the grey and black wires on the supply side connector, which showed ~1.5Vdc. Those wires receive the voltage from the sensor, not send voltage to the sensor.

[@moabwheeling1305]

Great diagnosis Dale . You sure are teaching Sasha a lot and the cool thing in my book is that she shows a lot of interest . I have been trying to catch you live on Wednesday's but I have had a lot of doctors appointments on that day . I have about six more weeks of injections then I will be able to catch you all live again. Have a great weekend and be safe .

[@JeepSolid]

Thank you. You too!

[@robertschafer4773]

l

[@MiguelMoreno-ty5ql]

2222

[@peterlaurancearmenio5545]

An oxygen sensor is made of zirconium oxide (ZrO2), a chemical compound used to form the sensor’s thermal-driven electrochemical fuel cell. Energy is generated by the difference of oxygen inside compared to the outside. Two platinum (Pt) electrodes are placed on the ZrO2 to provide a connection for output voltage to a control module. An output voltage of 0.2 V (200 mV) DC represents a lean mixture where there is a lot of oxygen in the exhaust stream. A reading of 0.8 V (800 mV) DC represents a rich mixture where there is little or no oxygen in the exhaust stream. The ideal point is 0.45 V (450 mV) DC - this is where the quantities of air and fuel are in the optimum - or stoichiometric - ratio

[@gregh5787]

My man breaking it down

[@roadglide6895]

Auto Motive Diagnostic podcast covers narrow band O2 sensors really well. They don't actually measure oxygen, they use it as a catalyst to measure the hydrocarbons in the exhaust. There are also narrow and wide band sensors. Which ones are these?

[@seunfire]

​@@roadglide6895wide band

[@wilfredferguson282]

So 02 sensors produce electric?

[@tunafish3216]

I’ve seen people bench test them using a propane torch with out running the vehicle and it works great.

[@marymussa5118]

6pp

[@Bobcatspiritdude]

@@marymussa5118 huh ?

[@dennyc4135]

but you need to open the sensor first I supposed

[@lard1892]

WTF???

[@bobbywills2111]

Yeah removing them is the hardest part here in NYS rust belt at least

[@alouiciousjackson5812]

Oxygen sensors should be cleaned at 90K and 180K(replace them at 250K) by removing them and heating the sensing portion all around to cherry red with a propane torch, while checking response time with a volt meter. Using a meter while on the vehicle is not necessary as you can just hook up an OBD2 reader set to read live data. On an early fuel injected vehicle this method may be useful. *Edit for those not familiar with O2 sensors: there are four wires. Two are the same color, two are different colors. Connect your volt meter set to DC volts on the two wires which are different colors. Polarity doesn't matter.

[@merkey]

I have bank 1 sensor 1 0.28v bank 1 sensor 2 0.28v bank 2 sensor 1 0.04 bank 2 sensor 2 0.30v. Po300 only 03 nissan 350z . Engine cold

[@alouiciousjackson5812]

@@merkey PO300 is random multiple misfire, usually related to the ignition system but not always. How many miles on your spark plugs? What is the impedance of your coils? As far as the low sensor voltage, look at your fuel trims. How does bank 2 compare with bank 1? Spray around the intake area with carb cleaner to check for vacuum leaks. Verify the fuel trim findings by looking at the spark plugs for signs of rich or lean condition.

[@merkey]

@@alouiciousjackson5812 okay so i have brand new spark plugs and igition coils. short term fuel trim 11 0.0% and short term fuel trim 2 1 +25%. pulled plus definitely fuel but not like super black carbon rich still new

[@alouiciousjackson5812]

@@merkey short-term fuel trim bank 2 is plus 25%? Sounds like you have some bad injectors or a fuel pressure problem that it's trying to compensate for

[@alouiciousjackson5812]

@@merkey also check for vacuum leaks

[@BigBlock632]

Man I absolutely miss my 97 Cherokee County! It had the strongest 6-cylinder engine I have ever driven! Torque for days! I'll have to say that was the most reliable vehicle I ever owned! Bought it used and paid $7000 for it in 2000 and drove it till 2017 and she never left me stranded! I'd trade my 2011 Sierra Texas Edition for your blue Cherokee!

[@steveforbes8287]

This is an excellent demonstration of how to properly test the sensors works on almost every vehicle. I needed it because I am having troubles with my Toyota Camry and all indications from the OBDII lead me to the downstream sensor which is an unpleasant thing to reach. Looks like I can now at least test it before dealing with an unpleasantly hot exhaust system that needs to be dropped in order to remove said sensor. Thank you for a nice and concise video.

[@miguelquazar883]

One of the most common codes... Great video. You are a damn good teacher.

[@drwisdom1]

I found this video to be informative and a good presentation.

[@ThePeopleVerse]

Dude! There is a good reason you have almost a million views. Someone...you, finally showed (as Paul Harvey would say) the rest of the story on testing the O2 sensor. Thanks for that.

[@julianrosalesniles2335]

My OBD2 Scanner said that I needed to replace the upstream oxygen sensor. I had already bought a new oxygen sensor prior to watching this lol so I was scared I bought it for nothing but I still have the receipts just in case I want to return it.. I did what you did in this video and turns out that I need a new oxygen sensor after all 😆

[@andrewroberts2393]

Awesome! Even though I get a code on what O2 sensor to change, now I know how to use a meter to verify before swapping it out.

[@ruthspillman546]

Grest instructions. Easy to see what you are doing. Appreciate your time!!!

[@mariobueno3368]

Excellent way to describe the process and why it's not working.

[@johnmitchell8925]

thats one really nice thing about a off road vehicle you dont need tp jack it up to work on most things

[@locogonzalez3251]

Hey my guy thank you so much it worked perfect for my problem is good to have this much detail when due you sellers are trying to fix their own problems 💯👍👍👍👍

[@guesswhomartin9249]

Thank you for your teaching video... very educational. I have a suggestion for you if I may. The old sensor that no good. Don't throw it away, You can use it as a tool. Cut the connector in half, hook up the old connector to the wire coming from the computer. With alligator clips on your meter, You can read the voltage better. The old oxygen sensor becomes a tool. Just a thought.

[@teddydunn3513]

genius

[@joeyperez3974]

So it'll read the connector coming from the car only correct?? It won't read the cat. though huh?

[@commonsenseisdeadin2024]

@@joeyperez3974 correct..... What you can do in that situation is buy or go to a you pull a part lot and cut one off. There's only a few variations of connectors so there is multiple vehicles that it will work to. You can also cut the nub off and and it will work on even more vehicles. Only difference usually tends to be the clocking of the pin and length of wire for most cars. Of course not all. For a more universal female plug you can cut the whole outer shield off just won't clip in.

[@devinrogers6877]

Thanks for taking the time to post this 👍

[@Eddie81992]

Thanks this was most informative and easy to follow visually. I’m going to try it now

[@jesusaguilar9395]

Simple, clear, and to the point. Thank you.

[@hazimreitz]

This is quite informative, thanks for sharing your knowledge wise one.

[@tomarchundia1985]

Thank you for your advice. Have a great weekend

[@kitkimbrough1145]

Great video, just to add it always better to back probe instead of possibly spreading the contacts inside the connector causing a bad or faulty result

[@victoryfirst2878]

Now I can check my own O2 sensor and verify if it is faulty. Thanks for the information.

[@josedejesus6185]

Thank you very much! This is a very nice instructional video! You did It in a very simple and easy way to understand! Keep them coming……….

[@ashercohen4739]

Thanks for the video and learning is very essential

[@paulperotti3946]

Great test procedure. Thank You.

[@donaldlee6699]

Quite thorough! Apperceptive! I subscribed!

[@samuelg.sarabia3483]

Thank you for the video. Was a great help. God bless.

[@americanrights1531]

Awesome channel very easy to understand technical directions just describe thumbs up baby love jeeps

[@hhattingh]

This was useful. Thank you. Going to check out what other gold nuggets you have on your videos.

[@nhlakancube6614]

Thank you it’s clear and easy to follow

[@stephenwolfe2727]

High end test equipment is the same as I use! Great video..

[@dljones61]

i see what you did there :)

[@mariocaetano2511]

Great content. Have the blessed day!

[@joha37515]

Thanks mate, super clear explanation.

[@JM-qh5zi]

Super Good video...can you please tell what kind of wire (type or gage) did you use for testing?

[@stivi739]

Thanks for the effort dude..great vid

[@auth2368]

Excellent explanation. Thank you!

[@thehonestmechanic]

Great job on the video. We have similar style!!

[@prep1989]

fantastic explanation, what made you decide to replace both? can I get away with doing just the one with a bad/no signal? thanks again

[@denniswalker9219]

Great video and info .Excellent

[@EGMATV1]

Thank you for your teaching video.

[@joewhatsup]

Thanks for the video and explanation

[@jmcinnis621]

Great video. One of the comments was about using the OB2 scanner. Did you try this also?? Thanks

[@ronmervargas3821]

Greetings from Venezuela! good good channel about jeep especially about 242 engines

[@JeepSolid]

Thank you!

[@thelab705]

Fantastic video great job!

[@losmoore3358]

Thank u for your video. U done well.

[@drew-shourd]

Nice video, very complicated for someone like me. Can I just remove each sensor and visually inspect them for carbon build up or other? I had a cat go real bad and fouled up everything, O2 sensors can be cleaned right?

[@joeteejoetee]

Thank you very much for identifying the sensor heating and O2 sensor wires involved on a 4 wire sensor. ...but mostly the voltages that are measurable that they are absent, or hopefully changing via sensation of O2. If I replace an O2 sensor again I will cut off the sensor to re-cycle the connector and wires to connect to the stripped wires rather than probing into the connectors for the next time I troubleshoot if the ECU is sending the heater voltage to the sensor.

[@MrsBuddevil]

Are all o2 sensor connectors the same?

[@pjwoo276]

@@MrsBuddevil look up a bunch of different ones from auto zone etc. maybe you can see a difference from the pictures.

[@pjwoo276]

That's a good idea.

[@donaldwayne4219]

@@MrsBuddevil no, they vary a lot, depending on manufacturer and position as well. Front and rear sensor plugs can be the same in appearance but have different little lugs that prevent them from being interchangeable. The shroud on the after cat sensor has much smaller holes ( like pin holes ) to restrict flow around the sensor. The before cat o2 sensor shroud has holes like, vents, would be the easy way to describe it, say, the size of the smallest type of grains for example, allowing the sensor greater exposure to the exhaust gasses because this one controls the fuel mixture ratio.

[@davidruiz5383]

Great information but what were the symptoms when driving? Thanks and God Bless.

[@ProfessorKenny]

your obd scanner should display real-time voltage for each sensor on each bank, as well as fuel trims.... a multimeter externally used isn't really necessary then. But still useful if you have no scanner available.

[@Jay-zw4co]

Great point

[@Noooo23523]

yes i use a obd reader and oxygen sensor 2 under cat says 0.45v nonstop and ecu says cat is not efficient

[@nunya2814]

Not on an obd 1 system

[@casinc.2138]

Or if you have an older car like mine that is obd1 gotta love mitsubi

[@diriazi]

Great video! Thank you. Finally get it. Did your daughter learn how to do this? haha. Probably not interested. She's lucky to have a dad who can work on her over 20 year old car and drive a great Jeep. No longer make them like they used to. Loved the video. Thank you so much.

[@hammer8809]

Great video, I need to check mine now that I know how. 👍🏼🇦🇺

[@albinusclark9561]

Thank you for the video 😊

[@train4905]

A superb video sir.

[@mlez7197]

very educational video ...awesome

[@wisdomwisdom817]

Awesome job thank you so much

[@SuperBobby1974]

Thanks for making this video. Still need to find some time to replace the sensors on my XJ. No codes, no hurry 😄

[@JeepSolid]

Yep. Ain't broke don't fix. Lol 🤣

[@user-pt5nx1np5t]

Oscilloscope is a better device to check the O2 sensor voltage signal oscillating between 0.1 to 0.9 V, with a multimeter it is difficult to catch milliseconds voltage readings. Anyway thanks for your efforts.

[@Vcoldduck]

How do you know what the readings for each test should be?

[@outofthinair1]

Exactly what I needed Thank You

[@101fish9]

Nice work

[@ernestolopez-fn4hb]

Thanks good information

[@figueroafishmaster2201]

Thanks for this video

[@gueto70]

I have been chasing a misfire on a 95 Pontiac OBD1.5 for over a month. First thing I tested was probe the o2. Getting volt at the ECM signal side (and heater) of the pigtail and 2-4 millivolts from O2 side. Plugged in, probing the wire, I get .4V +/- up to .9V spraying fuel into the TB. Every source I have found said there are no volts sent to O2 but .5+/- produced by the O2 so probe reading says it is good. Apparently the o2 is as good as the information I have gotten.

[@jamesblake760]

Will this work even on a rusted oxygen sensor that the treads in the exhaust manifold are rusted together? I tried everything to get it to losen but no luck

[@crabapple6775]

wondering if I can go thru all the steps on 1 sensor at a time, because my floor jack is too heavy to move back and forth. It would mean that the 2nd and 3rd sensors I have not examined at all yet, will be getting tested warm whereas the first one I tested got the first 2 parts of the test done with a cold engine. Anxious to hear your opinion. Much appreciate your videos. Thank you.

[@MlkePortnoy]

great video thank you!

[@luiscuenca7926]

2005 Jeep Wrangler 4.0 all 4 sensors testing low on heater code P0031 - P0037-p0051-p0057 I replaced all with NGK and still lit on. I checked all the wires, disconnected the PCM, and continuity was all good, Pin 1-3-4 were good from the sensor to PCM plug and pin 2 to ground, my question is does pin 1 heater wire have 12v because I'm getting nothing as I understand on a cold start the PCM will circle a 12V + or 12V Negative signal to the heater. The circle will decrease to off as the sensor heats up. Thanks

[@dannysautorepair]

Great video thank you

[@maharaj87]

Thanks your video is a great help, I need to check my sensors as I'm getting only half the milage that I was previously getting

[@rogersingh3918]

Having the same issue, did you replace the O2 sensor and did it solve your poor gas mileage, thanks

[@ronniee2263]

Good job ! Thanks it work just like the vidio

[@brianshare-ch8bo]

For a 1994 bmw 318i which order are the camshaft crankshaft bank 1 and bank 2 knock sensors connected into the wiring harness

[@alaa_aldeen1985]

4:00 In an electronics store near my house, I found a multimeter similar to the one you have. Do you recommend buying it or buying a better type of it?

[@NateMaris]

Is that you Dale? It’s Nate. I used to work with you at Asante in Medford! This was a great video bro.

[@mcribs7811]

Oh shoot, hey Nate! How long you been out?

[@guillermodezayas6250]

What wires did you use to connect to O2 sensor for voltage?

[@andreasstylianou3735]

Hi JeepSolid, the resistance of my upstream O2 sensor reads at 7.8ohms. On the Wrangler TJ it should be between 5-7ohms. Is it a problem that the resistance is higher that 7 ohms? Does that mean there is an issue with the heated of the sensor?

[@kennethtalbott2233]

good video. thanks

[@peterlaurancearmenio5545]

Yeah thank you for teaching me that

[@carlnikolov]

Hello friend, is it ok to simply use the data stream feature on each O2 sensor using an OBDII reader? It seems like a little less trouble, or is this not an accurate diagnosis.

[@AbuDujana692]

Yup, you are correct...when you see the jumping voltage values in obd data, it means sensor is doing its duty....BUT What if it doesn't show any voltage? Or obd gives you error code for this sensor, will you straight away change the sensor??? No, you need to varify

[@Doug....]

Very well explained thanks. If the heater is disconnected then why should you expect the sensor to show voltage when running and with probes on the sensor wires. ?

[@Swampwild1]

That’s just what I was looking for. To bad no one is responding.

[@slowpoke96Z28]

Once enough warm exhaust gas passes over the sensor, it's got enough heat to start producing it's voltage. The heater is just there to get it up to operating temperature faster.

[@Doug....]

@@slowpoke96Z28 cheers mate. Good explanation 👍🇬🇧

[@pjwoo276]

at 1:45. would you only be getting the excess fuel injected momentarily, like till the ECU or PCM adjusts to the new part

[@brauerbar]

Quick question! Do you think that a faulty o2 sensor can cause a misfiring code?

[@reyrogers2806]

Imagine having a genius mechanic for a dad who can fix any problem with your car.

[@rollzolo]

Ian in full custom garage

[@carmenpereiramercado5190]

Lord! I wish I could bring my 2007 Commander to you! It needs love and the shops out here in Phoenix waiting to rip me off! I love the old girl and want her running straight! SMDH!

[@totalybitchn]

Great video A+

[@user-uq9td1mb1u]

Thanks

[@renejacques8288]

I drove my '99 Expedition like 5 hrs ago. The exhaust barely feels warm to the touch. Does resistance reading depend on temperature at the o2 sensors? The o2 sensors read 4.2 Ohms which would mean they're bad unless temperature plays a role.

[@chrisloughlin3018]

Will the gas milage become normal if bad 02 sensors are replaced in this case ?

[@adamvega775]

I have a 2007 dodge nitro 4X4 3.7, here's my question. If I replaced them with after market O2 sensors would my check engine still come on because their not the OEM from dodge. New O2 sensors I got has a didn't part #

[@bcubed72]

The rear O2 sensor isn't commanding fuel trim changes though...it monitors the efficiency of the cat. Thus if you're having fuel trim problems, I don't see how it could be the rear O2, or why to check.

[@dbbias1416]

Thank you 👍💯

[@bewbathis_3211]

Man I miss my Jeep. That bad boy undercoated? That frame looked beautiful

[@barry5643]

But shouldn't the signal FROM a post-converter sensor read a steady voltage & be at or near .45v ? If the voltage varies much or frequently or sticks high or low, I think it indicates that the converter is bad or else there's another problem upstream somewhere that the converter can't clean up.

[@thedude8439]

My 2000 XJ 4.0 130k miles was running like a champ but had a small crack in the original Duel Cat system throwing a permanent check engine light for Cat codes. No smoke, no black soot and was running like a champ. Stupidly I took it to an exhaust shop for a new replacement, close to factory Cat. Ever since they did the job the Jeep runs really rough, sounds like it's misfiring, black soot out of the tail pipe and sometimes the check engine light starts flashing? Not even comfortable driving this until I fix these new issues. Original dual cat system was unique to 2000-2001 XJ's I think..... there were 4 o2 censors in the original system, 2 upstream and 2 downstream, or something like that. The exhaust guy bypassed the front 2 o2 sensors, I think he patched up the bungholes or something and put in 2 new back o2 sensors. This is a custom exhaust shop that is well know in the area, people send their vehicles from out of state for work. Is it possible this guy is good at charging people lots of money to make their cars and trucks sound obnoxiously loud but knows nothing about my Jeep's Exhaust and totally F'ed it all up? Any advice on what to do now? How to bring my jeep back to stock-ish exhaust with no misfires and no black soot? Like I said, engine was perfect before this exhaust guy messed with the Cat and o2 sensors! He also messed up other parts of my exhaust system while working on the jeep and everything rattles like crazy. Any advice on good after market bold on close to custom exhaust in case I decide to just replace the whole system? This is a rust free/leak free/low miles garage queen and a future resto project so I wouldn't mind having a completely new system. I hear lots of people use Walker parts, any thoughts anyone? I'm doing a stock resto, as little modification as possible.

[@SorenCicchini]

Take it back to the exhaust place and tell them to sort it out. Approach them in a friendly manner letting them know that you think they accidentally forgot to hook up the sensors again and now the vehicle is running rough, giving them a chance to fix fix their "oversight". If they don't play ball, you could get threaten to get the authorities involved (Environmental Protection Agency (EPA) if you don't have decent consumer protection laws, like most of USA) or just go straight to the authorities. It is illegal to remove or defeat an emissions control device on an automobile, and if they are a decent size operation that routinely does this, I'd expect the EPA to relish prosecuting them, as they did MagnaFlow.

[@slowpoke96Z28]

Your jeep is what we call a California car. That means it's emissions control systems were made to comply with California law, which is stricter than most other states. The front 3 cylinders have their own cat and front and rear sensors, and the back 3 cylinders have their own cat and front and rear sensors. Without either front sensor connected, the computer will default to a stored program instead of paying attention to the exhaust content, and that program is only ideal for very specific conditions, and will run like dog crap in any other situation. If he left them connected but just tucked away somewhere, it's going to think the engine is lean and try to add fuel. Stored DTCs will sat which is the case. Idk the shop to say if there was malice, but they were definitely negligent. Any exhaust shop should have a basic knowledge of OBDII oxygen sensor strategy to know better than that. The only way to do what he did and get a good running vehicle would be to put a carburetor on it or an aftermarket engine management computer that doesn't require oxygen sensors.

[@paigecaplin07]

Which 02 sensor did you change. The upstream or downstream? Also which one should you change if you're getting poor gas mileage and a bit of jerking when accelerating at higher speeds (highway driving)

[@immachine1565]

He replaced downstream after the converter check for engine codes it will tell u what one to check

[@carscloseup]

Thank you, thank you, thank you!!