So well spoken...too many folks riddle their presentations with "you know," "uh." Very thorough and easy-to-listen-to talk.

Hey it takes a lot of time just to explain a O2 sensor really you did a perfect job explaining IT its a lot more work than what it really looks like but that's the difference between a good technician and a backyard mechanic excellent work thank YOU. YOU DID a great job explaining exactly how a O2 sensor really work's

Simply the best O2 senor video I have ever seen.

Clearly illustrated... Naturally gifted teacher.. You should consider it as a full time profession!

Dear Professor, I am from Philadelphia myself originally and was glad to see your video. It aided me in understanding the issues I had with my vehicle (Ford 2015 Police Interceptor Utility). In the end I ordered the proper part online and paid a shop $50 to install the O2 sensor for me (as I had neither access to a lift nor a jack that could get my car up high enough for me to use a breaker bar to remove the O2 sensor myself, even with the proper O2 sensor removal socket in hand). Your video is highly instructive and well appreciated in no uncertain terms and thank you for effectuating its publication.

Having spent 4 years in college and 4 more in dental school learning my craft I must say you are one of the best teachers ever. I fell into this by accident and watched the whole thing just because my check engine light is currently on. Thank you so much. Now I feel like I can speak knowledgeably with the tech about my car problem when I take it in. Good job, Car Doc !

Very thoughtfully presented. I'm 71, retired and considering taking a auto mechanic course just for edification and fun at our local CC. Hope they can do as good a job expounding as you did. Thanks

I just came across this video accidentally. My goodness wasn't I glad I did. Well documented & illustrated fault finding & understanding about O2 sensor. Top man Dan. Well done.

Excellent! Easy to understand, especially for the not technically or mechanically inclined. You had my undivided attention. You being a professor I expected no less than the best!!

I have very limited knowledge and appreciate this very detailed lesson. Anyone sitting at this guy's automitive class/classroom will surely learn. Thank you!

Excellent. While you did say pin # 4 after reading it correctly as pin #2, you correctly re-checked the reference page and did exactly choose and say you chose the pin #2. You said pin # 4 once but you said and used pin # 2 twice and correctly. Someone mentioned this thinly a while ago. I know that you chose the right one and you double checked the info as you proceeded so I saw and heard an excellent mechanic being careful and rechecking the reference info on the fly. I work on my vehicles and occasionally help others(never for pay) and I warn them that while I refer to myself as a mechanic by experience, I have had very little actual training. I am in Texas and am too far and too old to get to your class and I very much regret that. This is my first viewing of one of your videos. I subscribed immediately and I hope to find more. WOW, way to go Dan Reed.

I am not an auto tech, and either a DIY guy. I watched the whole thing because you articulated how to use the diagnostic tools to fix the check engine light very well. I also noticed 559 thumbs down. Not a surprise. I think I know the reason. See, It is not you're wrong. It's because auto "stealerships" (dealerships), and crooked shops don't want you to educate the people they have been robbed with unnecessary and unjustifiable problems they occasionally made up. For one real issue found, they would have to make up two or three more to generate revenue. You're also going to receive some thumbs down from those who can't analyze or can't think outside the box. Good Job! Keep it up!

Outstanding Sir. Clearly you've played a structural role in your Automotive Academia with helping our nation's youth secure employment.

Dan. One of the best presentations I have seen. Everything was explained in simple terms. My mechanic told me I have a problem with the heater circuit in O2 sensor past the catalytic converter. So what I'll do as a quick check is remove it, get a wiring diagram from Bosch and check the resistance of the heater coil. My mechanic says he doesn't mess with that stuff. I don't know why. That's why I took it to him. The thing is I just replaced that sensor not too long ago. I talked with the man at Bosch and he's going to see what he can do for me if it is the heater circuit. Thanks for the help. Bill Piech Raleigh, NC

Brilliant explanation, thank you Sir. If you don`t know about O2 sensors after watching this video, then I don`t know what will help you. The best video on the subject I`ve found so far!!

I really enjoyed watching Dan. This guy knows his stuff and does it right

I'm new to mechanic and learning one step at the time. This is such a good video, thank you very much for explaining in details what is an O2 sensor, its different parts etc . I will surely watch other of your videos !

This must be one of the best and explicit videos on the theme that I have seen. This person is great at teaching because he really knows the science behind the theme. Great video!

so well explained finely now i know how an 02 sensor works my friend you did an excelent job and i am proud to have found you thanks to KZfaq keep it up we need more people like you geat job.

You speak slowly enough for people to catch what you are saying. And, you enunciate clearly so that folks like me can speed up the video to 1.5 to go faster. But, I can still understand everything you are saying, simply at a faster speed. I like your style of teaching. I will look for a video from you for future problems. Thank you very much.

Absolutely wonderful video. Very informative, I would give 10 stars. I have no words for this professor. I wish I could learn more about car repairs from this professor. Overall, Thank you so much for your time. I will definitely follow and watch more of these videos.

The kids under your tutelage in Philly are privileged to have you as their leader, Professor Reed. Thank you for your dedication to preparing the next generation of what used to be Mechanics, to be Engineers of Vehicles-as signified by the patch on your shoulder-and are now a vanishing breed. I am a Master Mechanic from the '60s, and licensed Aircraft & Powerplant tech, because I'm a Commercial Pilot. The root of the problem can be seen in the inane snipe below. Perfection comes at a price; all cost time. In this single video, concerning a critical element of every gasoline-powered conveyance, could become the viewer's ticket to fame and, yes, fortune. What would you have shortened, clod Criz??

I cannot believe how good this guy is and how interesting and knowledgable he is to listen to, i practically know nothing about cars but a novice could easily become confidant around an engine after listening to his teachings, superb, i am so pleased i came across this web page :)

3.5 million views and only 50,000 subs thats ridiculous. Great videos and excellent instruction.

To everyone who is commenting about this guy talking to much well that's because he loves his job. !!! He is eager to help people. I can tell he just wants to make sure everyone understands about what the check engine light does. Some of us like myself a woman who have no man around the house need a full lecture like he is giving. So if we have to take it to a mechanic we don't get well you know. Because I have been just like my transmission. The guy told me it was my transmission and it could not be rebuilt. I didn't know that. He also told me he would have to order from California I live in Texas and it would take a few days to get to his shop. Keep in mind he had not even took the transmission down. So I gave him the okay I had to have my car for work and would you believe the next day he called and said my car was ready.??? What happen to the 2 or 3 days shipment to his shop. I believe what he did was took down my transmission and it was a minor repair and fixed it and charged me for a transmission I just wish I knew if there is a way to tell if I have a new transmission on my car instead of the old one still being on there. I know its the same transmission. So Thank you for detailed information because I have no idea of car mechanics and after this video I am now well informed. I am going to attempt to fix my own oxygen sensor. thanks

This Prof. has done an exceptional job with explaining the nuances of troubleshooting and diagnosing the problem. I wish I could be his student. Great job!!

Like everyone else I thought it was an excellent demonstration video too! Key thing for me is your emphasis early on in the difference between professionally qualified technician and others (accepting that experience is important factor) - cars are sophisticated and require techs to be deep thinkers/analytical in their approach and able to reflect on their practise to complete differential diagnosis and subsequent interventions with the great technology available to support this. No surprise, I was a health professional for over 32 years before deciding to study Automotive Engineering. Codes, standards of practise and ethics come into play. There are alot of similarities where its a person or a car (and its owner that you are helping). KZfaq and these high standard videos have really helped my learning.

Thanks so much Mr Dan Reed for that best explanation.Big up

Loved the video/training! One of the best free college classes i've ever had!! You have no idea how much this means to people who can't afford expensive car care or training. This is what giving back to the community, help others is really about. Thank you so much Sir!

Great video, Dan! This is why getting a car fixed these days is expensive. This is the right way to fix an engine light. Taking a test drive would be suggested, as a final test.

Very well done. A professional Auto mechanics teacher. Easy to follow and understand. Thank you Sir.

Loved how detailed this video is. Even history of oxygen sensors! Very well done. I have a bank 1 oxygen sensor 2 heater open circuit error code. I feel ready to tackle this. Thank you!

Retired English mechanic, left the trade after 40yrs before all this stuff really took off. Try to stay updated and videos like yours are so great. You remind me of one of my college lecturers back in the sixties he had a real passion for his subject and was able to inspire all us would be mechanics..Great video thanks so much!

I am a firm believer in using antiseize. You may think this is overkill, but I will if possible, clean the threads in the exhaust pipe with a welder's pipe brush and apply a VERY thin coat to all the threads. I also apply a VERY thin coat to all the threads on the sensor. And like Dan says, don't let it get on the sensor. I have friends who know where I've been because everything was so easy to take apart. Also, when you can't loosen a sensor with conventional methods and a torch is not practical, I have used an 8 or 10 inch pipe wrench after soaking the threads with warmed up PB, which is more chemically active.

Firstly I wondered how a technician could be explaining like a professor; but vow he is really a professor!

NICELY DONE - GREAT EXPLANATION - MUST WATCH IF NEW TO O2 SENSOR - THANK YOU VERY MUCH ! ! !

Just found this video and the entire playlist. I am very fortunate to have found your work. May you be safe and well

A few other things to try if everything in this vid fails to break it loose (a GREAT vid, by the way): 1. If you are not going to reuse the old sensor, and have cut off the wires DO NOT USE A SLOTTED TYPE SOCKET! They do expand enough to slip and round off your hex if you put enough pressure on them! Just use a regular 7/8", six-side socket if you cut the wires off. 2. A slight variation to the vid, where he heats both parts: try heating the mainifold only, as much as possible, getting as little heat on the sensor as possible. Heating them both will cause both the manifold and the sensor to expand from the heat. The ideal situation is make the mainifold threads expand MORE than the sensor threads, breaking the bond more easily. 3. If that doesn't work try it again. This time when you are done heating, wrap a damp rag around the sensor (keeping it away from the manifold as much as possible) to contract the sensor threads. Try again quickly. 4. If these don't work, heat the crap out of the manifold AND the sensor until everything is as absolutely as red hot as you can get them, then douse everything with water. The intense and rapid contraction might break the bond. If you try enough things, enough times with heat, it WILL come loose. You simply have to break that bond between the threads. Just don't give up, and don't round off the hex or you will have a whole other problem. Again, nice vid. Do as he says once you have the slightest movement. Lots of oil, lots of patience, back-and-forth until you work past the corrosion.

The troubleshooting steps to check the sensor were appreciated. Very easy and quick. Thanks.

Your video saved me a lot of worry about HOW to remove the electrical connector and wire of the O2 Sensor from the frame

Great video, I am a new O2 sensor warranty engineer at Ford, I am actually learning a lot from the video! Really appreciated the content!

Man I can only say something, this video is the best of the best telling us the most complete class about the Oxygen Sensor, and everything clearly explained with easy understanding words!

Now I know what they're talkin about when I'm reading and it says lean code. When they mention fuel trim. I always read it but I never understood where it actually stands for. Now I do thank you. You are truly an educator thank you for choosing this career.

Am not a mechanic or engine enthusiast, but because on 2 occasions my Nissan developed this check engine with P0420, i am so informed right now. My local mechs will not lie any more especially on codes that are logic based, Thank you so much for the educative video. Will return once i buy new O2 Sensor

I must say this is a high quality vid for 02 sense diagnostics. Good job, Dan!👍

Oh, he's a professor; no wonder he presents so well. No ums or hesitations, a pro. I love how he compares the decimal millivolt reading to a dollar/money number ... helps people catch on quicker LOL.

THANK YOU FOR YOUR SIMPLE BUT GREAT INFO iAM 65 AND I DID NOT KNOW THAT THEY HAD HEATER IN THE SENSORS THANK YOU AGAIN FROM UK

Best ever I had, I just loved the presentation, took time, didn't bypass any process and gave all the necessary info and reasoning.

Excellent explanation and instruction Dan! Your performance in front of the camera is extremely competent with no attempt at being an internet "star", which for me, will now make me watch many more of your videos. You are a STAR! :-)

Hey Dan you seem like a good guy who likes to share honest information to other people. Thanks..

Thank you for this awesome tutor. Greetings from Lagos Nigeria 🙌

Hey super Dan you are a good instructor I am retired from U of Delaware after 8 years I am back to my old job as a senior lab tech I instruct undergrad grad post Doc in the Composites field I enjoy every day of my retire life at U of Delaware enjoy your video

Thanks so much for this video! It was very informative and helpful. You are an awesome teacher!! The kids are lucky to have someone that clearly explains, and teaches how to diagnosis, then how to properly complete necessary repairs.

Excellently produced, clear, audible speech, straightforward, sensible. This is a very helpful video. Ok its a new, clean car and in real life most sensor replacements will be on older cars and many sensors are in much more awkward places and you referred to that possibility, but the use of a new, clean vehicle made it very easy to see what was being done. Well done. Thank you. Andy in the north east of England

Dan Reed what a fantastic teacher you are I enjoy watching all of your videos

Excellently explained and learnt how O2 sensor works by watching your videos

I've watched alot of car repair videos and yours by far was the most thorough, clearly stated, accurate non bs best one i've ever seen to say at the least. Thank you so much! Keep up the great work!

One of the most informative videos I've seen yet.

your smart ass. watching your videos learn a lot about car troubleshooting. keep up the good work buddy....

I am happy to learn from your video about oxygen sensers.Alot of mechanics don't know the functions of sensers on the petro engines.This great.

Senor Reed, you are definitely an excellent instructor and I love the way you present and clarify this very valuable information regarding 02 Sensors! Love this video and this is by far one of the best videos I have seen and love the way you explain and simplify the steps and procedures you are taking in completing this type of diagnostics! Keep up this great work and I'll be looking forward to all your future videos! Happy Trails, Hasta Pronto!

I left the room for a bit and came back to this.....I watched the entire video and I don't even really care about oxygen sensors. You're an absolute legend!

Dan is the type of guy who just likes to help people.

I had a 1980 Dodge d50 pickup and the Mitsubishi equivalent. Both had an exhaust manifold with a built in cylindrical catalytic converter in the two piece exhaust manifold. I took both out and used a screwdriver to break up and remove the guts of the converter in both. Drastically improved performance of both trucks. I converted one into a convertible. It was a cool thing back in the day. FWIW, I had to do the first one because, when I checked it, the top had been melting like pudding. The makeup of the thing is like a 3D screen. That is, instead of the holes being tiny squares, they were tiny tubes, about 6-8 inches long, IIRC. But so many of the tubes were clogged from the "melting" that it created massive back pressure. So I got rid of it. :) This was in the Seattle area. They still passed emissions tests. It was also around the late 80's.

Amazing presentation laid out clear and concisely. Incredible teacher fantastic job. Thank you

Very, very informative. I like the side talk that supplements the information.

Love this presentation. This CCP video very helpful for beginners. I graduated from PCC( Pasadena City College), major in automotive technology. Now I’m truck driver, used to work for Mercedes dealer for over 20 years, specialized in automatic transmission overhaul. Can’t handle it anymore due to state of the art model come out.

Extremely informative. A car is a machine. Not a mystery. Not anymore anyway, thanks to Philly CC videos!!!

40:00 I was almost at the point of thinking you where going to further diagnose and then repair the heater of the sensor. Amazing video 👍

Absolutely brilliant! Thanks Dan, you have an excellent way of explaining things in simple terms. I really appreciated it.

Dan, you the man....I followed you instruction too the letter and fixed the bad bank 1 sensor 1 in my b2300 Mazda 2.3 liter. Thanks so much for the attention to detail

Saving to my faves.. great video !! I got adhd and sat through the whole thing.😂😂😂

Brilliant video Dan, I learnt heaps about O2 sensors. Keep up the good work!

Excellent video Mr.Reed I really appreciate the proper technique & steps to finding the source..👏🏿🤔👍🏿

Perfect analysis and video! You are awesome! Thank you very much! Keep doing this videos and helping us!

Great performance. You stayed on track and got to the meat and potatoes of the diagnosis. I'm sure this will help me in my journey to track down the issue with my truck!

Wow you’re a great teacher. Thank you

WOW! I have watched many videos for repairing my car. This one is the best and most informative I have ever seen on KZfaq!

Dan, you are the man. Technical and to the point. My GMC has a bad O2 sensor. Not too worried about it yet but it does need to be assessed. Your video gave me much insight i what I need to do. Thank you!

Excellent autoTech Professor ! Now I know why O2 sensor replacement is better for gas saving !

I want to thank you Dan Reed for the information you show how to diagnostic 02 sensor I be able to fix my problem in my car

Very well done ! I felt like I was back at tech school . You were very thorough, again very well done . Many videos are done poorly and quite frankly a waste of time . Not this one.

Thank you very much for these videos I just stumbled across... They're great... Rule #1 - Ignore whatever the customer tells you and check for yourself...

Very thorough presentation of this device & great job.👍👍🏾

Excellent video and no don't make it shorter , everything needed to be said and done .

Covers all the bases. Good !

That song in the beginning is a lot smoother than you would expect

Top shelf instruction. Thanks for the clear diagnostic approach to finding what is wrong with oxygen sensors. Excellent presentation.

Great, informative, just what I am looking for. I like the theory, and style of your presentation.

Excellent video...learned a lot!! Also a very good presenter.

U r a real master mechanic professor. Thank you!

I Started Watching This Video and Thought I Knew a lot, But .....Let Me Tell You, after Watching This Video, I Feel Like I Can Tackle any O2 Sensor Problem or Code. a Hell of a Great Job and Thank You. Thank You.

Thanks Dan very informative video and great presentation

25:30 Actually we have thousandths of a cent not hundredths of a cent regarding millivolts. Exceedingly good video presentation: quality video, great tools, and smart, well spoken, experienced, qualified technician.

This is the best video on this subject. Thank you

Best education video regarding 02 sensor.

The best way to check if the lambda sensor is functioning is to set the engine revs at around 5000 rpm , go to the rear of the car and take a big long sniff of what comes out of the tail pipe . If you pass out immediately it's not working , if it takes 5 minutes to pass out its working fine !

Clearly I understand your lesson even experienced mechanics. Appreciated.

Thanks Dan for that explanation. When you diagnose a circuit, it's easy to forget like you did about checking the Malfunction Indicator Light (MIL) or Check Engine light. I've done it also. But the proof's in the after test like you had shown! Intermittents, like I've seen before, are a different problem. I'm sure you know what I mean! Nice Diagnostics, Nice Repair.

I like this guy. Very detail oriented. Although knowledgeable, he knows how to teach the basic of his subjects to new/DIY people. Thanks. I learned a lot.