Absolutely great demo on o2 sensor. Was ASE cert mech for 25 yrs. Often found mechanics/teachers made assumptions on trainees basic knowledge. It was impressive you took the time to give detailed explanation. You would make a great teacher. Wish I had you as a forman when I had my shop. Don't think you were born yet. Lol Thank you
LOL for real! I wish you the best and look forward to watching more vids. I have been out of commision with long cancer battle but doing fine now. After over ten years I have to do a lot of retraining. Things have changed a lot as you know. Will definitely be watching and responding in the future. Thanks again👍
this is a great explanation, the heater resistance is round about 4 ohms but does vary slightly from sensor to sensor, the sensor reading will rapidly change once the sensor is fully heated all the way around, using the blowtorch is definitely a near as damn it simulation of what the sensor will be experiencing in the exhaust manifold, this is a great way to test an existing sensor and a brand new one before fitting it, it is also a good idea to check the resistance reading of the sensor wires as there should be no resistance reading across it, if it does have resistance then it means that there is carbon crud bridging the sensor wire itself and this build up on an old sensor will cause false readings to the ecu.
Wells tech published VHS tapes on this method back in the OBD1 days, and I found the same thing as you - during testing of sensors that were "sluggish", the heat from the flame (making the o2 sensor cherry red) literally burned off deposits, and "fixed" sluggish sensors (sort of like the self-clean cycle in your kitchen oven). During normal operation, EGT's on a gasoline engine don't get hot enough to burn off these deposits that can foul a sensor over time... but your torch with the pinpoint flame can, and the test procedure itself "fixes" many of the sensors that trip an OBD code for "sluggish", or "slow response". Obviously not going to fix an "open heater" though...BTW - don't bang on the exhaust pipe, or use a hammer on your wrench, or drop the sensor when removing it...or you WILL have an open heater circuit by the time you want to reinstall it... ask me how I know...
The best way to test the sensor is to backprobe the signal wires with it in the car and the engine RPM held above idle. The sensor could be producing a good signal, but the wiring to the PCM could be bad, preventing the signal from getting there. A scan tool is great, but that doesn't always mean the signal reported to the scan tool is correct.
I think you did a good job of explaining and keeping the methods and results in perspective! It may not catch all problems but it will save lots of $ for lots of folks.
I used the four wire explanation and parts and found two bad sensors. And better to hold torch below sensor head to create a fire shield rather to one side around sensor head! Thanks for taking time to educate the public.
An analog meter with a needle would show if the sensor has a faster reaction. That's the downside of the digital multi meters, you're not only looking at how fast the component is switching, the digital meter has a limited refresh rate.
A scan tool is the best way to test it with the O2 sensor(s) in situ. If it's both a code reader & one that scans live data,then it will tell you if the sensor is at fault or whether they are reporting a lean mixture due to an air leak or bad fuel pressure. For example , code for a MAF meter & an O2 sensor reporting a lean mixture will tell you that you may have an air leak.
Great video, really helps me! I'm chasing a P2195 (Oxygen Sensor Biased/Stuck Lean, Bank 1, Sensor 1) on my Ford Focus. I've eliminated all other possible causes (vac leaks, exhaust leaks, etc) and have been scratching my head. I replaced my upstream sensor before anything, but I used the cheapest one I could find. This might be my problem, so I'm doing this procedure to check it. Thanks from a new subscriber!
Thanks for the info. Very helpful. just in case no one has mentioned it, the heating effect of a resistance is Watts=(volts x volts) / Resistance. For a 7.2ohm resistance on a 12volt system this is 20Watts. This is a low heating effect, but added to the heat from the exhaust gases I guess it will achieve a two to three hundred degrees celsius.
The O2 sensor's sensing ability comes about by producing a small voltage proportionate to the exhaust oxygen content. In other words, if the oxygen content is low it produces a high voltage (0.90 Volts - Rich mixture) and if the oxygen content is high it produces a low voltage (0.10 Volts - Lean mixture). Give time for the torch to burn off carbon and heat the tip all around and not just one side.
You're a good instructor, I'm giving up on the forums and shops, they've all become jerks who just throw parts at things. I'm hoping this is my problem, I've tried new MAF sensor for P0171 because a shop wanted $500 for that and valve cover gasket (not needed), so I knew they were just throwing parts, at my expense. But I thought 'how can I test sensor without scanner?' I suspect these at 180k miles before my MAF sensor because I also got cat codes in past, like 'catalytic inefficiency' or something. I guess it could be MAF but I've tried two.
HEY! You are OVERHEATING the sensor tip, and also RISKING it because you are overheating only ONE SIDE, and that stresses the ceramic inside! The PROPER way is to Only heat to a dull, dark red, and no more and doing it in a well shaded room to be able to see the first subtle red color just appearing and then withdrawing the flame immedoately!. Heating and turning the sensor to heat its tip area UNIFORMLY around, and not concentrating the heat at one side prevents stressing the ceramic inside, as it is fragile. You may add the caution about not heating the rear portion (behind the hexagon), as you could damage the heater element, thus, the only portion to heat, is the very tip of the sensor, also trying to make the tip of the flame to enter inside the holes, in order to decarbonize the ceramic inside the outer metal jacket, that cover is only there to protect the ceramic and its delicate precious metal deposits, which are what generates the voltage signal. Someone could presume that heating to bright red color didn't damagep his sensor, but not all sensors are so rugged as the factory installed ones, the after market ones tend to be less rugged (and sometimes less durable too!) Best wishes.
If I wire a bunch of 02 sensors in series than throw them into a fire, can they create enough voltage to power my daughter's boyfriend metal camp bed? Asking for a friend.
Enrique Oh yeh bud, they will produce between 1.5 and 3.2 KW which will be enough to warm the bed, cook the dinner and keep the barn warm too for the cow, the goats, the three ducks and the newly born piglets...it's cold down there in Alaska buddy!
please, is the voltage also measured on the two white wires as resistance? Is it enough to use a candle to create a flame? Next time do a test on the Map and Maf sensor thanks for the video👍
I think that certain time you are refering to is 0ne second. since most obd2 oxygen sensor now has heater ciruit element built in. you can identify them by the pair of either black or white wires. Not just WHITE.
I have a BlueDriver Bluetooth scanner but want to upgrade, what do you recommend as a good all around scanner that has good graphing capability ? Second my daughters 2011 Kia Sorento has basically really slow acceleration, no power on hills, the only code is P0170 which could be bad O2 sensor, bad Maf sensor, vacuum leak, etc, could that throw it into limp mode, I own 2 Optimas and a Santa Fe and even with bad O2 sensors they haven't lost power. Could it be transmission ?
So when he heats the sensor is it actually creating voltage or does the circuit lower resistance so the multimeter can push the voltage through? Could you also do this test with the multimeter set to measure ohms?
On a 2012 Acura TSX 2.4L with the old upstream O2 sensor (2 black wires, 1 blue wire, 1 white wire) still installed in the exhaust I tested the resistance between the blue and white wires with the engine off and while the engine was running. Both conditions showed infinite resistance (open loop) which I believe indicates it was bad and was the reason I was getting a P0420 check engine light. When I installed the new O2 sensor there was infinite resistance with the engine off and showed a small decrease in resistance with the engine running with higher decreases as the rpms increased. When I tested for voltage I got no indications.
Correct me if I'm wrong but a o2 sensor do NOT measure the o2 content it simply heats up witch changes the amount of voltage going to the ECU, witch will determine how much feul goes into the system ......
So I’m presuming both my upstream O2 sensors are bad because neither produce a voltage at all, it just stays at 0.0. While both downstream o2 sensors does show a voltage that fluctuates as I’m driving.
Great vid on O2 sensors. Is it a bad idea to just replace all O2 sensors together in one fell swoop? Or just do the specific O2 sensor that triggered a failure? Just recently it tripped the downstream O2 sensor. I just got a used hi-mile 2009 Camry (175,000 miles) and did a huge tuneup. Im in the mode of replacing lots of items to ensure I know the baseline health of the vehicle. -----Thanks & keep up the great work.
My car is reading no activity from my 02 sensor that I just installed. The old one was throwing a code but it at least had activity. I tested the new o2 and it read 0.00 and then barely moved up to 0.01 to the highest it reached was 0.13 then to 0.03 and then 0.00 right away. It's that a bad o2 sensor? The brand new one?
Found this video diagnosing a P1135 fault code on my OBD II( 2003 toyota camry 2.4l). I started out by replacing my catalytic converter and the upstream (bank 1, sensor 1) I already replaced it but the code still persists.
O2 sensors get cleaned in temperature above 400'c city driving on low revs is not good for them especially on LPG-that's what I did:-) at first O2 sensor was cold what you did with propane torch is not only heat him up but cleaning :-) so at first was lazy because was cold and dirty... Is not that easy to reach 400'c on 1.3 petrol yaris on motorway :-) I did the same by giving my O2 sensor good blast with propane torch and it works a lot better!!! Good video mate! Thumbs up!
Hello any advice... I have a 2005 Trailblazer and getting codes : P0153 and P0054 and P0053. I recently placed both O2 sensors and still have the codes. Could it be the Cat?
So does the sensor itself produce voltage when it gets hot? When testing it did not seem that you added voltage but only checked what was coming from the sensor.
He does state a couple times that the sensor does generate the voltage. The voltage is what the computer is looking at to determine how rich or lean the fuel:air ratio needs to be. The sensor produces the voltage.
Great video! I have a 2006 Kia spectra 2.0l with codes p0171 and p2243. I have a 5wire oxygen sensor for the upstream. Call pls tell me how to test this sensor?
Hey bro, do you stay in san diego cuz i have a 04 vw gti thats giving me a random misfire code p0300 and was wondering if you can take a look at it and maybe make a video using the car on diagnosing this code, im not rerally sure how to get ahold of you maybe just respond to this comment and well go from there if its something you can help me out with, thanks.
Most engine management issues seem to be related to carbon biuld up.Carbon is impervious to acid but hydrogen peroxide should burn it.Does anyone have any knowledge in this area?
Bro i drove 2000 miles in 2 weeks i did 2 stp ultra injector cleaners with 80 gallons of gas, took me 500 dlls of gas but kept.it full all the time, the jerking i felt that felt uncommon, was gone after those 2000 miles, car ran leaner, and that was prior to changing both my o2 sensors
Hi There. Great video. I'm also interested at this moment about cold engine and hesitation when good idle but then increasing RPM which makes it go rough. As I understand it, the O2's, FPR and EGR have no input until they reach operating conditions. Also how should downstream O2's behave as mine is 290mV generally. If it needs to be high say 900mV then could I make a potential divider and produce the 900mV to see if it ineed makes a difference. I don't know what current would be needed yet in order to make the devider. I had a 1131code swirl valve and when I cleared it as I needed to for the MOT it went as above. Also now and before, it went slow up hills and hesitates. Thanks a lot for any info.
Where would you find the specifications on your car I guess on the internet what's a good oscilloscope to check the engine if it's not too expensive for the Weekend Warrior on cars
In a car the wires for upstream CC are. 1. pump current 2. sensor voltage negative 3. heater negative 4. heater positive 5. compensating current 6. Lambda control, Can you explain what is the use of so many wire. why not only 2 or 3 ?
I recently got a new ECU installed and after a few months I got a check engine light with the p0420 code and I was wondering if it has something to do with the o2 sensor or more to do with the catalytic converter? I own a 2015 lancer.
How do you check it on a 1995 vehicle that DONT have a scanner connection? My system is a OBDI system...I guess I could unplug it and see if it runs better or changes....I have a miss...at idle..or any speed or any acceleration...It was missing on 1 cylinder before I replaces the spark plugs...but It still makes a 'bump' or miss once in a while...
i'm not good in hearing English, would you please let me know: 1. when you measure Ohm at 3:12', which wire colors do you connect to? 2. when you measure Volt at 5:02', which wire colors do you connect to? Thank you from Vietnam!
Yar Holiyan yes sir, i have one question about operation principle. as i know: black and gray wires will send Volt signal to ECU, ECU will adjust Fuel consumption to Engine. So what about the Two white wires? what do they do?
@@yarholiyan5438 yes sir, so one white wire need +12Vdc the other one white need -12Vdc, right? i just test a AFR testing tool by myself (1 sensor like this + 1 digital display), power by a outside 12V battery, sensor put outside motorbike exhaust. the volt from sensor is only 0.01V-0.04V (not normal) although the motorbike works great (low and high rpm). would you give me some advises?
Yes, rough idle/cut-out during idle can be a common reaction to failing O2 sensor. Your car mixes fuel/air ratio based on data from the O2 sensor. If it mixes too lean (not enough fuel), the ratio may not be enough to continue firing, and the engine may even die completely. If mix is too rich (not enough air), incomplete combustion can occur. This may happen more commonly when first driving (especially if your O2 sensor is an unheated one), before engine & exhaust reaches normal operating temperature.
thanks for video, enjoy your work. i unplug my upstream sensor and chevy aveo runs better. plugged in engine stalls put in another sensor does same thing. 60,000 miles on car. plugs and injectors must be good, right since it runs well when sensor is unplugged. what do i look for? could it be a clogged c. converter. i changed plugs 3 weeks before 02 sensor issue. the radiator was changed a couple of days earlier. your thoughts? thanks.
+Scott Watkins did u figure out what it was? one thing u could have done was check exhaust back pressure and below 3psi is good reading. This test tells you if your exhaust is restricted.
Hi, I just did this test on my o2 sensor, and is the voltage supposed to go back up on it owen after it drops down to zero? I did the test just like you and the voltage went up to .93v and immediately droped to 0v but then started climbing back up to .23v for about a minute and then started going back down to zero which took another minute.
99% people don't carry multimeter so lets cut short. Some indications when u need to check O2 sensor are when Cylinder Misfire, Engine Hesitation, Lack of Acceleration Power and Black Smoke from silencer. MIL is on. Remove the O2 sensor and see if its become white then its time to replace it.
I have 2002 Pontiac Bonneville sle 3.8 .their is a loud bang and the motor will not crank to me it feels like it is out of time. I know the wires are in the right plugs i put new plugs and wires .pleas how do I fix this what do U think I am doing wrong
Hi Imma getting 1.4 ohms or 14ohms..... then voltage is 1volt when temp gun sez 260++ all the way to 585 F is that okay? help peeps.... I applied 12v on the heater and it heated to about 40 to 60 that okay?
Thanks man! My 4 wire Ford o2 finally reaches .9v but it takes several minutes for it to go down to .1v. 05 Ford 500 o2 code p2197 stuck lean. Running I have fuel coming out the tail pipe. When I took the o2 out it was drenched in gas.
Blade could be bad injectors that are stuck open or bad electrical connection at the injector that forces them to always be open. You might get misfiring but that really depends
Thanks for the reply. Turns out it was a bad PCM. I found 5 skinned wires in the PCM engine harness where it lays on the AC line right beside the low side port near the firewall. Also it turns out that its a very common issue with a Ford 500. So if you know someone with a Ford 500 warn them that the harness needs routing off the AC line. If this one had gone much longer it would soon have worn a hole in the AC line. Thanks again for the advice.
Yea this was extremely dangerous! In just a few minutes of running the engine, it would put a 1/2 inch of gasoline in a large bowl that I had placed under the tail pipe. I took the fuel rail out first and and pressurized it to 40 psi which is what the vehicle runs at and pulsed the injectors over and over. So I knew they were working fine. I don't have an injector tester just a home made 9v on and off pulser that I can plug up individually to each injector..
@HexagramMan I replaced the computer. It was keeping one injector open full time. found 3 wires in the injector wiring harness that were rubbed through and shorted to ground near the firewall. (common on Ford 500) I repaired those wires and that one cylinder stayed on full time. I also with the harness unplugged at both ends tested to make sure none of the wires were shorted to ground. #5 injector was getting a full time non pulsing ground strait from the computer. Is it possible that fixing the shorted wires would have fixed the car without replacing the computer? I don't think so. It simply would not run right until after changing the computer. There were some other codes going on that I can't remember right now but after changing the computer it ran good. It still took a long time to burn all the gas out of the tail pipe and for it to quit smoking. If I could get 1/2 inch in a bucket in a few minutes the tail pipe had to be full of gas in the low areas.
So this test applies to 1, 2, 3, and 4 wire sensors? And does the speed of the voltage rise and drop determine if a sensor is bad or not? Also, is there one common thing that show up with a bad sensor, like not reaching a certain voltage, or going from hot-to-cold-to-hot too slow, etc.? Thanks.
Can someone please help. I have a 2006 Suburu Impreza R with a 2010 Impreza engine in it. It’s throwing the code P0031 (heated O2 sensor circuit low bank 1 sensor 1). I’ve tested the harness for power with the ignition on and gotten 12.8 V and then the resistance on the sensor with a reading of 2.2 Ohms. What else could be causing the problem? It’s driving me nuts. The engine struggled for power under 3K rpm in 1st-3rd gear. I reset everything and cleared the code to see if it did anything and now the car is running like it’s brand new, the P0031 code is back as a pending code however it’s no longer causing a CEL on the dash. What other diagnostics can I do?
The other youtube video says if you ohm out the wrong leads you will ruin the sensor. It's very sensitive to any stray voltage at all. Have you heard that or is it a myth ?
+FightClub MeetsHere : I though to ohm out any circuit is to check for continuity, meaning there is electrical contact. The O2 sensor doesn't have any power source when cold so I can't imagine it will be damage. On a sensitive electronic cuicuit board and when it's powered on, you can do damage if you ohm out a wrong pair or pins.
A Het gu would be better for heating the sensor. The propane torch burns almost all the air so you would get a reading that indicates a rich mixture. A hear gun only heats the air, and you would get a lean indication.
can you rip open the small openings in those so that they work better is my question.I got some piece of shit ones online made in america off ebay they arn't from china but they might as well be and I am going to replace them anyway so I thought I would mess with them a little bit and see if the codes go away I got a new cat and new manifold and new maf and new air box and air filter and a bunch of other new parts but I think opening the small opening on the sensor just a tad will help reply asap thanks
