Thanks brother Danner thanks to your e-book and videos I know why my car was not going in to closed loop. You are a blessing too a lot of us out here brother GOD BLESS YOU !

I feel famous, my car is on youtube. Thanks again danner, this video helps me understand a large portion of what was going on with my car and i apprecieate the time you put in getting it together.

Had an issue like this on a Corvette where the front O2 sensors harnesses where switched. Engine ran rich and surged badly. ECM was trying to compensate for the wrong bank, with an aftermarket exhaust system, similar to what you had here. Several sets of O2s @ another shop and no fix.Several minutes of thinking and a quick visual inspection revealed the culprit. Swapped harness and all was well. Good find and once again great rational thinking! Keep up the great work!!!

You just saved my life, another mechanic accidentally swapped them when installing the engine, need to get more customer info first! Thank you SD, this diagnosis had me messed up...

Most stores will have assortments of zip ties by color, i.e. 6 different colors in a package. I keep a wide variety of sizes and colors on hand. When I am going to disconnect an O2 sensor, I take 2 zips of one color, and put one on the harness side, and one on the sensor side of the connector. I use different colors for each pair. (blue for left bank, green for right bank, etc.) That way, I always match them up right when reconnecting. Costs nothing, but infallible.

never used the wireless one. thanks for the comment i truly value feedback like this! and sorry i didn't answer your question before. i can't keep up any more.

You are THE MOST educational source about ECU for me sir.Thank you.

Very informative. I loved the detail and the explanation of the logic that went in to troubleshooting the problem. I learned a lot. Thanks.

Nice work Paul. I was thinking along the same lines that the sensors were reversed when I saw the downstream signal initially. Thanks for the video!

That was a nice piece of detective work!! If something can b assembled wrong, someone will do it!

Good video Dan... Sounds like every shop she went to simply pulled the code and called the O2 sensor.. No one spent any time diagnosing anything like that... Thats what my boss would do if I let him...

for a restriction, yes. for function, no but i have a case study or two in my eBook on that. i will look for a chance to do a video on it in the future

Excellent instruction video. Much appreciated and very informative. I have been working on cars since 1960s but never used graphs and other contemporary equipment as I never had that training. I have a 2004 jaguar XJ8 with all new O2 Denso sensors 234-9030 upstream but it keeps coming back up as a short in Bank one Upstream. The upstream and down stream connectors are idiot proof and can only connect grey and black male female design. But back to your Video I hope to be able to use your information to assist me using my new Foxwell NT 809 I am learning to use. There is a problem in it telling me it is shorted. Takes about 20 miles of driving after turning it off to get the light to come back on.

Great video paul, have to give you props for the e-book as well i had a 97 f150 in the shop yest. & today...it was a back burner deal i had a lot going so was pickin at it when i had time in between many other jobs. A thurs. night review from ur book and was diagnosed an out the door today...initially O2's dropping lean @ wot wld buck/jerk & miss at idle as well .#1 bad coil on driver side,#2 plugged fuel filter whiched caused plugged converters customer is gonna deal with the converters on hi

Good Morning Sir ScannerDanner take care and have a great day Sir ScannerDanner Tutorial great very helpful video thank you 🙏 👍 👏 From Nick Ayivor from London England UK 🇬🇧

Excellent Paul, that was well worth watching, another great educational video! I have no doubt that engine will be OK now!

This is exactly what what I'm getting on my scan tool. Engine was replaced before I bought it. Thanks so much for putting this up. Subscribed.

I’ll be signing up for the course soon!

I've seen this two. Mine was a Dodge Intrepid with both upstreams switched. One bank fuel trim was maxed out rich and the other was maxed out lean. It was cool :-)

Yes, changing voltage signals. Yes, frequency is number of times per second a signal (analog or digital) repeats itself.

No cat code yet. All is still well. Thanks!

fantastic! learned how to explain these graphs now, Thanks!

Good question. the reason that it didn't is because the converter is acting as a buffer in a sense. so the pcm has to add way more fuel than normal to bring it rich and take away way more fuel to make it lean because the cat was burning it off

correct although there is some theory out there that the downstream has some influence on fuel trim. I've just never seen it. I have NEVER replaced a downstream O2 to correct a fuel trim or any driveability problem

good eye man. i didn't see it when i was filming i was too focused on the upstream

Paul, What I noticed on the bank1 side is the fact that the Downstream sensor went to lean transition Before the Upstream sensor reported lean. Take for instance if I stop your recording and toggle the screen to frame 147 I will see the B1S2 had just made its lean transition. B1S1 is still reporting rich. I have to toggle the screen to frame 152 to watch the Upstream sensor report this transition. The Cat being a Buffer of sorts, it sure shows up in the time delay between the two sensors.

Awesome man. I might have a backwards sensor on mine. My downstream is going up and down and upstream are steady , surprised that I don't have CEL. just notice mine when I failed state obd smog check for o2 not ready, and also drive cycle didn't do anything

suni, paul dice q esta contento con la solucion q fue cables del sensor invertidos, thanks paul

Why does the upstream sensors go rich/lean so frequent? Great video.

Are the two sensors functionally the same? I would think that the two sensors would have connectors that are different from each other, and or, the harness lenths would be different. Your videos great, I learn a lot from them. Keep up the good work. Thanks.

Before you do anything check the O2 sensor harness connector. I replaced my bank 1 sensor 1 O2 sensor on my 2006 Kia Sedona. It was a BITCH. If your arm is small enough you can get in between the engine and the firewall from the right side of the car to remove it without removing the intake, but you'll need a ratchet, couple various size 3/8 extensions, swivel, O2 socket and a lot of persistence! But when I replaced the sensor I looked at the old one and one of the pins on the sensor cable had retracted into the connection. I used a needle nose to pull it even with the other pins. Had I done that first it probably would have been fine. So check the connector before replacing!

Great demo. I've heard of people replacing upstream O2 sensors in high mileage vehicles, with the point being that sensors tend to become lazy with age and that might affect fuel economy before it worsens enough to trigger a code. What are your thoughts? Can you quantify what the minimum switching frequency should be for a warm sensor at about 1500 RPM?

one thing I noticed watching the scannner data was that the "downstream" O2 was reporting the switch prior to the "upstream". ive had a similar problem on a Nissan Pathfinder when one bank went lean and the other rich. the upstreams were switched side to side after a valve cover gasket job.

When you unplugged the b2s1 why did b2s2 drop to zero while the b2s1 went to flat line 400 ? Thanks for the videos.

Great video! I learned a lot with this knowledge.

Awsome case study..as usual!

it was not detonating and gas mileage was good according to the owner. valve and piston damage is not a concern here. did we wash the cylinder walls down from too much fuel? possibly increasing cylinder wall and ring wear, maybe but Im not worried. drive the car and count your blessings is what i told him. oh and keep an eye on the cat. for an efficiency code

you are the best. very informative video.thanx

for sure and to be honest i didn't see it at first. when i was editing the video it was obvious

This video is informitive I learned a lot thanks for the good video

Yes, bur what other causes would give that code ? Exhaust leak, vacuum leak or dirty MAF ? No ?

I have definitely missed a couple of these and taken the long way . It does happen though.

another great video paul

How can I thank you? Sir. amazing explanation sir great ❤

great PAUL ,,good as always,,regards from your ciber friend serchmarc(peru)

WOW!!!!!!!!!!!!!!! EXCELLENT VIDEO!!!!!!!

not sure, but at around 7:18 B1S1 and B1S2 are showing pretty much a similar curves, only B1S2 is dephased a little, so it can be seen that first signal change occurs in Downstream O2, then it is mirrored in Upstream O2. it also could be a lead to the final conclusion.

Awesome teaching vid. I got a question. Wht important PIDs do you look at when checking any kind of engine performance either at idle or test driving? Thanks.

Your videos are wonderful for anyone trying to diagnose problems on their vehicle. I have a Honda 1.5 and I had a piggyback ecu on it, and a tuned exhaust, it wasn't running right so I got it back to stock and it still wouldn't run right. It was throwing a code, which was a heater code for the 02, and the efficiency was poor. So I took a multi meter and connected the heater to the 12v that I saw coming to the female of the 02, the code disappeared, but the hesitancy is still there and the bad gas mileage. It sporadically runs better once in a while. On disconnected the 02, the car runs better but gas mileage is still poor, I got a oe o2 sensor from a friend and changed it out, improvement is hardly noticeable. What am I doing wrong? Is there a way to make sure that the signal and ground are connected in the right manner? There is no code as of now.

Thanks!!! this video help me a lot .

If i remember correctly the cat does a chemical reaction where it uses the oxygen to reduce HC and CO so to make the rear o2 cycle it has to add fuel for longer to get a rise and lean it out for longer to get a drop. where as in the front it senses it right away and the computer sees drops and rises faster.

thank you!

You're the man. Great video.

hi...thanks for your info..I got a regular scanner and this is what I got from a kia 2008 sport age lx...P0133- 1:exhaust leak present in the exhaust manifold or exhaust pipe,2:front H02S failed or front or rear H02S connections reversed,3:H02S has deteriorated , is contaminated or has failed,4:P0133(1of 2) 02 circuit slow response (bank sensor 1),5:purge flow (slow) a kind help would be appreciated.. thx..God bless..happy new year...

Great video. ScannerDanner do you think the scope RomanAutomotive uses in his videos is good enough for auto repair?

If the Upstream and Downstream sensors are different, why they don t make different connectors so you can t missconnect them ?

Excellent video!

But final cat sensors signal should be around 450 mv at closed loop

yep

That be great, im saving my pennies for your ebook ever since i saw a couple videos of yours. I live in california where we do emission testing so if maybe you can show us a proper way to do a CO2 cranking test or intrusive test if your able to. Thankyou

Question, what triggers a rear O2 sensor slow response, P0139? If the rear O2 normally sits at a fairly steady voltage when would the ECU expect a rapid change?

Great video, thanks!

Excellent video, Paul, if iam right, on closed loop, ECU decides fuel trim based on upstream and downstream is used by ecu only to report how good CAT is , is my understanding right, in other words, downstream has no relation to upstream, assuming connector are connected correctly and not reversed, pls advise.

it's just a name. i use the term signal for inputs and control for outputs

The initial graphs of B1S1 and B1S2 show the B1S2 graph leading the B1S1 in time .. since the sensors were actually reversed wouldn't this lead/lag difference lead one to suspect swapped connectors?

An old video now i know Paul, and i wont hold my breath for a response as i know how busy you are these days, however i will ask anyway. My question is with one bank being reversed would you not expect to see the mirror image of the good bank's operation but simply reversed on the live data? Or is it to do with the PCM adding alot more and then alot less fuel on that bank trying to induce the upstream into reacting when the "upstream" was actually behind the cat? Cheers Dave

Hi ScannerDanner. Thanks for the video. Do you use a OBD2 scanner to draw these graphs or the test points are right on the sensor signals with a true scope? If you use the scanner, can I know the name of this tool? Thanks.

On his own... Got cut off on the last message prolly same as the owner will do with the converters lol but thank you i don't get a chance to read it very often but it is a great tool to have. Also u never answered my question.... Verus... wired or wireless???

7:22 Is it normal, that the Bank2 Sensor2 voltage goes down to 0 Volt as you left of the gas? And is the voltage in B2 S2 not to high, reading rich at 750 mv? Bank 1 Sensor 1 on my car is also reading rich 750-800 mv if i step on the gas and goes down for a sec if i left the gas, but i get a B1 Sensor 1 P0130 (electrical problem) code pretty soon indicating my upstrem sensor has a problem. A new B1 Sensor 1, same problem as with the old one. (both original 5 wire wideband sensors ) Scantool shows 14.7 (Lambda) O2 reading most of the time at idle and at 2500rpm, so sensor 1 is not reading rich. Voltage reading is not possible at wideband sensors. My Short term fuel trims are very low at -2 to -4 some times 0 at idle and goes down to - 25 (max) on 2500rpm? LTFT are not that bad - 0.8 to -4.5 . The short term do not make the short terms happy. No rich codes from the ECU, but always this P0130 B1 Sensor 1 code and it goes in open loop again after clearing codes after a while if i drive the car. Do i have to reset the Fuel trims? VW Beetle convertible 2005 with a 1.6L engine.

Good info, thanks!!

P0133 O2 Bank 1 Sensor 1 Slow Response Live Data Fuel System: Closed Loop - Fault O2B1S1: Oscillating between 0.1(mV) to 0.9(mV). Also I snapped the throttle and the reaction seems right. O2B1S2: Fixed at 0(mV). Caused Lean (Vacuum Leak) and Rich (Propane) conditions and it remains at 0(mV). PS: Costumer said that 02B1S1 has been replaced 3 months ago with a used one. All in all, should I put a new 02B1S2 even when the DTC says 02B1S1 Slow Response?

My question is, is why would you waste money on aftermarket exhaust on that lol

my car has a code stored and its a P0133. However when i check the 02 sensors, bank 1 shows v 0.459 (at idle doesnt go above 500 or below 400) and bank 2 fluctuates from 0.800 to .950. i tried cleaning maf but nothing, my car idles fine but goes from 600 to 630 to 580 to 630 and like that

@scannerdanner also I have fuel trim down packed stft & ltft I could go verbatim with that section I have learned a hole lot in a short amount of time from the scannerdanner institution ..

Why is the amplitude on the downstream sensors on B1 & B2 so low at the end of the vid? Shouldn't they be around 0.5v?

Great. I thought something was wrong when u unplug d sensor. Because the downstream sensor stop responding.

I have checked a few cars lately and noticed 2 had voltage on the heater circuit wiring, vehicle side, with the sensor disconnected and it showing as heater active in live data. Everything checks out good, wiring, sensor, etc etc. stuck!!!!!!!

Great and very smart.

Do you test sensors while at idle speed, 2000 rpms or drivin down the road at 1500 rpms or so? I only have one bank. My #1 at idle spikes amplitude about every 9 second intervials (going between .2 and .8) At 2000rpms #1 has frequency changes every 3 secs. between .1 and .9. While driving down the road at 1500 rpms the #1 and #2 mimmic one another. #2 stays steady at .75 volts while idle and 1500 rpms while in park. Any direction about this data?

@ scannerdanner let's say crank sensor( signal) sends out a squre wave it is made up of voltage wright ?? And frequency is how fast it happens a second and or m/s correct ? ?

So would it correct to say that the connectors for the upstream and downstream O2 sensors are the same?

@ scannerdanner when the term (signal) is used, no matter how small or how fast .. Signal is a form of measurable voltage correct??

Wouldn't be the B2 S2 switch rapidly in the scan data if those sensors were reversed?

I don't like it. too many variables. you can have a cat pass that test and still need to be replaced (due to catalyst efficiency codes). Also it isn't a good test for a plugged cat either. it tells you something, just no enough in my opinion.

i started getting these codes after i ran some gumout fuel treatment in my gas. the problem went away when iran my truck untile the gas light started flashing an refueled

Now a quick question, Would this also attribute to a P1133 code as well?

I have a 98 dodge ram 1500 with 5.2. Pulls a po171 code lean bank one slow response. I have replaced every sensor , vacuum leaks,idle control valve, catalytic converter, gasket under throttle body. Mas sensor. Can undo battery put back on truck runs great for fifty miles engine light comes on idles up and down, gets 5 mpg and reads lean bank one code. There's nothing else to replace that I know of. Help. Short term fuel reads 32.5 long term 0.0.

So can he now put the aftermarket exhaust back on and not have trouble?

Still no cat code guys, just talked to the owner today

any videos on properly checking CATs?

Hey i got a tucson that pop up the engine light just the day i change the fuel brand, and trow p0133 code, solw response B1/S1 i change the O2 sensor and come back to my previous fuel brand, was fine for around a month and then the light popup again. Same code same sensor =( ... and i dunno why, could you help me plz?

What?! I Didn't Know Bruce Willis Taught Auto Repair!

Excelent vidio

looking for what pins I need to test (Volt Meter) on a 4 wire Hyundai Sedona 08, o2 sensor B2S1 harness. I believe harness is bad. new sensor OEM Hyundai part. Any help would be appreciated.

my car is a tiburon 2001 and has the code p0134 and the o2 sensor was changed but still does not pass smog what can i do?

Rough acceleration no pick up ,bad gas mileage long term fuel trim settling at 2 percent no codes what could be the problem.fuel pressure ok

Trying this out on my 2017 Dodge journey.

where are you located at im having an o2 problem wih an 04 tiburon v6

buen video .. cual fue la solucion ?

Pittsburgh PA Rosedale Technical Institute