Fix P0420 Code | How To Use O2 Sensor Spacers | Project M3 Episode 2

[@JetBlackBerry]

Omg 4th try and it passed smog! Used 2 Autozone 42002 non foulers. Thank you sooo much. You're the only one who said to try diff lengths. No vids I've seen said that. On my way to get my sticker. Helllloo June 2021! Yes they're that expired.

[@HazardGarage]

LOL hell yeah! Congrats!

[@TimPool-b8z]

@@HazardGarage I installed my spacer got rid of the light but I'm having a loud hissing sound coming from my exhaust when accelerating. Any clue what it could be?

[@HazardGarage]

@@TimPool-b8z you might have an exhaust leak. Check you tightend all the bolts and check the condition of your gaskets.

[@TheWilferch]

@@HazardGarage Dorman 42002 uses an angled seat. All O2 sensors use a flat seat with crush gasket. The Dorman version built like this with flat seat and gasket is 42009. An angled seat may give you a leak against a "flat-bung" surface that wants a gasket.

[@barnabius]

I was wondering about this and didn’t even know how to word the question properly. Immediately subbed for that intro music

[@HazardGarage]

haha thanks!

[@TheWilferch]

Another thought....seems you could have used the original 90 degree "cube" style you show.....but trying it severals ways.....with or without the mini-cat-material insert ( if it came with one).....and the piece that screws into the cube can used or even not used....just plug in the sensor into the cube. That alone gives you 3 "length" variables. Also this.....some folks buy the Dorman 42009 pair and either one ( or none) of these 2 parts added as 1 or 2-stacked pieces can also be tried with the "cube". I felt the same joy you had showing " 0 " DTCs !!!!!!

[@closertothetruth9209]

finaly a video with good results

[@Sulimankhayyat]

Thank you I didn't expect that the distance is important.

[@jjakemo]

Great video man. I trying to get my codes to clear on 2015 Chevy Tahoe. Thanks for the video great information.

[@ucnhtmenow1]

I remember doing the drive cycle for my 07 Maxima after replacing the catalytic converter and it took a couple days. When the sensors finally readied, I wasn't even trying to do the cycle, I had actually given up. I think the car was just laughing at me at that point. There's really no one size fits all strategy when it comes to completing mymonitor readiness.

[@bmxonel0ve]

First video i see someone saying to play with distance of the spacers, want to mount the catless downpipe on my f31 this week and im about to order spacers, was about to order the 90 degrees, but might me too much… will see Thank u!! Nice video 🔥

[@HazardGarage]

Glad it was helpful!

[@mrrightorwrong6272]

I have a 08 honda accord bank 2 keeps coming on and off even with a new sensor will this fix the issue?

[@TheWilferch]

Trying to wrap my head around how we get a "tight" connection between the "cube" and the "bung". I see it allows angular orientation to change.....but... Should there be a gasket between the "cube" and the lock nut?...and also between the same locknut on the other side against the exhaust port "bung?.

[@arturobarroso78]

Hello thanks for your video, i replaced a converter, for a new one, i was getting p0430 with that new converter, the downstream o2 sensor is also new. So bought the L shape mini cat. spacer and now im getting the p2098 code..... jeep liberty 2005.... any advice on what to do ? Thanks

[@HazardGarage]

in the beginning you had the standard code similar to myself in the video. Meaning your cat wasnt working properly and too much gasses was hitting your sensor. Now it seems like not enough gasses are hitting your sensor. Try taking the mini cat out and seeing if you can get the sensor closer to the gas flow. Just like my car, it was a balancing trial and error act. *this isnt advice, its for entertainment purposes*

[@arturobarroso78]

@HazardGarage I'll take the mini cat out of the spacer, hopefully that keeps the light from coming back. If it comes back I'll check what codes it gives me. And play with different lengths of spacers like you said... your video is the best in all youtube, thanks a lot. .. I'll get back to you if I get a light or not, this will help so many people... just for entertainment purposes. Thanks

[@Thaboytony]

Can you provide with the exact part number you used please? Thank you

[@airyordan6291]

I put 2 spacers with steel wool on my Maserati Gt with the v8 and it only went a week. I think it burned up the steel wool when I was revving it hard. I’m about to try the mini cat. Smells like a refinery behind the car but the exhaust velocity is really high it blows mulch and rips grass out of the ground so it might need 3 spacers.

[@HazardGarage]

I dont know if the mini cats helped. For me it was just playing with the distance of the spacing. But really more modern cars are bit more sensitive so its a gamble. Frustrating, I know..

[@dunstonmunson8314]

Do I need to disconnect o2 sensor connector to put on an o2 spacer? I mean I know the sensor needs to come out to put the spacer on, but do I need to disconnect the sensor from the electrical connector end as well? Will the wires wind up tight if I try to just take out the sensor without disconnecting the wire?

[@HazardGarage]

you most likely will have to because you'll end up twisting the wire as you try to screw it on. You can try but just know if you twist too hard you can put strain the wires and wear them out or break them.

[@amelia-rose2992]

There's different lengths and elbows? What!!! This may solve my issues. The addition of the spacer was causing the P0420 to pop on. We just removed it completely, but if that doesn't work maybe we can try other sizes. Thanks for your pain.

[@HazardGarage]

Yup! If you get P0420 it means too much unburnt fuel is in your exhaust. This is what can happen if your catalytic converter stops working. If you get another CEL that mentions about being 'lean' or anything like it can't get a proper reading, then you need to move the sensor 'closer' to the exhaust flow. Play around with lengths and see what happens. It sucks and time consuming but it might work out.

[@eddieyu80]

The slow response is due to the sensor is too far from the CAT. The temperature is too low to keep sensor ceramic to be hot enough to work like a semiconductor. The spacer has to be as short as possible.

[@HazardGarage]

thanks for the explanation and you are right. When the slow response happened I shortened the length. When CAT deficiency happened, I lengthened it. Played around with this for a bit until I got the riiiiight length.

[@Toxic_doc]

It’s my upstream sensor that’s throwing the code bank 1 s1 Ever since I installed LT headers and high flow cats on my challenger I’ve gotten multiple o2 sensor codes it’s been a headache. I love the bolt on install performance has been amazing except for these annoying codes. I can’t pass inspections text in Texas. I replaced the o2 sensors and still not working. I’ll give these a try Thanks for the video.

[@HazardGarage]

never use a spacer on upstream O2 sensors! upstream sensors tend to be responsible for keeping your engine running correctly adjusting air fuel ratios. Downstream (after the catalytic converter) tend to be used solely to see if the catalytic converter is working (although highly advisable you search and see if this is the case for your car.) As shown in the video, for downstream O2 sensors, sometimes you have to play with the length to get it just right. And some cars are a lot more picky than others. Outside a tune, this is unfortunately the state of affairs. Also note, if you are using this for emissions reasons, you might not pass a visual inspection (check your local laws).

[@promiseonwuachu]

Hello, please, can I use these spaces on my car, I'm getting cat low deficiency bank 1 & 2. Please can I use this spacers and which o2 sensor should I put it? Will it stop the code if I put the spacer in the bank 3 and 4? My car comes with 4 o2 sensors.

[@DanielDroegeShow]

I have heard a few rumors about these on newer vehicles from other techs, but have not confirmed this info. On newer model cars that use air/fuel sensors instead of upstream O2 sensors are tested by the ECU by periodically sending a rich load of fuel and watching the measurement spike and compare that to the downstream O2 sensor. The downstream will not react correctly if a spacer is installed and it will still throw a code. I would love if someone had a source to this so I can confirm.

[@HazardGarage]

I cant confirm but I have heard of cars becoming more 'complicated' There is even word that some cars actually use the downstream O2 sensor somewhat in calculating A/F ratios. So I wouldnt be surprised of what you said being true or becoming more true.

[@HG-kp2kh]

hey man after you passed, did u remove the spacer?

[@HazardGarage]

youll get a light if you remove it. I left it in.

[@yagamilight1464]

, I have a question I have the p0430 because my cat is dying, i heard that you have less power if this code shows up. Does the spacer also bring the power of the car back or is just the check engine light gonne

[@HazardGarage]

some cars might do a limp/safety/reduced power mode when any CEL comes on. some cars also might use both upstream and downstream O2 sensors for fuel mapping best is to search around for information on your specific car. My understanding for the E46 M3 was that there would be no issue with power as long as the CEL was off as I did not find any thing info saying the rear O2 sensors were used for fuel mapping.

[@TimPool-b8z]

I installed my spacer got rid of the light but I'm having a loud hissing sound coming from my exhaust when accelerating. Any clue what it could be?

[@odevious8081]

Leak

[@on1ytheb3st]

Did you use copper exhaust sealant or anything to seal the O2 adapter?

[@HazardGarage]

No sealant. I did use a little anti-seize

[@on1ytheb3st]

@@HazardGarage curious how they don’t seal since it’s just threads and not crush washer

[@promiseonwuachu]

Hello, please, can I use these spaces on my car, LEXUS IS250, I'm getting cat low deficiency bank 1 & 2. Please can I use this spacers and which o2 sensor should I put it? Will it stop the code if I put the spacer in the bank 3 and 4? My car comes with 4 o2 sensors. The O2 close to the engine is 1&2 and that is where I'm getting the code.

[@HazardGarage]

These are only to be used on the REAR O2 sensors (after the cat). However, newer cars can be very tricky. It might work, it might not. For example on the M3 (which is a 2002 only) I had to try 2 different lengths and drive a total of 200+ miles to see if it worked...it sucked =(

[@promiseonwuachu]

@@HazardGarage I understand I saw a video on someone that did it on the same engine as in my car so I believe it will work. I've orderd for it already

[@HazardGarage]

@@promiseonwuachu i hope it works out for you!

[@promiseonwuachu]

@@HazardGarage you're scaring me hahaha

[@Stay_True_-]

Hello I will be installing obx headers and y pipe to my car. I bought some spacers and I would like to know at which o2 bank locations are spacers needed to avoid CEL? Because there’s down stream and up stream …Please let me know thanks! Great content btw!!!

[@HazardGarage]

Don't use spacers on the upstream O2 sensor. That is the one before the CAT. This O2 sensor is used to measure your car's Air/Fuel mixture. Downstream (after the CAT) is where you can use these.

[@Stay_True_-]

@@HazardGarage after having 02 spacers for a week I got a cel. Any fix to this?

[@HazardGarage]

@@Stay_True_- you have to keep testing different lengths. Its annoying, I'm not going to sugar coat it. cat deficiency error - means O2 spacer is too close to the exhaust stream. Needs more spacer. O2 sensor slow to respond or similar - means O2 spacing is too much. Move closer to the exhaust stream (less spacer).

[@Stay_True_-]

@@HazardGarage i replaced the o2 sensor and the code hasn’t came back…hopefully it stays away

[@JetBlackBerry]

I can't believe it didn't work for me. I thought for sure it would work. I have an 07 honda accord coupe w/P0420. My friend put 2 non foulers from Autozone connected to each other but the CEL came right back on. I'm bummed. I think it was part no 42009. I never get a break :/

[@HazardGarage]

what was the code? was it P0420 again? If so, that might mean you need to space it out even further. Maybe try a 3rd short non fouler. If you received an O2 sensor code for it not reading properly, then you'll need to shorten the length a little bit. Its all trial and error and super annoying! I had to do it like 3 times! But since I hit the right length, ive been trouble free for a year now!

[@JetBlackBerry]

@@HazardGarage Space it out even further? I can try that. I removed one of the non foulers and it came right back on. P0420 is the only code.

[@JetBlackBerry]

@@HazardGarage I got 2 more spacers, fingers crossed. My car has a new engine and a new clutch so I don't want to get rid of it yet. Yes, clutch. I ❤️ stick shift.

[@Cliffjumper]

@@JetBlackBerry did the code go away after 3 spacers?

[@JetBlackBerry]

@@Cliffjumper Yes! But 3 spacers didn't work. I used a different spacer. Everyone seems to use Autozone part# 42009, but it didn't work for me, so I tried part no. 42002 and it worked! I used both in the pack. This one was easier bc it didn't need to be drilled. It screwed on perfectly. I passed smog in CA and got my tags.

[@ucnhtmenow1]

The spacers that didn't work should work without high flow cats meaning no cats at all correct?

[@HazardGarage]

The theory is you're trying to find the "goldilocks" distance of the O2 sensor from the exhaust stream. Too close into the stream, the o2 sensor will read too much fuel, and think the cat is busted and will throw your P0420. Too far from the stream, the o2 sensor will think theres too little fuel in the exhaust and think something is wrong with the o2 sensor and throw a different code. Just right, itll be within what the car deems as a normal spec. Some cars this will be a wide window, others it will be narrow. It really is trial and error and isnt really guaranteed. *education purposes only.

[@CharlesLease-ei1ee]

No they don’t. I know because I tried it. It got me through omissions are past 10 to 12,000 miles the same code come back you’re gonna have to deal with it fix why the light is coming on or replace the cat or pull it out clean it and soak it overnight, that’s the cheapest route orders pay the big box and have one installed. I’ve done the drill and one out putting the second one in and another issue that will come up. You will have pinging on acceleration your gas mileage will drop you won’t see it right away but it will. 0:23

[@baagiiganbayar830]

hey bro awesome job. i have X6 i50 installed catless downpipe . i need to pass emission test :) where can i get sensor spacer please help me . Thank you

[@HazardGarage]

its getting harder to find such things nowadays. Your best bet might be like aliexpress or modifying some spark plug defoulers. *for education/experimentation purposes only.

[@baagiiganbayar830]

@@HazardGarage thank you 😉

[@mariomaravilla137]

Hey man so are spacers not illegal? I’m having the same issue my check engine light is on but because I have stock o2 sensors with a performance exhaust system and I was thinking about getting spacers

[@HazardGarage]

you won't pass smog checks with them.

[@TheOscar13sd]

@@HazardGarage Then how did you pass smog?

[@Dr.Ticklebum69]

Bit late to the party but the info is much appreciated. The subaru community is currently going through these headaches due to the recent green speed update that prevents tuning out the rear 02. As I'm just starting to experiment with spacers myself I'm wondering, when you were changing out spacers did you just keep resetting the code? Or did you pull a battery terminal to make sure it's fully gone? Did the car remain code free? I'm fighting an intermittent P0420 myself and I tried one of those mini cat spacers and got a lean code, hoping maybe a shorter regular spacer might help.

[@HazardGarage]

I would erase the code then do a drive cycle again. the car remained code free but after about a year I had to unplug the battery and then I started getting a code (lean - so spacer was too much). The BMWs can be finnicky but it works, just annoying to have to keep playing around with the different lengths until it works.

[@mauricios.torres4279]

Hi will the work for a 2007 328i what’s the part number of spacers thanks

[@HazardGarage]

unfortunately it looks like ebay no longer allows sellers to carry these spacers but you can still go to an auto parts store and buy spark plug 'non-foulers'. You might have to drill these a little bit to fit your sensors though. However, the concept remains the same for practically any car I can think of.

[@desolatedreams21]

did you have to do a drive cycle with each o2 sensor, or did you get a code immediately for the ones that didn’t work?

[@HazardGarage]

You generally have to drive around 30-40 miles before a CEL would be pending or show up. Very annoying process that I had to do multiple times.

[@desolatedreams21]

@@HazardGarage i need to do this on my n54 but it doesn’t seem worth the effort with how sensitive newer BMW ecus are

[@HazardGarage]

@@desolatedreams21 its super annoying i agree. But its an option thats out there for those who need it.

[@desolatedreams21]

@@HazardGarage i’m going to try it on my e92 for shits and giggles. dpfix is gonna be the most probable solution LOL

[@AimanAmirul11]

I installed the L shape spacer on catless downpipe, it didn't trigger the CEL. but when i scan with OBD it shows Slow Respons Code..i need to reset everytime if not the pops and crackles stop working LOL.. any idea which spacer should i change to?

[@HazardGarage]

slow response sounds like its not getting enough 'exhaust' air. Try a slightly shorter length or if theres any 'mini' cats try taking them out. This stuffs annoying as hell cause its a bit trial and error and driving to see if codes pop up or not. Which can take miles to find out if you got the right size. but good luck!

[@AimanAmirul11]

@@HazardGarage Thanks for your reply..i might try shorter spacer without mini cats

[@robettballard710]

The spacers caused a lean code for me? I am running long tubes with high flows. Without the spacer and the code cleared they won't come on or be green. All other monitors are ready.

[@HazardGarage]

1st make sure these are on the O2 sensors that are AFTER the CAT not before. 2nd I had to do trial and error with various lengths. It was an annoying process. O2 sensor not reading correctly or too lean? You have too long of a sensor or too much interference. Use a shorter spacer. Still getting P0420- bad cat codes? Run a little longer spacer. Also the CAT sensor is the hardest sensor to get 'ready'. On average about 50-100 miles to throw a CEL if it wasnt good. And when it was good, I had to drive about 200 miles before it switched to 'ready' Also make sure you dont have a tune on the car that disabled the rear O2 sensors. Good luck!

[@robettballard710]

Thanks for the response. I have a tune for them to be active. I guess the journey begins......

[@HazardGarage]

@@robettballard710 lol I feel you man. It took me like 4 tries to get just the right amount of length spacer. And then all those miles getting the stupid car to complete its readiness checks. Good luck!

[@robettballard710]

One more question? During these trials did you complete the cycle in one day or multiple days? Or does that matter. Thanks.

[@HazardGarage]

@@robettballard710 it doesn't matter if in a single day or over several.

[@HazardGarage]

🚨I am buying a subscriber $100 in car parts* when the channel reaches 3K, 5K and 10K subs! All you have to do is be a subscriber for a chance to be chosen!🚨 Have O2 sensor spacers or eliminators worked for you?

[@dummkompf]

lol you don't HAVE to drive 55 on the freeway. If you just drive normally, it will set eventually. The recommendation to drive 55 is just if you're trying to make it do the drive cycle more quickly, but I don't think that's even applicable to all cars.

[@HazardGarage]

There was a BMW specific drive cycle to make it go more quickly....but I can tell you after hundreds of miles...it made no difference on a BMW lol. So yeah, I would totally just drive normal lol. My subaru and Miata however, those were very quick to drive cycle just by driving around but BMW has to be difficult ya know?

[@TheAlexk780]

Any updated spacer links? Looking for the 43-45 length ones. The link listed doesn’t work unfortunately. But love the video, new subscriber here as a result of this solution.

[@HazardGarage]

wow, I just checked and looks like Amazon and eBay have removed these listings. I updated the description but you can still use spark plug non-foulers and stack them if needed. You MIGHT have to drill out the internal hole a little bit to fit the O2 sensor but this hack has been around for decades. It was just nice to have pre-fitted spacers.

[@arivera8924]

i put headers in my truck no cats and have 4 sensor do i put 4 spacers?

[@HazardGarage]

you would only need spacers on the rear o2 sensors (after the catalytic converter). The 2 front O2 sensors are for your engine air and fuel measurements, do not put spacers on those or your car will run bad.* *education purposes only.

[@mauricios.torres4279]

What’s the background song playing?

[@HazardGarage]

Benji by Dyalla

[@Gargoyle786]

Works and got rid of the 401 code I had but now car burns more gas... Gas mileage declined

[@HazardGarage]

make sure you only use this on the O2 sensor(s) responsible for monitoring your cat (usually positioned AFTER the cat) and NOT the main O2 sensors responsible for the air/fuel mixture of your car.

[@travdripdrip382]

Right on dude it worked!!!

[@HazardGarage]

Nice! First try?

[@travdripdrip382]

Yep. Straight one. The one my buddy gave me was maybe an inch longer than the strait one u used so i was worried, but after watching this i remembered him trying one and it not working. No more check engine on my NB tho

[@HazardGarage]

@@travdripdrip382 Thats awesome. Congrats!

[@mikewejko5220]

May I please get the part number from eBay for the spacers you purchased with the mini catalytic converters ? Thank you

[@HazardGarage]

unfortunately it looks like eBay and Amazon have removed these spacers from their site. You can try searching on eBay or buying from an online shop. Alternatively you can try using the non-fouler technique.

[@Cybershock102]

I installed the right angle on mine but I got the p0137 (low voltage) so I’m not sure if it’s the same issue that can be fixed with straight spacer. Here’s to hoping!

[@HazardGarage]

it might! low voltage can mean that the O2 sensor is reading to lean. Running a shorter spacer will introduce more fumes and hopefully its just riiiiight. Good luck!

[@minimanadam]

If your car is newer than an 02' , chances are NO , spacers wont work because the ecu is too precise I've tried everything, every kind and type on my r53 mini cooper and unfortunately none will work with catless exhaust, maybe a highflow cat but not catless

[@HazardGarage]

this is definitely a risk and possibility. 😣😣

[@ArunKumarSuthar]

Installed 45mm straight spacer. Got rid of p0420. But now p0138.

[@HazardGarage]

Did you have the P0138 before? You might need an o2 sensor replacement. Usually if you ran no spacer or not enough, you'd get the P0420 for cat deficiency. Too much spacer and you normally get like a P0137 (voltage too low).

[@ArunKumarSuthar]

@@HazardGarage No p0138 before. Only p0420. With 45mm spacer, voltage remains steady at 1.2 volts.

[@HazardGarage]

@@ArunKumarSuthar that is weird. Could really be a bad rear O2 sensor. From what I've seen a spacer doesnt cause a P0138. Usually youll either have the P0420 again (which means you need more spacer) or you get a P0137 (which means you have too much spacer).

[@ArunKumarSuthar]

@@HazardGarage thanks for your suggestion.

[@HailAnts]

I don't understand why he drove it around for so long to reset the code. He had an OBD2 reader, you just erase the code with it and then drive around making sure the check engine light stays off.

[@HazardGarage]

You have to drive around so that the "monitors" are set to ready. They are basically a set of tests (for emissions) that your car runs to make sure your smog equipment is all good. These tests have several criteria that must be hit before it determines its ok. The one for the catalytic converter was the hardest to set and it took couple hundred miles of driving a certain way for it to give the OK. You need these to pass smog the state smog check.

[@jayjb833]

Where did you get your spacers

[@HazardGarage]

off of ebay! check the links in the description. (I just updated them as I noticed some were dead).

[@XenomorphLV426]

@@HazardGarage eBay banned these

[@HazardGarage]

@@XenomorphLV426 I noticed that! Crazy! Guess you gotta go the 'spark plug defouler' way now. Unless savvy sellers rename these...

[@CharlesLease-ei1ee]

Don’t waste your time or effort because the code will come back. This is not a fix it’s a temporary to get used to omissions to get the light out after 10 to 12,000 miles. The light will come back guaranteed I know because I’ve done it I drilled the one to a half inch and put the other one on quite a few things will happen you’ll get pinging on acceleration, poor gas, mileage hesitation on acceleration quite a few things will change you won’t see it right away, but it will start. Don’t waste your time fix the problem why is it coming on get that fixed? If it is the cat get it replaced don’t play this game. It’s a money gimmick.

[@radziopatora]

Beginner -no need drive in the higway and do need drive long distance

[@Independenceweare]

WOW right on

[@C0yf1sh]

Yea getting those cat monitors to run their tests is a pain in the arse!!!!

[@HazardGarage]

Absolutely do not wish it on even my enemies.

[@dailydrivendiecast]

👍👍👍🌵🌵🌵

[@HazardGarage]

Whats up Leon!

[@johncaldwell277]

Sad that people like you don't care about the environment.

[@johncaldwell277]

Sad that people like you don't care about the environment.