SOLVED! Jeep Liberty 3.7L Heated Oxygen Sensor Faults - P0031 P0051 P0135 P0155

This is how I fixed a KJ 2002 Jeep Liberty Sport 3.7 4wd. If you have fault codes for both pre cat oxygen sensors (heater circuit low) watch this video and save time and money from replacing unnecessary parts and expensive dealership diagnostics. Your problem may not be where i found this one, but I show you how to test and check the entire circuit. Share what you found on yours in the comments below to help others out! If this video was helpful please like share and subscribe!
I know the video is very long, i tried to slow down and explain every step in the process that would take most experienced technicians a few minutes. Diagrams for this Jeep are at the end of the video and I will make a link so you can print them while you work.
P0031 - Oxygen (A/F) Sensor Heater Control Circuit Low (Bank 1 Sensor 1)
P0051 - Oxygen (A/F) Sensor Heater Control Circuit Low (Bank 2 Sensor 1)
P0135 - Oxygen O2 Sensor Heater Circuit Malfunction (Bank 1, Sensor 1)
P0155 - 02 Sensor Heater Circuit Malfunction (Bank 2 Sensor 1)

[@JahJah021]

This is perfect for what i am dealing with! 8yrs ago 😱😱😱 Thanks in 2024!

[@leonardnowakowski9355]

Wow, what an excellent & informative tutorial. I have an '02 Liberty as well with the same issue. The truck was stolen & the perpetrator ran into something which damaged the passenger side, lower bumper area which is exactly where you picked up your bad wiring. I'm sure my answer will be found somewhere if following your example. Thank you, I pray that I am able to break things down & follow your lead here.

[@markj284]

Thank You for this video, I was able to use your advice and trouble shoot a problem with P0031 P0037 P0051 P0057 trouble codes using this information, chased my problem down to c104 connector rubbing randomly on the valve cover of my 2005 Jeep limited. Ended up replacing the PCM didn't fix the problem, However I think the wiring issue grounding out caused it to fail. This prevented my rebuilt PCM from failing. Thank You...

[@headsup5819]

Excellent video. You've narrowed down my exact problem. I'll check you first from here forward. Ty.

[@Iseekoutthetrails]

I Got A 2007 Jeep Liberty, It Keeps Throwing a P0300 Code, I have Changed all The Oxygen Sensor, Spark Plugs, Coil Packs , Relays, Gas Cap, Battery and Radiator Cap and I keep Getting This P0300 Code, The Car Runs Great until its Warmed Up after 25 minutes and Than I get A Rough Idle. No Clue What is Causing This. Now after Watching Your Video I'm Going To Go Look For Broken Wires.

[@brianw4brian]

great you explained it well. I'd bet you'd pass the ASE A6 test. I like using the ohms for testing. it's the easiest. there is also the wiggle test. my own experience was with a Toyota 4x4. the suv would just shut off at random times. customer had it towed in. I found the issue in less than 10 minutes. wiggled knock sensor no start. wiggled the connector to distributor it started. what happens sometimes is the micro pin connectors get hogged out. it's a matter if pushing the pin to collapse a little tighter around the 12 volt wire going to power the coil... anyhow great video keep it up.

[@nrm3247]

i get the same 4 codes on my wifes 2005 tj rhd. it comes and goes intermittently. it tends to start after the jeep has been on road for a few hours and is nice and warm. it tends to clear after the heat sink and then cools. this happens 2-3 times a week for last 4 weeks now. i got oe o2 sensors and was just about to replace them all until i found your video.

[@mrsfgogo09]

Glad I found you on here was looking for a long time and no one Shows this in detail thank you I have O2 problems with my 05 liberty and I am going to go check the wires

[@davidoswald2155]

great info, i just replaced all 4 o2 sensors on my 03 Libby code p0132 came back on after we changed and cleared but going to dig into those wires this weekend and hopefully find the culprit. best video I seen yet on this kind of troubleshooting.

[@chambeers]

Any updates?

[@mozberg2191]

nice video. I got a headache trying to keep up but I sure did understand by the end

[@abrahamcoronado891]

Dealing with same problem and was following the dig along with him but my jeep doesn't have the fuse 16 😮‍💨 like not even to TPIM has the connections...

[@gonzalochacon2561]

👏👏👏 excellent tracing, hopefully all videos in KZbin where as well and professional like this.

[@germanpaz3728]

Great video I’m getting ready to do my 😅

[@prestonrasco5581]

Thanks for this helped a lot, never had anyone explain circuits so good.

[@spikeleestree8015]

The splits are from other tech's using probes to fix something else and when they probe a wire you break the insulation allowing water and air in. It will cause corrosion.

[@chambeers]

Unfortunately that happens all too often :(

[@eli25jk70]

nice video, my problem was o2 sensor b1 s1. i think I should replace sensor first and if it still throwing code then, ill check the circuit.

[@user-gx5uz6vv6u]

Pls . I need your help. How can l solve Code P0038 &P0058 for same vehicle (Jeep liberty 3.7 2004)

[@arielamerson9806]

Where did you get those wiring diagrams?! I have a 2002 Jeep liberty Limited and I just replaced all 4 o2 sensors and I'm getting p0031, p0051, p0138, and p0158 codes and I'm at a loss of what to do!

[@alfonsmc1635]

Google

[@njhandymanservice]

@ 2:03 You do and thanks for taking the time to show us.

[@3rdlegrecords125]

I have the same problem. Thank you for the great video!! A++

[@rhinohino]

Great instructional video! I just learned something new again, thanks for the lesson!

[@mountainwestminingllc710]

I have the same faults on all four of the O2 heaters. Mine is a 2005 and my power distribution panel is different. I don't have a fuse 16 and can't figure out what fuse feeds the heater circuits. Where can one find wiring diagrams specific to my year?

[@carloscastelazo5622]

Great video I have the failure on both downstream sensors but with your instructions I think is something I can do, by any chance do you have the files with the diagrams I pulled a print-screen but the resolution is not that good

[@pedrovelascoceto6576]

hello there I have a 04 jeep liberty 3.7l 2wd my head lights are blinking go's on & off

[@HawkEye3188]

Are you anywhere near The Bronx, my friends 03 Jeep Liberty sport has 13 codes and I'm pretty sure heater circuit was one or two of them... Also if you don't mind could you tell me the part #s for the OEM o2 sensors you used,,, because I wanna change all four of them for her, but I don't wanna purchased anything from autozone that might fail.... There's a easy way to get the codes on all jeeps model with a digital cluster that requires no Code reader,, all you have to do is turn the ignition to the on position 3 times and on that 3 time the codes will start displaying where you would see your mileage. Remember not to turn to fast or too slow... But bro what you did was amazing and I could definitely used the help.. Thanks EJ

[@kyresearcher]

2002 liberty sport 3.7 getting codes p0135 p0141 p0161 saying 3 sensors went bad at the same time. My wife was driving home from work and the engine began stumbling and stalled. those codes is what came up. i ohhmed all 3 and they all come right around 5, tones tested all were fine. cant seem to figure out where the problem is

[@saman5700]

Thanks mate very helpful 👍

[@greenthum39]

I would just like to say thank you so much this was THE BEST video I have ever seen you are a excellent mechanic and teacher I am a electrical engineer if anyone did not understand how every thing worked after you explain it ! They would not need to open the hood . I just wanted to say thank you so much for taking you time to make this it would seem that you enjoy your job because you are very talented and well educated as a master mechanic . I only wish your shop was closer to Louisiana because I let you work on my 2004 Jeep wrangle any time ! I was wondering how did the fuse panel get so corroded or whatever that was on it because it's covered if I'm not mistaken was it from an old dirty battery I have never lived where they put Salt or what ever they use to help with ice on the roads is that what may have happened just curious ? See I am in central Louisiana and mostly we just use sand to try to help with traction because most of the time the ice will melt by noon and then refreeze and night . Thank for your time

[@chambeers]

Thank you! I appreciate the ego boost! The fuse panels are covered but not sealed, so any road dirt and debris finds it's way inside. We also use sand but a lot more salt up here in the winter which makes everything unprotected rust and corrode. Even just plain oxygen reacts with all the different types of metals (oxidation, iron oxide, etc.). As an electrical engineer you probably run into many problems that I see on a daily basis, such as galvanic corrosion (corrosion between dissimilar metals). You'll see a lot of that with a lead battery post and a steel battery terminal, it looks like you're growing a Chia Pet on your battery. Same thing happens inside the fuse panel on a smaller scale. We have salt water air up here too, so the humidity can act as an electrolyte if it comes in contact with powered electrical circuits.

[@duendeista]

this video gave me the best information...very well done...i fixed my jeep because i watched this video...everything is explained so well and clear...thanks

[@bobschmidt7114]

Had all 4 02 sensors replaced, but i am still getting fault codes P0031 & P0051

[@zeppone4045]

You explained how the circuits work. But in reality, the chances of finding a broken wire that is somewhere in the wiring harness is slim to none. You didn’t mention this in your video. I would just run a single new wire from one connector to the other if i had a OL (Open Loop. )

[@wvjeepguy8178]

There are simple scan tools that you can move over a harness and it alerts you if a wire in the bundle is damaged

[@krappy4404]

i have the same problem i hav the codes p0031 and p0135 and i was checking your video and i noticed that i don't have the fuse 16

[@elijahantony4300]

I have errors P0132, P0031 and P1281. Does this combo mean I have to check the heater arrangement or just follow your instructions

[@carlosm7234]

Good video My frend

[@fawadbasit]

could you please share a link to these circuits ? if you still have them and reading the comments , as the video post is very old . Best video to the problem though.

[@enriqueorellana214]

Good stuff

[@johnnyjimenez4286]

Good job

[@hugowolverine23]

great video. my error is P0058 bank 2 sensor 2 and i can't find the problem

[@felixaponte5685]

Same here bought new o2semsor online. Same code popped up plus po038

[@percyflores7517]

does anybody have any problems with the IOD fuse ? i have been searching and kind of points to this diferection the radio light is out ..but the radio works then it has some issues head lights flicks and speedometer goes up and down ,,, got check it on the past coudnt find the problem ?now that the radio light out i need to know if need a new radio or ? the l key fobs stoped working as well thank you .

[@bm88stang]

great video

[@chambeers]

Thanks!

[@greenthum39]

One more thing going to share on jeep form

[@torkrench]

What year is this?

[@frankfitzpatrick5300]

I have 3. Obd2 error codes Drivers side / down stream 0/2 sensor Sensor running lean Sensor running rich Drivers side cat /conv. Intermittently running hot I am assuming replacing the 0/2 sensor should remedy all of these error codes. PLEASE COMMENT !

[@chambeers]

Sounds to me like you might have a clogged or semi-clogged cat. With the engine running use a laser thermometer and point it at each of the cats closest to the engine. If the driver and passenger side are similar in temperature by about 50 degrees F they're ok and it might be a sensor problem. If the temperature is greater than 50 degrees higher on one side, replace both cats and both sensors, they could have overheated. Make sure your spark plugs and ignition coils are in good condition also, if the fuel isn't ignited inside the cylinder the raw fuel is dumped into the exhaust and burns away on the cats which would cause them to get extremely hot. Let me know how you make out.

[@frankfitzpatrick5300]

chambeers Thanks , I will do that. I replaced 0/2 sensor Drivability much better Now show P0173 Will diagnose when i cools off today (hot&humid) Going to clean T/body & idle speed sensor then Replace coilpacks & plugs. 238.000 miles Plugs most likely look like shite ! No idea when the plugs were replaced last Thanks , I will keep you all posted . Frank

[@frankfitzpatrick5300]

@@chambeers Thanks chambers Replaced. Bank 1 / 2 driver side downstream 0/2 Sensor. Now i have a P0171-P0172 & P0131 error codes . P0131 is bank 1 /1 upstrem 0/2 sensor Already have one , so will replace tomorrow . Along with new plugs Will check coil pac's & if bad , will replace also. If that doesn't solve said issue. Then i will diagnose the circuit correctly as you did . Previous owner hit front left of Jeep . So i will possibly check wiring loom in that particular area where you had the bare frayed wires. Again , I sincerely thank you for time , energy & EXPERTISE Regarding This matter . I'll keep you posted! Frank P.S. its very Noble of you to show the less informed how to PROPERLY DIAGNOSE. ! 😀

[@mohawkmike142]

Ohm meter to test a circuit isn't a good test. You are not testing the circuit loaded. A voltage drop test is what is needed for a correct test. Faults in that corroded power center will not show up with an ohmmeter.

[@jameslimon3137]

I feel like I went back to school,

[@lizasmith2675]

Jeep definition ::just eat every penny !! Mine does anyways ..

[@MrComanche87]

Just Empty Every Pocket

[@Tristandow74]

Where do you find the wiring diagram

[@BimboKimbo]

In the jeep factory service manual. It's about 6000 pages. You might be able to find it online. If you just need a certain diagram Google would help or the jeep kj forums.

[@BimboKimbo]

You might have to dig a little more to find a copy these days because they get taken down alot but it comes in handy.

[@swpa64blueeyes]

Same problem except B1S2, changed the sensor. Now it's code P0038 on a 2006 Jeep Liberty Limited....Help Please???

[@chambeers]

Hello, two of the wires might be shorting together. With the battery disconnected disconnect the O2 sensor plug on the driver side below the first cat. Test the engine harness side and make sure the heater circuit is open (no electrical contact) and check to make sure the new sensor isn't shorted out internally on the heater circuit. It's very common to find wires touching the exhaust somewhere and two are melted together causing electrical issues.

[@williechestnut7133]

man sucks for me not to understand schematics

[@ammarabd6996]

Hello Can I communicate with you?

[@HappyHands.]

needlessly complicated, engines have become.

[@mikester9er]

Government regulation forced automakers to have these complicated emissions systems.

[@dongking6245]

We dont care about your opinion of your tools or the snap on stuff you dont want to use

[@chambeers]

It's not an opinion, it's a fact that meter leads have different resistance values and should be checked prior to diagnosing a circuit.

[@ChannelytelHD]

Mine doesn't have fuse 🤣

[@ivanangel1236]

Affectam did u replace the fuse?

[@johnnyvegas5681]

Little Blair Witch here and there but informative.

[@johnnyvegas5681]

a lot actually lol.got motion sickness at times.

[@user-ef8up7dq7y]

Stop barking about your garbage stores and get the job done