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Often times I get cars brought in that the customer states they have to keep changing a fuse. Or we will get them in from other shops where is was diagnosed as a bad fuse. We all know that fuses do not blow for no reason. 100% of the time there is a short to ground or an issue that is causing overcurrent in the circuit and that is what causes the fuse to blow. Well in this case someone "fixed" the car but seemingly forgot to fix it all the way. You'll see.
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2009 Nissan It's a Rogue. It's a two, four, two, five something. It's a four cylinder. It's big money.

Lights on, wants it inspected. Uh, the good news is they've cleared the codes for us, so that's always helpful, right? So we've got three monitors that are not complete, but we also have five trouble codes in it, so that's always helpful when the customer erases the codes before they bring it in. Let's see what we have for codes here. We're just looking at generic data.

Uh, so we can always check stuff like this because we have to make our customer aware now. Well, you've got, you know, five codes. But the drive cycle is not finished. So we have O2 Sensor One I think one just circuit Po130 No.

31 oh 37043 and 1148. it's 11 48 closed loop bank Once it must be it's not going in closed loop. but we've got uh O2 heater control circuit low for Sensor One Sensor two and sensor three. Well play with the gambling man.

I bet it probably has all brand new. it's aftermarket Amazon O2 sensors in it so let's have a quick look there. Getting to be a common theme around here. Oh look at that old two sensor is old and Rusty so that's good.

Oh this looks OG Oh wow, this is the first. all they've been doing is clearing codes and driving. It must be so that's good. Uh, of course we can't see the third O2 sensor.

It must be down underneath somewheres. However, when I see something like this circuit low circuit, low circuit low I'm assuming that could be wrong, but it would be my guess that all three of those O2 heaters run off from the same power source and that power source is probably missing via blown fuse or a wire rubbed through on the dipstick blowing the fuse. That's it. Anything there.

Oops. Just pop that connector off. Idiot Just wanted to see I know that's just all brown and Rusty that back on. A little visual here just to see if there's anything obvious.

But yeah, and see how that wire lays her up against that dipstick. So I thought, maybe that's rubbed through, but that's what I'm suspecting so well. that's much visuals. We're gonna go.

let's find the fuse box he hides down there I Think it needs to cost him an Ipdm. you're a part module. Uh, let's find a wire diagram first and foremost and then see what powers those. see if they are missing power which I assume based on the codes and then figure out why.

So here's what I found. Um, do 63 15 amp. Follow that little guy down. Okay, here's all three oxygen sensors must be California because it has oxygen sensor number three and all I did is look at the wire that's common with all of them, which is this brown wire.

So we highlight that and then we come back up that comes directly from a fuse Fuse 63 in the Ipdm Intelligent Power Distribution module in the engine room left side View 63 must be down here. So let me get this little guy out of the way. We'll pull out these little Clips here and we'll dig that out. and I believe you gotta take them out.

flip them over and we'll find that fuse, see if that fuse is blown, and then we'll go from there. Oh that one bro, you need that? Nope, they don't belong in there anyways. so these are not. You know, the factory push Nails We'll uh, put a different one in there.

Not a big deal. What's up? Oh, there's one more folks. this is more like the factory style would be. You know, possibly it doesn't really matter because 90 of the time they're missing anyways.

like misses all up there for a minute. All right, let's see. Fuse Number 63. Of course they're not labeled by numbers, but it says here: O2 Sensor 115 amp Third one up and what do you know? it's open.

Let's get a pair of pliers. Pull that out. Okay, it's a regular. She's blowing wide open so that's good.

A Little bit of dangerously. we've got our fuse buddy here. She's got a 20 Amper in it, but it's very momentarily going to stick that in there if it'll fit. Come on.

Phil Negative Ghost Rider We need to get an extension so the way this is designed, it won't fit down in the Box Let me get something different. Okay, that one goes down in there. So now momentarily stick this in here. There's no current being drawn currently because the O2 heaters are not on.

I'm going to pull the fuse out. Uh, we could probably use bi-directional controls, but let's just go ahead and start the car all right. It looks like we have control because the light's blinking so it's on the ground and we have an average 0.14 amps that does not seem correct at all. O2 Heaters I Mean if all three of them were on, we should have at least three to four amps.

Probably closer to three amps, but we're only pulling a tenth of an amp. That doesn't seem right. Put those around. so it's not really negative here.

But yeah, it's only showing a tenth of one amp. That's kind of bizarre. Let me shut it off for a second folks. So we're going to do this a little different folks.

I'm not a big fan of running a fuse. that's you know, way well. not way overrated, but at least overrated for the circuit design. So I put a 15 amp here just in this.

Loop Now I Think we're not seeing the full current draw because we've seen this Led. You know, flashing. You know, indicating that fuse is open. but we saw it flashing and that indicates to me that these are you know, clearly, duty cycle controlled heater circuit.

So we're probably not seeing the full Spectrum here. But let's um, let's just do this. Let's throw a current clamp around our Loop here because that's how this is designed and um, see what we see and then let it sit here and warm up. Perhaps one of these O2 sensors is shorting when it gets hot? Um, let me get this set up here for us and I'll kick this back out and wall join together here and see what we see that around a 10 amp scale of our graph down here.

And then we're going to put some more or less time ice cream. We'll go say 100 milliseconds. Yeah, so they are duty cycle controlled as you can see those Peak amperages little waveform being brought up there. Okay, does that make sense to you if you stick our test light on here.

Well, now if we stick our test light on, we're not going to see much other than a steady light. Yeah, so we got a steady light. A little bump in the current. so yeah, the control side.

the ground side that switches those injectors. Uh um, oops. so there it must have. So now it's changing Duty Cycles as it goes on here so you can see, put some more time on our screen here.

see how it's keeping Mo2 heaters on a little bit longer now. But the interesting thing to see is our Peak amperage is only around two amps, so that's good. And it's it's going to change. It's going to dictate how long it keeps.

Uh, you know that heater circuit on for? Okay, we got something else changing here now. Probably should be using the Pico for this. so it must be turning different O2 sensors on and off. So that's what we're seeing here in waveform.

This is 102 sensor that current that's riding on top of it. That's another O2 sensor turning on. You know the control side of it. So I'm just going to kind of monitor this and let it see.

or let's see what's happening as it's uh, you know, warming up here. Maybe one of them shorted out something, has blown the fuse. You know? one of the O2 sensors is my assumption, but we can see 102 sensors drawn at least two amps. Another one's drawn another two amps on top of that, and that's kind of what we would expect to see.

So depending on the resistance value of of each heater circuit, which most O2 heaters are around, you know, 12 ohms. So therefore, they draw around one amp 12 to 14 of them. something like that. if I don't let it sit here and run.

I'm going to pop into some OEM data while we sit here and watch this and see if we can see the individual O2 sensor. Some some manufacturers allow us to see the current draw rate in scan data, so as that's warming up, I'll look for that. I'm gonna put a little more time across the screen here. you can kind of get big picture.

Let's see what happens. It's been a few minutes every everything still looks pretty normal here. Okay I guess it's normal normal, but it could. What? I see here in scan data is kind of interesting.

So we look in scan data. Uh, AFR Sensor One Heater circuit running a duty cycle of 35 36 percent heated action. Sensor three: There's the O2 sensor, a heat auction Sensor three Bank One The heater is turned off, so that's perhaps one that we're not seeing there yet. Uh, sensor number two is on Sensor number one is on the sensor.

number three is off. Okay, well that's interesting I don't know what the strategy is to turn number three on other than talk dirty to it. but I don't even know if it likes that. So let's look in bi-directional controls here I don't see anything there.

Let's go to special functions and I don't see anything there cow Dane It would be nice if we could just turn that O2 Heater on. Well, that kind of sucks I don't know what its strategy is to turn it on I'm going to go back to live date I'm going to give it a couple rev up tune-ups I'm going to look at that O2 heater number three see if it turns on when it does. If all of a sudden you know, do we develop a problem then? So let me. uh, let me fiddle with that.

Let me look the heater. There's sensor three that there so shows. the sensor shows it being off. Now we have not even confirmed that this has three sensors, but it's setting a code for it so we can only assume that it does.

But let's uh, let's rev it up a little bit or something. I Have no idea, but that O2 sensor itself is not even functioning. it's just stuck. Oh, they're wiggled a little bit so that's all right.

It's like that O2 sensor. it's not even working I put a bunch of time on the screen just in case it quit, but you can see its strategy as far as turning O2s, you know, heaters on and off. Like right now, it's only got one turned on. Pretty interesting.

We don't see it turning on a number three and from the looks of it I really don't have a short with the two that are functioning. All right. Pretty good there. I Tell you what you know.

I Could hear some exhaust parts rattling when I pulled it in like some heat shields and stuff. Let me, um, let's get it up in the air and do a visual inspection on the number 302 sensor. Maybe there's a heat shield that fell down and traveling against it and went out. Tips: Whatever, its strategy is to turn that one on.

Maybe it shorts out. so let's get it up in the air and just have it look. Anyways, Oh, she's brand new. There's a new one I Knew we were going to find a new one.

Okay, so that's probably our eBay special and you know what? I'm wondering see how that pipe's been replaced I don't know if it's made in Japan on it all twisted up there. I'm wondering if the pipe brought it out. the wire fell down because she's all zip tied, melt, melted against the pipe, blew the fuse and here we are. today.

Somebody fixed this, but perhaps never fixed. You know, the fuse stop. So let's see if this one's shorted. We can easily check to see if this heater circuit is any good and then if it is, then we can.

Just you know, we go for a rip and see if this thing turns on instead of trying to learn its strategy. That's what I would do if it was me. Oh sorry buddy. Oh, okay, that's off.

So now we need to check the heater circuit. So it's going to be the one with the same color wires, right? right? We got a meter that reads homage we've had over there. So bright and we're expecting to see something low less than 20. Probably more than 10..

So let's see what we have I'm going on. matte wire The white wire. This guy can't see a white wire in The white wire. resistance is 5.4 Ohms.

It is duty cycle controlled so that would be okay. We should have power down here. 5.4 Ohms Let's look up a spec just to be sure that is pretty low. Let's see if we can find a spec and service data service data shines through for us.

um uh. looking at let's see uh check resistance between heater terminals filing charts two and three which I'm going to assume are the heater ones because the other one should be open. Uh, 3.4 to 4.4 Ohms to 77 degrees. So us having five or whatever it was is okay.

But then the best part is here. You know, how do we turn this thing on I saw, um where we're at? Uh. operation. Okay, so above 3 600 RPMs it's off below 3600 RPMs that flying conditions are met.

Engine warm up drive for three minutes at 50 mphs or more, keeping the steady as possible during cruising. then the heater is turned on so we actually have to go drive it. So I'm good with this. I'm going to double check to make sure that you know our terminal is two and three are indeed the heater circuits which like I say they should be.

It's usually I don't know a case any different but it's typically always the ones with the same color wise. two Grays or two blacks or two whites or two blues or two purples. Whatever. those are usually your heater circuits I'm going to verify uh, pin two and pin three.

make sure that's right. and then looking at our Clues I'm thinking somebody just did a complete the job when they did this repair. Gotta make sure it's safe enough going through it. Yeah, it's safe enough.

Let's go clear the codes. Um I've got our O2 sensor up here or you know on that fuse still looks like there's only one on right now and that's true. So there's only the front O2 sensor is turned on right now at 37 duty cycle. Uh Bank two is off Bank three is off.

So we're gonna go drive it and try to meet the criteria that was in service data and just see what happens. See what our current draw looks like? Once we get that rear O2 sensor turned on, it seems to be the only way to turn it on without. you know, turning it on herself. Manually jump in the wires stuff like that.

So let's go for a little rep. Sounds like we got to drive for at least three minutes steady. So I'll go do that and we'll see what happens I Find it very interesting that it doesn't turn that heater circuit on until after the car's been driven and warmed up and stuff. So that's I don't know what its strategy is.

Our second O2 sensor just turned on I Know you guys probably can't see it. Um, but it's pretty interesting. Good cruising, steady and I see the rear or that number 302 sensor. so that's the second graph down.

Starting to work, the O2 sensor starting to come alive. heater is still not turned on, but we haven't met the criteria yet. but it appears that that O2 sensor is working signal lines anyway. So let's let's you guys can't see it.

Let me pull over. I Just saw a change in this. Oh yeah, so our O2 heater is on. All right? Well, let's pull over.

We're still below two amps of current. I'm gonna swing in here all right. The oh so number three is on, number two is on. you guys can see it hopefully and look at that.

So we're below two amps, it's not shorted, and all the O2 heaters are on. Our front's running at 26 percent, our rear is on, number two is on, and number three is on and then we can see here. Hopefully you guys can see something other than me just holding the camera that our value is around 2 amps. That's fantastic.

So perfect. We fixed it. Well, we didn't fix it I Guess we kind of fixed it. We put the fuse in it, we finished fixing it.

How's that sound? I'ma head back to the shop. back at the shop. everything looks good there. Look at it here.

So just on that little short test drive, look at that. We've got all the monitors to run except for one, so that's good. It's probably uh, Evap that hasn't run yet. We literally went like five miles, not even went up to where we usually turn around and came back.

So let's look at readiness monitors. We're probably going to see that the EVAP is not ready yet. That's true, so Evap is not ready. O2 O2 Heater EGR Catalysts comprehensive misfire Fuel systems are all done, so that's good.

There should be no pending codes unless it's a pending code for an EVAP problem. and we have no codes. So what was the fix on this one? Well, I Can tell you. let's unplug our plugger down here.

We don't want to forget that the fix on this one folks was a balloon fuse. The fix for this one folks. let's simply replacing the fuse. We could have replaced the fuse, give it back to the customer and said you know, sign our let me know if it blows again.

But we have definitive data now that we actually fixed it for real because we can see the current draw on that circuit with everything that's on that circuit being turned on, which was all 302 sensors. So thankful for service data that explained to us how to get number three to turn on, which was drive it for three minutes over 50 after a warm-up cycle. And it was exactly that. After about three minutes of driving, all of a sudden I seen the current change on a scan tool I looked down and boom, it's turned down and then we were able to pull over and you could see that we're well within the limits of that circuit design.

You know we're at two amps roughly, and we can only assume that at some point there was a repair down there because so two centers knew we saw that the pipe is new and then zip tie. that's pretty new. so chances are the wire was down there, melted and well, you know the rest of the story. Tell me the rest of your story down in that comment section.

Questions, comments, Concern: The Entity the Facebook not The Tick Tock And just for my viewers, if I can do it, you can do it. Thanks for watching Foreign.

97 thoughts on “Sometimes it really is just a fuse”
  1. Avataaar/Circle Created with python_avatars Zeren Pham says:

    Hey Eric, for this job did you bill the labor based on the actual time you put into the job or did you only charge them a basic diagnostic fee (plus the fuse) since the fix was straightforward and didn’t involve harness repair or replacing other parts?

  2. Avataaar/Circle Created with python_avatars Stumpy's Transportation says:

    SMA Technical college, class is now in session. Another great video Eric! Thanks for all you do.

  3. Avataaar/Circle Created with python_avatars imacgst27 says:

    Great diagnosis as always Mr O. It amazes me how many people drive around with that much trash in their car. Thank you for taking the time to bring us along!

  4. Avataaar/Circle Created with python_avatars Bruce Evennett says:

    If you had a reading of 5 ohms on number 3 o2 sensor then with 3 sensors running we should see 6 amps but we were only seeing 2 amps. guess I’ll have to watch it again

  5. Avataaar/Circle Created with python_avatars Sarge Freedom says:

    Fuse bad, good on ya to do a little more to make sure and show the customer you go the extra steps. I ALWAYS hated a call back, most of my stuff was 100 miles and two hours one way…. Doesn’t taste good when you have to eat that

  6. Avataaar/Circle Created with python_avatars Larry Fry says:

    Well done, my man. Well done.

  7. Avataaar/Circle Created with python_avatars Stanley Knight says:

    Earlier you said, if I understood correctly, your shop hours were $90.00 per hour. My mechanics hours were the same 2 years ago. MY most resent repair he said that his labor hours were now $125.00 per hour. We live around the Atlanta area. Maybe your hours are a little low, especially in the PRNY. 😅

  8. Avataaar/Circle Created with python_avatars Brad D says:

    Same car I put a engine in had it blow 2 coils back to back still to this day don’t know why I chalk it up to a cheap parts failure I searched that thing up and down and could never find a problem it’s been fine since.

  9. Avataaar/Circle Created with python_avatars Brad D says:

    Just put a engine in one not too long ago wasn’t a bad job thought the “ fuse box” was a little over engineered but what do I know I just fix the damn things

  10. Avataaar/Circle Created with python_avatars BigOwlBrain says:

    If it's of any condolence, your welds looks better.

  11. Avataaar/Circle Created with python_avatars donald hoss says:

    Thank you for taking the time to explain your diagnosis when you do your videos👍

  12. Avataaar/Circle Created with python_avatars john auerbach says:

    Taking time understand the system of interest, applying logical thought process will solve the problem. Easier said than actually accomplished. Eric , you are the best I have seen at this! Kudos.

  13. Avataaar/Circle Created with python_avatars george martin says:

    I worked in the electronic field maintaining high dollar I&C equipment, and fuses were considered "wear items" requiring replacement at specific intervals.

  14. Avataaar/Circle Created with python_avatars Frank Thomas says:

    I just recently had a 2016 Mazda 3 purchased from auction. It was in limp mode, trans wouldn`t shift. When i tried to pull codes I had no com with TCM. First thing I went for was the fuse box. I found the TCM fuse missing. I replaced the fuse, everything was back to normal. Sold the vehicle and no problems with it.

  15. Avataaar/Circle Created with python_avatars Ap47 says:

    Eric just curious you use a test light over a power probe tool just wondering the reason? Does it give more of a load on circuit then a power probe or your just have it and like it? Thanks

  16. Avataaar/Circle Created with python_avatars Duke Allen says:

    No, never is it just a fuse. Something blew it. Full stop.

  17. Avataaar/Circle Created with python_avatars phil merrifield says:

    Nissan calls it the intelligent power distribution module, I call it the idiotic power distribution module or the idiotic potential for spending dumb money

  18. Avataaar/Circle Created with python_avatars Steve A says:

    Resistance is futile! Fuses do have a finite life. Rust is terminal though!

  19. Avataaar/Circle Created with python_avatars Jaakko Fagerlund says:

    Where do you pull those schematics and service data from? Looks very well organised and very compherensive.

  20. Avataaar/Circle Created with python_avatars Hola! Steady Eddie says:

    So…… How did you approach this customer with a bill for (I would guess) one hour labor and tell them you replaced a fuse? I totally get it, but I can see a customer whining about paying $100 plus and saying you "just" replaced a fuse. Do you ever explain that it took X amount of dollars in test equipment, and X amount of online service data, both of which require yearly fees to maintain? How much would you say you spend in 1 year just to maintain online service data access?

  21. Avataaar/Circle Created with python_avatars BUTTABALLA999 says:

    Couldn't you have at least TRIED to talk dirty to the third O2 sensor to see if it would get turned on?

  22. Avataaar/Circle Created with python_avatars nomad57 says:

    a shop right now has my 99 s-10 4×4 v6 4.3 truck says they cant diagnose=find the problem with it losing power…just wondering how many days has your longest diagnosis took on a car/truck…

  23. Avataaar/Circle Created with python_avatars C Quay says:

    I watched this then rewatched a video from about 8 months ago regarding a Toyota truck and a pin fitment issue. Mr. O. Your speech has drastically improved over the course of your orthodontic ordeal. Way to go!

  24. Avataaar/Circle Created with python_avatars Ken Walker says:

    Dang, was that date on the battery correct? It was from 2015. That thing is over 8 years old and still good? never would happen in Florida. We get 3 to 4 years at best on our batteries.

  25. Avataaar/Circle Created with python_avatars shirmworm says:

    Mr. Goodguy!!!! Doin the good stuff!!!

  26. Avataaar/Circle Created with python_avatars Unwoke Patriot says:

    Did you wear a baseball cap to your wedding

  27. Avataaar/Circle Created with python_avatars Mike Abbitt says:

    Dr. O. going the extra mile to make sure that the job is done right. 👍

  28. Avataaar/Circle Created with python_avatars Foodskewed919 says:

    I wish more shop owners/service writers would watch your videos. It’s frustrating to explain things like simply a blown fuse to someone expecting more.
    The worst a check engine light that was on but now isn’t. Try explaining “it isn’t broken right now” to a service writer. 😂😂

  29. Avataaar/Circle Created with python_avatars Giggitygoo says:

    I had an interstate from Costco that lasted 8 years. The downside to keeping it that long was that it went with no warning. It cranked fine one day, then left me looking for a jump 100 miles from home the next day.

  30. Avataaar/Circle Created with python_avatars NavyGirlO6 says:

    “…other than talk dirty to it, but I don’t even know if it likes that!” Eric O., you are a brilliant mechanic, and we all greatly appreciate you sharing your experience so generously. The injection of humor is serious icing on the cake. Thanks a million for you being you!

  31. Avataaar/Circle Created with python_avatars Fedwrench says:

    You're one in a million. You always go the extra distance to determine the root cause and correct it. those peeps back there in the People's Republic of New York don't realize how lucky they are to have you. Thanks for sharing!!!

  32. Avataaar/Circle Created with python_avatars Rusty says:

    Tell Mrs.O that my son is a C-tech at Firestone and his shop rate is $150/hr.

  33. Avataaar/Circle Created with python_avatars Mike Man says:

    So your on the side of the road in the pouring rain and you need to check to see if you blew a fuse. Of course you always carry your push pin tool. Stupid engineers

  34. Avataaar/Circle Created with python_avatars Ken Elsbernd says:


  35. Avataaar/Circle Created with python_avatars Jay Gold says:

    Drive cycle is very important for everything to reset itself.

  36. Avataaar/Circle Created with python_avatars MRrwmac says:

    Nice catch. Easy fix if you have the experience like Eric does to know what to look for AND how to confirm!!!

  37. Avataaar/Circle Created with python_avatars Jay Gold says:

    Bobs your uncle little fella.

  38. Avataaar/Circle Created with python_avatars Kyle Tuttle says:

    Great fix Eric.

  39. Avataaar/Circle Created with python_avatars Frank D. Brennan says:

    That was excellent. I wonder if you asked the customer about it? I'm sure he probably paid out some serious money already and a few other mechanics

  40. Avataaar/Circle Created with python_avatars The Devil In The Circuit says:

    Anything–electronic or mechanical–will act as a fuse if you use it wrong enough.

  41. Avataaar/Circle Created with python_avatars Billy Lane says:

    Why don't people clean their cars when they take them to a shop? What if someone has to get in that floorboard?

  42. Avataaar/Circle Created with python_avatars Dukw Driver says:

    Systematic analysis of the dog's breakfast left by cousin pookie. I believe that to be the correct American saying.
    Pick hammer findings scared me to drive it though.
    Such a dry sense of humour when you don't try. "No current draw currently"…LMAO

  43. Avataaar/Circle Created with python_avatars Clint R says:

    My question is why the 15amp fuse for such a low Amp draw circuit?

  44. Avataaar/Circle Created with python_avatars Latarian HoodRat says: