2004 Jeep Cherokee P1391 Cam/Crank Sensor Code -Pt 1

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  • เผยแพร่เมื่อ 7 ก.ย. 2024
  • This time I am diagnosing a 2004 Jeep Grand Cherokee with a Cam/Crank code with misfires and hard start.
    I'm not very familiar with Cam/Crank sensors so you get to watch me struggle with this one!!
    Part 2 is here: • 2004 Jeep Cherokee P13...
    Here is link to my friend Eric O's channel- / @southmainauto

ความคิดเห็น • 173

  • @acetech9237
    @acetech9237 9 ปีที่แล้ว +2

    Matt I know you already know this, but you can't worry about the people who don't like you talking about the mis-diagnosis. Frankly, I will admit I have had a brilliant technician like yourself, critique my diagnosis of a job on a few occasions, coming up as a flat rate tech, but I always take it as constructive criticism. Truthfully, when it comes to cars, "I HATE" when I have overlooked something or made the wrong assessment, truly everyone has had a mis-diag. at some time in their career, it's called learning, but I have progressed in the last 13 years significantly, I'm even more happy what you have taught me in just 30 days as a subscriber. It's one thing to not know, and learn from it. It's another to be told what was right, and ignore it. Screw all the little baby's who complained, it's probably because they are a "parts-changer ".
    '

    • @SchrodingersBox
      @SchrodingersBox  9 ปีที่แล้ว +1

      +Adam Czajka Agreed!! Thank for the support bro

  • @DJDevon3
    @DJDevon3 9 ปีที่แล้ว +4

    Sometimes the CKP is inside the bellhousing and goes off of the flexplate/flywheel. Don't get it confused with a speed sensor or turbine speed sensor. There are plenty of things that get plugged into a transmission. That datasheet you have says it should switch between 0v and 5v which it does and looks like a beautifully perfect signal to me. Since it doesn't have a 1-2-3-3-2-1-3-1 pattern it's not the 4.7L engine. Having the same kind of spec data for the CKP sensor is just as important. Looking forward to Part 2. You learn, we learn. Great video as always.

  • @mrghiax
    @mrghiax 9 ปีที่แล้ว

    It's incredible the amount of professionals that replace the component and then replace the computer without even checking the wiring between the two! It's crazy and costs people hundreds of pounds they never needed to spend.

    • @SchrodingersBox
      @SchrodingersBox  9 ปีที่แล้ว

      +mrghiax J see it almost every single weekend. It's just amazing. All kinds of other tactics- like replacing entire systems instead of diagnosing components. I recently diagnosed a bad solenoid for a secondary AIR. but a shop quoted them $1800 for an entire system- pump, solenoid, check valves and all. Man- not only do you not need to diagnose a system in that case- you don't even have to know what it's purpose is!!!!

  • @jwciiigenerationtruckingll1009
    @jwciiigenerationtruckingll1009 7 ปีที่แล้ว

    Mr Matt, I've been watching your videos for a while now. As for the comment you made ( people NOT liking you when throw other shops with mis-diagnoses, but still profit off of their mis-diagnoses) these are the ones who don't need to be a mechanic. I too am just like you.......fed up with shops and wanna be mechanics who take advantage of people and their hard earn money. I know that I am dying to close a couple of places down in my home town, because of mis-diagnoses and I am doing just like you. If I mis-diagnois a part, then my customer DOES NOT PAY FOR THAT PART!!!! Keep up the good work and please tell me how to subscribe to your pay channel. May the Lord bless you

  • @nijoel
    @nijoel 9 ปีที่แล้ว

    Back in the early 90s, there was a public access show called "FUST" in my area which was about a small shop repairing cars that others couldn't. I don't know him personally, but he was a brilliant car guy, retired years ago. He'll start off saying here is the problem, here is what was done by the shop, yet same problem persist. Only he went one step further than you and would say which shop did the shoddy work. A portion of the show was a rant with not so kind words, but kindly stating how anyone can live with themselves ripping off people. There were no repercussion however, because there were very few viewers and it only lasted about 5-6 shows. I can imagine what would happen if he made videos in this day and age.

    • @SchrodingersBox
      @SchrodingersBox  9 ปีที่แล้ว

      +nijoel Yeah trust me I would love to "call out" these shops but i am not sure the legal repercussions... Or other potential retaliations!

  • @lukecartwright1803
    @lukecartwright1803 8 ปีที่แล้ว +7

    i love when u list mis diag by shops

  • @chungaleta1234
    @chungaleta1234 9 ปีที่แล้ว

    my s10 truck has exactly the same problem........ I cant wait for that 2nd part.

  • @logicus_mentis
    @logicus_mentis 9 ปีที่แล้ว

    Haha. I can't believe I have to wait for an answer! If the workshop just threw parts at it, I wonder if they used crappy parts or didn't install correctly? Can't wait for the outcome! Thanks Matt.

    • @SchrodingersBox
      @SchrodingersBox  9 ปีที่แล้ว +1

      +Mathew Wood Exactly- I need to re check their work- installing the cam sensor wrong would put it out of sync with the crank

  • @siucbset
    @siucbset 9 ปีที่แล้ว +2

    Wow! You are connected to Eric O@SoutMainAuto. I like his channel because he makes informative and well presented videos.

    • @SchrodingersBox
      @SchrodingersBox  9 ปีที่แล้ว +1

      +siucbset Yeah I ran into him a few months ago by accident when I saw his comment on another channel and it was clear he "gets it". I clicked on his name out of curiosity and found he had a channel. I thought it was awesome and he deserves the promotion.

  • @gouveiaclassicos
    @gouveiaclassicos 9 ปีที่แล้ว +1

    this is a mechanics diseases call laziness syndrome all over the world, over here in Portugal is just the same I am like you never change parts in till I am shore were is the problem very good keep on whit the videos

  • @prasanthmoolethodi3152
    @prasanthmoolethodi3152 5 ปีที่แล้ว +1

    Studied a lot of things. Thanks prince

  • @jamesmiller3297
    @jamesmiller3297 9 ปีที่แล้ว

    Guided component tests on that VantagePro well help with scope hook up connections.

  • @trainer2018
    @trainer2018 9 ปีที่แล้ว

    Matt did you try your record feature on the vantage? You can use record and a single shot trigger I believe on a falling slope so when your signal drops out it will draw the pattern across the screen and record it. This comes in handy on intermittents, just have to make sure you are on the right signal,lol. You could do cam and Crank at the same time with this setup. Look in your book and it should show you how to do the single Shot trigger.

  • @billyr9840
    @billyr9840 9 ปีที่แล้ว +1

    Matt, If you did not erase the P1391codes, you could have looked at the freeze frame data PIDs to see if you had a rpm signal along with your misfire counters when the DTC first set which would of pointed you in the direction of the crank sensor. You need to scope that crank sensor to see if you have a crank signal or if it is dropping out, especially when it is misfiring.. Also you said the other garage put a new cam sensor in and a ECM. It was hard to see, but it also looked like they put a new crank sensor in. Maybe it was not installed in far enough or close enough to the tone ring. If it is a intermittent problem maybe they used an after market sensor other then Chrysler/Mopar that is causing all kinds of problems including your misfires.

    • @SchrodingersBox
      @SchrodingersBox  9 ปีที่แล้ว

      +Billy R Great idea man, I did not think to look at RPM!! All your thinking dead on... I did get it fixed as you will see in Part 2. Our thinking is identical lol!

    • @billyr9840
      @billyr9840 9 ปีที่แล้ว +1

      Matt, Not quite, I still think a oxygen sensor is a oxygen sensor bro! LOL!BTW, if you pull that crank sensor out and the paper spacer is still on it, it is installed incorrectly or it is an inferior product! I'm glad to hear you came back to us ( 2 persenters ), applied some common sense and fixed the car. Can't wait to see part 2, but it was fun to see ya struggle! LOL! Hey that's how we all learn! I suspect that this vid series is going to be another great learning experience and fix for everyone! Keep e'm coming!

  • @KingKatRider
    @KingKatRider 5 ปีที่แล้ว +1

    yes luvin it cuz chasing the same on a 00 chero and done everything just like you

  • @scraiga66
    @scraiga66 9 ปีที่แล้ว

    When you hooked up the scanner I thought for sure that you would look at the cam sync and crank sync pids.

    • @SchrodingersBox
      @SchrodingersBox  9 ปีที่แล้ว

      +Steve A I wanted to but there weren't any available!

  • @martinsmith2903
    @martinsmith2903 9 ปีที่แล้ว +1

    Maybe the PCM initially uses the cam sensor to verify which stroke the crank is on ie cyl 1 TDC compression, from then it can use the crank pulses to time everything, so unplugging didn't stop the engine? Its obvious the crank rotates twice to each cam rotation so you need to know which one of the two rotations its on, if that makes sense!

    • @billyr9840
      @billyr9840 9 ปีที่แล้ว

      Spot on! but I do believe that the PCM uses Crank/Cam sensors for more than just telling what stroke the engine is at. I believe it's main purpose of using both the Crank/Cam sensors is to determine if the Crank/Cam shafts are where they are suppose to be at any given time, in relation to one another, known as mechanical timed. If the PCM knows by using the Crank sensor signal, at what degree of rotation the Crank shaft is at it also knows what piston is at TDC compression stroke as you stated, and can fire that coil for that cylinder. Using the Cam sensor signal to tell what degree of rotation the Cam shaft/shafts are at and how many rotations in relation to the Crank shaft it can also tell when any given cylinders intake valves are open/opening so it can open that cylinders injectors at the precise time and length needed. I also believe that in the case of a Cam sensor failure the PCM can calculate which cylinder's intake valves are open for injector timing and when that cylinder is at compression stroke for that cylinders coil firing timing, using the Crank sensor alone. By knowing the degree of rotation of the crank shaft it can work out which cylinder is at any given stroke or TDC, ignition timing and the degree of rotation of the Cam shaft/shafts for injector timing. The only draw back to this strategy is the PCM has no way of knowing when the Crank shaft and Cam shafts are no longer in time/sync with each other, such as in the case of a timing chain/belt has jumped a tooth. With the Crank or the Cam sensor dropping out the PCM threw that P1391 code because of the lost ability to tell if the Crank and Cam are in sync with each other. With the PCMs ability to do this with only a Crank signal is the reason the engine did not die when the Cam sensor was unplugged! If that Crank sensor completely lost it's signal not intermittently as in Matt's case, the engine would die because the PCM uses the Crank sensor for direct input for ignition coil timing!

    • @SchrodingersBox
      @SchrodingersBox  9 ปีที่แล้ว

      +Billy R Billy's description is exactly what my understanding is of their function. Well described!!

    • @martinsmith2903
      @martinsmith2903 9 ปีที่แล้ว +1

      +Billy R Yeah agree, its interesting stuff and I am sure Matt will do a follow up learning vid. In the old carburetor days and wasted spark you only needed crank reference to time the spark as companion cylinders would fire at the same time. With the PCM fuel injected systems its spark and fuel injector timing that is required, the fuel injector timing definitely needs to know which stroke cycle the crank is on. I am sure there are many different systems and ways of achieving this timing of the spark and fuel so system identification is an important first step IMO.

    • @billyr9840
      @billyr9840 9 ปีที่แล้ว

      Schrodingers Box Matt, I was hoping you would see that post because I believe that answers your question of why the car did not die when you unplugged the Cam sensor.
      Also I was wondering after you cleared the codes did it real set the same code when you unplugged the Cam sensor?
      Matt, this kind of stuff is great! Really keeps your attention, hey!

    • @SchrodingersBox
      @SchrodingersBox  9 ปีที่แล้ว

      Martin Smith Absolutely true- thats where my biggest challenge is in fact- different systems. I was sure that on all cars (and for sure most every one I have seen) if you unplug a cam sensor the engine will die. But obviously, others like this one have no effect which caused me to think the PCM was not using the cam sensor signal maybe due to the DTC.
      this totally led me on the wrong path. I guess I have to research every vehicle if I am to use that strategy

  • @johnlindsey9915
    @johnlindsey9915 9 ปีที่แล้ว

    I haven't watched Part 2 yet because I don't want to spoil the surprise, but having owned a 1997 Grand Cherokee since 2005, I have been through the Jeep stall/ crank-no-start phenomenon. My understanding is if the vehicle cranks for 5 seconds without starting, the ECU cuts the fuel signal, so that might explain the loss of fuel signal when it doesn't start quickly. You might have a bad crank sensor but I wouldn't discount a bad-right-out-of-the-box fuel pump. Ask me how I know.

    • @SchrodingersBox
      @SchrodingersBox  9 ปีที่แล้ว

      +John Lindsey Why would you suspect a bad fuel pump with neutral LTFT's and no STFT adjustment?

    • @johnlindsey9915
      @johnlindsey9915 9 ปีที่แล้ว

      +Schrodingers Box Based on the STFT and LTFT I wouldn't, but my experience with bad out of the box parts would have had me checking the fuel pump pressure first. To be honest though, if I didn't know the fuel pump in that Jeep had been replaced, I would not have even suspected it.

    • @SchrodingersBox
      @SchrodingersBox  9 ปีที่แล้ว

      John Lindsey But the cam sensor was just replaced a day before- the fuel pump 5 months before.... why fuel pump first and not crank sensor which was literally "right out of the box"???

    • @johnlindsey9915
      @johnlindsey9915 9 ปีที่แล้ว

      +Schrodingers Box Hi Matt, the cam sensor waveform was good. You didn't show the crank sensor being flaky until part 2 but I did mention possible crank sensor issue in my first comment. Checking the fuel pump would be based solely on my experience with bad parts. Unscientific, yes, but it only takes a few minutes to check fuel pressure. The joke in our house is, if the parts store has 10 in stock and one of them is bad, it will have my name on it.

  • @gouveiaclassicos
    @gouveiaclassicos 9 ปีที่แล้ว +1

    normally on this earlier jeeps the cam sensor is there for fuel economy look at the signal and converting the injection on to secuencial

  • @SteveRobReviews
    @SteveRobReviews 9 ปีที่แล้ว +1

    Interesting stuff Matt. Looks like your going to retrace all the work or unwork that's been done and verify its the correct parts and installed correctly. As Billy stated the RPM data pid on the no start would have helped but it seems not always , lots of variables . Hum- loss of signal on cam or crank , wish Chrysler didn't display codes that look like a wild guess just like the shop that guessed at all them parts. I like it when you provide the previous work details , good or bad. Part 2 ,can't wait .

  • @mtrltoolman
    @mtrltoolman 9 ปีที่แล้ว

    This is crazy case i hate this situations but it's great to learn.
    thanks for sharing this video.

    • @SchrodingersBox
      @SchrodingersBox  9 ปีที่แล้ว +1

      +toolman talal Exactly bro- these situations ARE how you learn! At least it's how I learned everything I know.

  • @jamesdewer
    @jamesdewer 3 ปีที่แล้ว

    Had my 4.7 changed and the wiring looks like it has every bit of 232,000miles. Cracked, oil sodden bare at the connector. I'm using orange oil and sanitizing the wiring.

  • @labodiesel7443
    @labodiesel7443 8 หลายเดือนก่อน +1

    Hi, it's Yves from québec city, i'm asking a question to my self, when you do a sherch for information or data, wy dont you use a toolt like AllData ?

    • @SchrodingersBox
      @SchrodingersBox  8 หลายเดือนก่อน +1

      Often I do however if I can fine the information for free it’s always better!!

  • @markgabello58
    @markgabello58 2 ปีที่แล้ว

    I have an 01 Jeep Grand Cherokee with a 6 cylinder I got a code 340 going to watch your video

  • @ForkliftJoe
    @ForkliftJoe 9 ปีที่แล้ว

    I had a 1995 Jeep with the 4.0 inline six about 10 years ago, crank sensor was bad, the sensor inside the distributor was broken in half and the ECM/PCM was fried with charred diodes and resistors falling out of it. Kind of an expensive no-brainer... The PCM was a dealer item and was $500 bucks.

  • @albshr13
    @albshr13 3 ปีที่แล้ว +1

    You're the man bro!

  • @mhn3773
    @mhn3773 9 ปีที่แล้ว

    I know you said cam sensor trouble code but I was waiting for you to say they changed their O2 sensors. =-)

    • @SchrodingersBox
      @SchrodingersBox  9 ปีที่แล้ว

      +mhn3773 No they already did that the first time they saw the truck just before I did the fuel pump diagnosis on the last video.

    • @mhn3773
      @mhn3773 9 ปีที่แล้ว

      having watched quite a few of your videos, that does not suprise me. its a shame. I am glad they can eventually get it sorted out with you.

  • @michaelherbert8213
    @michaelherbert8213 9 ปีที่แล้ว

    Come on man!!!!!! I can't wait for the next part to watch you whip out your oscilloscope and back probe things. lol.

    • @SchrodingersBox
      @SchrodingersBox  9 ปีที่แล้ว +1

      +Michael Herbert I feel ya bro.... believe me I try to whip it out and probe as much as possible, but I was too busy using an oscilloscope for this video.

    • @hddm3
      @hddm3 9 ปีที่แล้ว

      +Schrodingers Box hahahahahahah

  • @williamnagel2654
    @williamnagel2654 5 ปีที่แล้ว

    It started up at 7:43 yes, so you had spark before the spark tester.

  • @m2003h
    @m2003h 6 ปีที่แล้ว +1

    Thank you for letting us know

  • @ozzstars_cars
    @ozzstars_cars 9 ปีที่แล้ว

    Cheese and crackers that CKP is the root of all evil!?? Amazing how lazy the 'pro' was that worked on this car not to do a REAL diagnosis.....damn 98%er! I know it takes a lot of time to edit the footage and I appreciate what you do man. Enjoy the holiday

  • @TheRubenTrance
    @TheRubenTrance 7 ปีที่แล้ว

    Hello, Thank you so much for sharing this video... I was wondering if you may shed some light on the problem I have with my 03 Jeep Grand Cherokee 4.0. Initially my car stalled pulling into my garage. Engine was cranking but no start, and gave P0320 on my dash which pointed to the crank sensor. So did replaced my crank sensor with a BWD brand. Engine started & ran but was misfiring and gave another code P0340. which pointed to the Cam sensor this time, & so I went ahead & replaced the cam sensor as well with Mopar OEM. After that still engine misfires/ shakes then gave a different code again P0352 which pointed to Ignition B , so I went ahead & replaced the Ignition coil pack with Delphi brand (close to OEM) . After that replacement, engine ran well & so I took a it for a test drive but after about 15 miles the engine starts to misfire again then eventually stalled on the side of the road. "Checked engine" light was on & this time its P1391 which points to crank/cam intermittent lose. Car had to be towed back home as it wouldn't go anymore. After a good few hours parked at home the car started & ran like normal but eventually misfires yet again when warmed up giving the same problem code P1391. Anyhow, I am quite perplexed by now as you may imagine... I would be grateful to hear your opinion on this matter, if able . Other mechanics on You Tube seem to suggest that the crank sensor must be replaced with OEM Mopar. Do you supposed this is true , & absolutely necessary to do for this particular issue? Thank you so much! Reuben PS. Do these (newly replaced) sensors need reprogramming with car's PCM?
    Show less

    • @SchrodingersBox
      @SchrodingersBox  7 ปีที่แล้ว

      What data do you have? WHat is the feed signal voltage. Is there ground indetrgrity? Was voltage measured at the hall effect or PCM? What was the data that indicated the ignition was faulty? Was there feed to the coil?
      You bhave not You have no data that I can use.
      I need some information to help define the cause.

  • @kimbrown591
    @kimbrown591 2 ปีที่แล้ว

    That's why I do my own research and work on my own vehicle

  • @cory6330
    @cory6330 9 ปีที่แล้ว +1

    Whoo hoo! Ornaments! Good video p!

    • @SchrodingersBox
      @SchrodingersBox  9 ปีที่แล้ว +2

      +Corynne Jones Thanks B! But no one will know what the hell we are talking about!!

    • @SchrodingersBox
      @SchrodingersBox  9 ปีที่แล้ว +1

      Jason Curry Lol... that's my g/f- the car in the video belongs to one of her employees and she convinced him to bring it to me. Her hobby is painting ceramic christmas ornaments and so she wants me to buy her some ornaments since she helped with the video lol.
      Couldn't make this stuff up bro.

  • @mayoman8565
    @mayoman8565 3 ปีที่แล้ว

    tap the cam sensor it should fire right up. mine did so I replaced cam sensor. so far so good

    • @SchrodingersBox
      @SchrodingersBox  3 ปีที่แล้ว

      how do you determine it was bad cam sensor vs bad wiring though? tapping on it could simply have jostled wiring that was shorted to ground.

    • @mayoman8565
      @mayoman8565 3 ปีที่แล้ว

      because i did not wiggle the wires just tapped the sensor@@SchrodingersBox

  • @DENicholsAutoBravado
    @DENicholsAutoBravado 9 ปีที่แล้ว

    At 9:21 when you're hypothesis for testing met an unpredicted result, it just got interesting. Sorry, I know, you didn't have time for that, but it's just like my old saying goes from assisting in surgery, "As soon as it's interesting for the [Surgical Tech], the surgeon is sweating bullets." I'd say me instead of Surgical Tech, trying to be obvious.

    • @DENicholsAutoBravado
      @DENicholsAutoBravado 9 ปีที่แล้ว

      I get back to thinking at the beginning with the timing advance of -50, that was a major hint to me. Sure, I haven't watched timing advance on a lot of cars, but that's a lot! Timing belt or chain skip some and the engine is correcting super far, but sometimes gets it wrong? Best guess within a minute of my last comment.

  • @happy543210
    @happy543210 9 ปีที่แล้ว +2

    if there is spark and injector pulse, check for fuel pressure.

    • @SchrodingersBox
      @SchrodingersBox  9 ปีที่แล้ว

      +happy543210 Yes but why would there be a cam/crank code?

    • @happy543210
      @happy543210 9 ปีที่แล้ว

      Schrodingers Box
      because it's a jeep and their ecm codes are totally unreliable.

    • @SchrodingersBox
      @SchrodingersBox  9 ปีที่แล้ว +1

      happy543210 So on a jeep codes don't matter, you're saying?

    • @happy543210
      @happy543210 9 ปีที่แล้ว +1

      Schrodingers Box
      that's right. you said it yourself...spark and injector pulse should start an engine. but the engine won't start. what's missing? fuel.

    • @SchrodingersBox
      @SchrodingersBox  9 ปีที่แล้ว

      +happy543210 Quite right on that!! But if fuel pressure problem why the normal LTFT in the freeze frame?

  • @rr6542
    @rr6542 ปีที่แล้ว

    04 jeep stars up fine drive around for an hour shut it off have to wait two or three hours before it stars back up that's all the time now any ideas

    • @SchrodingersBox
      @SchrodingersBox  ปีที่แล้ว

      What data do you have? what did you determine is the FASTEC reason it won’t start?

  • @anfonieb7434
    @anfonieb7434 7 ปีที่แล้ว +1

    this is exactly what going on with mine. Thank u so much for the video. where are you located?

    • @SchrodingersBox
      @SchrodingersBox  7 ปีที่แล้ว

      Now you can diagnose it then. Thousands of causes can cause the same symptoms. What data do you have indicating the fix would be same for your Jeep? what is your fuel trim curve reading?

  • @ad356
    @ad356 9 ปีที่แล้ว

    $1,100 to replace the PCM and a cam sensor, that's absurd. reminds me once of a 1989 camaro i had. the car had the L03 305 TBI and every time the cooling fan kicked on the car ran bad really bad. that was the only time it acted up. i told them to do an electrical diagnosis and i told them the exact symptoms. they proceeded to adjust the timing on the distributor. i got the car back and it ran worse and still had the same problem. it also had a check engine light lit which was a result of them retarding the timing. they charged me $300 to make my car run worse then when i dropped it off. good grief. that was the LAST time i took a car to the shop. i work too hard to give my money away on bullshit non-fixes. i have learned not to trust them, i really do not even trust them to change my oil, especially changing my oil. i get my oil from a sealed bottle and i know what's going into the engine and i know that the drain plug is tight and filter is new and installed properly. DO NOT TRUST anyone but yourself to do the job right and reasonably priced

  • @gregoriotorres2053
    @gregoriotorres2053 4 ปีที่แล้ว

    Amigo necesito tu ayuda, instale el sensor ckp en mi grand cherokee 2000 4.0 y ahora hace explosiónes tanto en la admision como el escape, ¿que sera ?

  • @coltwister
    @coltwister 9 ปีที่แล้ว

    noooo!! for the love of god where is part two?...we need it pronto!!!

    • @SchrodingersBox
      @SchrodingersBox  9 ปีที่แล้ว

      +Nestor Maya Lol- still editing it. It will be up by end of day

  • @rhkips
    @rhkips 9 ปีที่แล้ว +2

    If you're unfamiliar with cam/crank sensors, here's everything you need to know in a nutshell:
    Look for a thing with 2-3 wires that isn't a thing that you're not looking for. If it's 3 wires, attach your DVOM to the two wires that aren't the wire you don't want to attach to. Start the engine (if it won't start, replace the catalytic converter and try again). use the DVOM to measure the engine fairies. If the fairies are sparkly, it's an analog sensor. If the fairies are flashy, it's a digital sensor. Go to eBay and find a half-price counterfeit sensor, install it, give the car back to the customer, and promptly move to a different house and change your number so they can't complain. :D
    Sorry; had to... ;)

    • @billyr9840
      @billyr9840 9 ปีที่แล้ว

      +rhkips And don't forget to install that $1,000 plus PCM and buy yourself a bottle of champagne to celebrate your fix with all those profits that you just screwed your customer with the ( deer in the headlights ) look on his/her face, out of! LOL!

    • @StationGarageSt
      @StationGarageSt 9 ปีที่แล้ว +1

      +rhkips v funny but sadly true!

  • @haidermnati5655
    @haidermnati5655 5 ปีที่แล้ว +1

    Can you help me with my 1999 Jeep Cherokee?

  • @murrmann7234
    @murrmann7234 8 ปีที่แล้ว

    Hello Sir. What meter do you use to read wave form in this video. Thank You Sir.

  • @bammbamm12
    @bammbamm12 8 ปีที่แล้ว +1

    My 2004 Jeep Cherokee engine will just shut down (off) anywhere, anytime - no warning - nothing jumpy - just like someone pulled out the plug. If I wait a minute I can start it back up and drive away. Have no idea what it is.

    • @SchrodingersBox
      @SchrodingersBox  8 ปีที่แล้ว

      +bammbamm12 Me neither.

    • @logancurry3835
      @logancurry3835 8 ปีที่แล้ว +1

      my jeep does the same thing i'll wait a few mins then it will start back

    • @bammbamm12
      @bammbamm12 8 ปีที่แล้ว

      Logan Curry
      - If it's any help, it was the crankshaft position sensor- cost about $!00 or so to have a new one installed.

    • @nathanwood3679
      @nathanwood3679 6 ปีที่แล้ว

      They didn't make a 2004 jeep Cherokee

    • @jmartinez2620
      @jmartinez2620 6 ปีที่แล้ว

      Same with my jeep.

  • @BasketballAve
    @BasketballAve 9 ปีที่แล้ว

    awesome video I love a challenge!

  • @mohamedkhalifa3422
    @mohamedkhalifa3422 9 ปีที่แล้ว

    thanks for this great video and for ways to explain problem can you tell me engine size to check wiring diagram thanks one more time

    • @SchrodingersBox
      @SchrodingersBox  9 ปีที่แล้ว

      +Mohamed Khalifa This one has the 4.0L

  • @jamesdewer
    @jamesdewer 3 ปีที่แล้ว

    Exactly my issue.

  • @ForkliftJoe
    @ForkliftJoe 9 ปีที่แล้ว

    Just how big is your garage (shop) anyway? 20x20? My garage is 20x20 and I can't get an extended cab pickup inside and close the door.

    • @SchrodingersBox
      @SchrodingersBox  9 ปีที่แล้ว

      +ForkliftJoe Yeah same here- if I have an extended cab i can barely fit it in if I move stuff off the walls and park it at an angle but it's not ideal at all. I need a 3 car garage!!!

  • @shanebrunette4399
    @shanebrunette4399 6 ปีที่แล้ว +1

    Crank position is on the bell housing

  • @whitetiger8652
    @whitetiger8652 9 ปีที่แล้ว

    Very interesting.

  • @rickjljr11
    @rickjljr11 9 ปีที่แล้ว

    It looks like that cam signal is 6 pulses per second so would that be 360 rpm or once per revolution?

    • @SchrodingersBox
      @SchrodingersBox  9 ปีที่แล้ว

      +Richard J Lebens I didn't notice but I would say if you are correct, it would indeed be 360 RPM on cam but at 2 crank revs per cam rev that comes to normal idle speed.

  • @gotenkoXD
    @gotenkoXD 9 ปีที่แล้ว

    I have that problem too and my cherokee turns off while driving, it have a new fuel pump, and the fuel pressure it's fine, I think is the sensor too, I can't wait for the solution :), BTW do you know what's the name of crank and cam sensor in Mexico? XD thanks for the video

    • @Avizponverde
      @Avizponverde 4 ปีที่แล้ว

      Gotenko crankshaft position sensor es el sensor del cigüeñal y el Camshaft position sensor es el sensor del árbol de levas

  • @mohamedkhalifa3422
    @mohamedkhalifa3422 9 ปีที่แล้ว

    check engine after you delete it comes back right away?

    • @SchrodingersBox
      @SchrodingersBox  9 ปีที่แล้ว

      +Mohamed Khalifa Every time while cranking

  • @chrischamberlain9801
    @chrischamberlain9801 9 ปีที่แล้ว

    thanx for the vid well done sir this guy knows his shit he has helped me fix my s10 pick up

  • @21D38F67
    @21D38F67 5 ปีที่แล้ว

    I can't find part 2

  • @chekelley6861
    @chekelley6861 9 ปีที่แล้ว +4

    You're gonna make us wait???

    • @SchrodingersBox
      @SchrodingersBox  9 ปีที่แล้ว +5

      +Che Kelley Hahahaha I am still editing part 2... It will be up tomorrow evening at the latest. Thank goodness it's a 3 day weekend or it wouldn't be til next week and I know you guys would kill me!!

    • @21D38F67
      @21D38F67 5 ปีที่แล้ว

      Still?

  • @JOHNPHUFNAGEL
    @JOHNPHUFNAGEL 9 ปีที่แล้ว

    I haven't finished watching all of the video yet but I wanted to make a comment before I forgot about it. When you was showing the signal for the crank sensor sometimes it can be missed when you have a drop out, I learned from scanner danner to set the scope to frequency and if you have a drop out its really evident, I know you had it on a long time base but I'm not sure if it was your camera but it looked like you had scope aliasing and that also can make it difficult to catch a dropout. Why didn't the customer bring it to you instead of the so called "PROFESSIONAL"? I work PT at Advance auto and you wouldn't believe the people that want to replace the computer! Today's ecu's are a lot better than in the 80's and 90's and are less likely to be bad, but they still want to change them and they usually come back and get my phone number so I can fix there car. Lol

    • @SchrodingersBox
      @SchrodingersBox  9 ปีที่แล้ว

      +JOHN HUFNAGEL Actually PCM's were just as good in the 80's and 90's but because they were new, not even the best professional techs were familiar with them when they were introduced, so they blamed the computer a lot.
      In fact, of the tens of thousands of PCMs returned to the factory during the 80's- only .02% were found to be defective. Thats like 2 in 10,000 that were actually defective.
      As usual when people do not understand a component, they are likely to replace it!!
      Good point about using frequency for the dropout- I didn't think of that and it makes perfect sense- great advice!

    • @JOHNPHUFNAGEL
      @JOHNPHUFNAGEL 9 ปีที่แล้ว

      No problem I like to help out when I can but I cant take credit for it Paul Danner is the guy that taught me that. Not sure if you watch his channel,but you should even a old dog can learn new tricks. I am referring to me not you.Lol I have always had a good understanding about electrical but he has taught me so much more.
      Great Job on the video cant wait to see what you find
      Im not sure what you have for sources but Mitchel Diy has never let me down I was using Alldata.com but I have had some issues with them

    • @techsavantlove
      @techsavantlove 9 ปีที่แล้ว

      +JOHN HUFNAGEL
      Matt and Paul do talk, and Matt has often repeated that Paul is THE MAN when it comes to the tough diagnostics, which we agree on.

    • @SchrodingersBox
      @SchrodingersBox  9 ปีที่แล้ว

      douglas lee Totally... I watch Pauls videos and find out I almost have no business doing a diagnostics channel lol- that guy is not human!!

    • @techsavantlove
      @techsavantlove 9 ปีที่แล้ว

      +Schrodingers Box
      It would be interesting to know the exact stat's about alternators and starters also. I have heard that a large portion that are returned actually function fine, but I don't know the exact stats.

  • @haidermnati5655
    @haidermnati5655 5 ปีที่แล้ว

    I have code 31, 51, 136, 753 and 1495 and the engine does not work

  • @christheother9088
    @christheother9088 9 ปีที่แล้ว

    Seems to me the computer knows perfectly well what is likely wrong here but chooses to be ambiguous about it.

    • @SchrodingersBox
      @SchrodingersBox  9 ปีที่แล้ว

      +Chris Gonzales Seems that way but it was correct 100%- you will see.

  • @davidgcavada
    @davidgcavada 8 ปีที่แล้ว

    If I can do it, you can do it.

  • @saman9129
    @saman9129 7 ปีที่แล้ว

    why don't you take a fuel pressure test ??? you are jumping the gun don't you think ... you have inj signal and spark what about fuel pressure . that would be my next diag strategy .

    • @SchrodingersBox
      @SchrodingersBox  7 ปีที่แล้ว

      Why would I possibly associate fuel pressure with a Cam/Crank code? That makes no sense

  • @tracycolorado
    @tracycolorado 9 ปีที่แล้ว +1

    First ,spray some starting fluid into carb , if it starts every time , then it has to be a fuel related issue

    • @byrysh
      @byrysh 4 ปีที่แล้ว +3

      Well to begin with it doesn't have a carburetor. Just go over there and sit in the corner and let the big boys play

  • @kkk82054
    @kkk82054 9 ปีที่แล้ว

    at 12:19 spark under the hood

  • @josephtucci3666
    @josephtucci3666 9 ปีที่แล้ว

    I do not want to sound like a jerk But I looked on my vantage pro and it told me ware the sensors are at and what to look for and wire colors PS It is updated to 2012 but I think yours covers 2004 IMHO this is ware the information on the vantage pro is worth the $ spent on it But I may be wrong Joe

    • @SchrodingersBox
      @SchrodingersBox  9 ปีที่แล้ว

      +Joseph Tucci Yes I did remember this feature when I booted it and so I did actually doublecheck my hunches using the vantage pro and it confirmed.

  • @nathanwood3679
    @nathanwood3679 6 ปีที่แล้ว +1

    They didn't make a 2004 Jeep Cherokee

  • @konstantinusstoyanov9749
    @konstantinusstoyanov9749 3 ปีที่แล้ว

    You have a great morals, amazing

  • @grzegorz16100
    @grzegorz16100 9 ปีที่แล้ว

    Why they didn't bring the truck to you straight away? Why people are stupid enough to waste their money in garages run by 98-procenters?!??! That is something I don't get. Even in my limited experience the biggest morons get more attention from customers even if I give them good diagnosis backed up with good explanation?! They still give the car to a moron who say (without any examination) : "It is pump [or whatever part]! I know because I had the same in my ford"

    • @SchrodingersBox
      @SchrodingersBox  9 ปีที่แล้ว

      actually- we will find out the answer to this question soon....

    • @grzegorz16100
      @grzegorz16100 9 ปีที่แล้ว

      Schrodingers Box
      I can't wait;)

  • @larrymencke8632
    @larrymencke8632 8 ปีที่แล้ว

    hello new subscriber here like your videos question have you ever watched scanner danners videos? he has a book he published online that is for sale for all the techs out there like you and me witch I think you would benefit a lot from I know it helped mea lot when I bought it might want to check it out great videos

    • @SchrodingersBox
      @SchrodingersBox  8 ปีที่แล้ว

      +larry mencke Yes I discovered Paul's channel almost exactly a year ago to this day and actually he and I have become good friends and I was hoping to even fly out to pittsburgh while on other business and do a video with him before year end!
      I bought his book and I also subbed to his premium channel.

  • @satamanschmidt3428
    @satamanschmidt3428 9 ปีที่แล้ว

    Your comment about professionals profiting from incompetence is dead nuts perfect. If somebody objects to this I'd like to know why. You've thrown $1100 worth of parts at this and it's not fixed. In what world should this be considered acceptable. Screw those that complain about the stance you've taken on this point Matt. There are certainly times I disagree with you, but, this isn't one of them.

    • @SchrodingersBox
      @SchrodingersBox  9 ปีที่แล้ว

      +SATAMAN Schmidt Then this is one of the times you are right ;-)

    • @DENicholsAutoBravado
      @DENicholsAutoBravado 9 ปีที่แล้ว

      +Schrodingers Box lol

    • @techsavantlove
      @techsavantlove 9 ปีที่แล้ว

      +SATAMAN Schmidt
      Matt and I and a few others talked about this a few months back, I don't remember which video it was under, but I raised the question of "why is this behavior not fraud"? If you look 2 or 3 months back, you might find it.
      I don't know what the ultimate solution(s) are, except that the best advertising is word of mouth, as they say. So when somebody has a history of getting ripped off (which is most of us), and then they come across somebody who seems to be both honest AND competent, they should STAY WITH that person, until they have reason not to.
      Seems to me (and I'm no businessman) that if you build a business slowly and gradually, but continuously, based on reputation and repeat customers, that after just a couple of years you'd have a pretty good business going.
      Just my thoughts.

  • @grzegorz16100
    @grzegorz16100 9 ปีที่แล้ว

    What happened with haters? No thumbs down?

    • @SchrodingersBox
      @SchrodingersBox  9 ปีที่แล้ว

      +Gregory May Lol they will happen, I assure you. I can not escape ignorance

    • @MrNATACUS
      @MrNATACUS 8 ปีที่แล้ว

      +Schrodingers Box LOL, THANK YOU!

  • @grantdethlefs8820
    @grantdethlefs8820 6 ปีที่แล้ว +1

    Get to the point!

    • @SchrodingersBox
      @SchrodingersBox  6 ปีที่แล้ว +2

      I did, you are just too dumb to understand what is happening. This video is way, way over your head.

  • @rjx757
    @rjx757 4 ปีที่แล้ว

    Do these guys like to hear themselves talk? What a waste of time!

    • @SchrodingersBox
      @SchrodingersBox  4 ปีที่แล้ว +1

      ROTFLMAO- waste of time... a waste of time is people like you who would replace parts on guesses because you don't learn how to diagnose. Learning is done with words and explanation. Stay simple and Rev up your Parts Cannon!!!

    • @rjx757
      @rjx757 4 ปีที่แล้ว

      Can't take criticism? Make better videos then. I don't just replace parts Jackass,. If I did, why would I check out your video? Put your brain in gear b4 you run your mouth. I was doing research when I came upon your lame ass video. And you split it in 2 parts? I couldn't finish PT 1 it was so bad. Like I said before you like to hear yourself talk!

    • @SchrodingersBox
      @SchrodingersBox  4 ปีที่แล้ว

      You checked out my video because you are a parts changing hack and you need my skills.