I loved this series and learned a lot. Thanks for that. My dad had a favorite saying: “When the only tool you have is a hammer, all problems look like a nail” I now have another nugget of wisdom courtesy of Eric O. “When you have an electrical problem, get a big yellow wire nut” 😉 Thank you Ivan.
I have to laugh, I recently started watching both of you guys because I find your content valuable because you guys do things the right way and there’s always something to learn. But what was kinda funny to me is I never knew you guys had collaborated on jobs until I found this case study. Cool stuff!
That is impressive. One of the best technical series I have ever viewed. Great job sticking with it, and not shying away from any aspect that did not have a solid verifiable cause.
Basically what really made this problem was a mismatched harness and PCM. That is enough to screw with anyone. Your original diagnosis was correct, no ground.... and if you hadnt taken the extra step to think it out (which is what gets you 100 marks for effort) and determine the that harness was wrong. It would have been so easy to replace the computer which is what the first shop also did (and got the same codes, you almost made the same error). I almost want to think that 99% would have made the same error in thinking the PCM was bad. So many times wiring colors dont match but in this case that was the real evidence. WOW and amazing. Edit: Basically all of the O2 sensors are linked together in the harness at S024 & S023 and grounded at Pin 69 on B-21 connector. Also note that the original Oxygen sensors were also shown to body shield grounded at Ground Point #11 ( I assume for noise shielding)while this was not the case for the 2006. (at least not shown on the diagram for the 2006)
@@JOHNSUE28 Pine Hollow Auto Diagnostics 5 years ago +Mike Brennan That was Eric's decision to make. Basically it would kill several birds with one stone and make the harness correct to the car and avoid any potential confusion down the road!
At the end of the last video, when he took his finger and wiped out the ground inside the PCM, I said (out loud even) 'Check both sides of the plug to the PCM!' My wife thought I was going over the edge, lol,lol. Of course, I was just thinking broken wire somewhere in the harness or bad pin in the plug. But that would have gotten you there. Anyway, great video and you guys make a great team!
I commented on part 2 three years after it was posted and my guess was that they replaced the computer with the wrong one and I didn't think the computer was actually bad either so I am glad to see that you guys figured it out. I would like to think that I would have figured it out as well but I can honestly say that I have never came across that scenario in my 30 years of wrenching, but I have figured out many issues that other shops couldn't figure out. I did have one that I never did figure out once and it still haunts me to this day, but nobody else figured it out either so there is that.
Awesome diagnostic learning for all of us. I would have been lost for sure, no way would I have the info or knowledge to figure that one out. Twisted cams , wrong engine harness - ha what's next. You guys both rock !!!
Steve Rob HAHA I am thinking you are the only canook I know that pulls off the stuff you do... the Coors Light womens beer vid put it over the top haha
incredible guys! top notch investigation! that vehicle would of been a basket case and would of been at many shops and probably never figured out. I need some of those clean air sensors for our cars in Grand Blanc Michigan! lol.
As usual another fantastic series ! Eric and Ivan I have to thank you for the time you put into making these videos. Thank you guys for making me a better technician !!!!!!
Good detective work guys. Perseverance, patience, resources, logic, experience, knowledge and skill pays off. SMA/Ivan=1 : Butcher Raped Mitsubitchy=0. I experienced a similar situation where the vehicle was bought at auction with no known prior history. After many hours, diagnosing, much searching and researching we discovered the vehicle had been in a serious front end collision(CarFax) so bad that from the firewall forward was from a similar but not exact donor vehicle. It was finally determined that the original vehicle was a California vehicle and the donor was not. It was also a mid model year manufactured vehicle with VIN break harness revisions. We were able to ID the harness from a part number tag on the harness and it did not match the VIN for year or California emissions. Performing an engine SN decode we discovered the engine was not a California emissions compliant engine and was from a different model year. I don't know if it would be legal in NY, but at the time in our state it was, we changed the PCM to a 49 state unit and all was good. After the PCM change MIL off and we cleared a laundry list of codes, cleared up rough idle and emissions passed with ease including the rollers with exhaust sniffer.
I'm resting today cause of medical issues and watched all three parts, I loved it, listening and watching the whole diagnosis. I wasn't all that surprised when the color codes didn't match, I've seen it a few times on vehicles built at the end or beginning of a model year or repaired wrecks. When I worked at Ford we bought a new 93 Aerostar(great truck) that had all 94 harnesses, dam seat belt warning light wouldn't go out, chime turned off ok, took a few days to figure it out, replace two seats belts with 94 pieces, good to go, it was built the day before they converted from 93 to 94. Great series.
Thanks James! Ah the good old cross-over years. Always problems to be had on those models. I always thought the Aerostars were a cool van design. Never drove one though. I hope you feel better soon!
I have to go to sleep. Getting up early to do a Mustang starter at 8am. Gonna finish looking at this video tomorrow. I am excited to hear how the initial bad ECM not grounding the O² sensors morphed into an alternate diagnosis. You two Sherlocks are tenacious...
i had to do this on a 99 grand Cherokee with California emissions. engine harness had melted in spots, went to junk yard and got a harness from a 01, i knew going into fixing it there was wiring differences. only because could not locate a cali harness. the most difference was in the o2 sensor wiring. had to re pin about 8 wires. printed out both wiring diagrams, also the coil rail wires were pinned differently and after getting all the wires to match the 99 harness. it worked perfectly! I was thrilled considering it was sitting at a mechanics shop that have gave up on the vehicle. its a great feeling when it all works out and you figured it out! good job guys
Gem of a diagnostic series. Relentlessness (if that's a word) from both of you. To keep people's attention in this scenario takes not only bright heads but the enthusiasm and chemistry you two have working together is easy to see. Never for a second thought you guys were gonna let that problem whip ya. Thanks for the upload !
It took a real meeting of talent of both Ivan and Dr O to figure this one out. What an absolute pig of a diagnosis. This was rocket surgery almost up there with that Hyundai with the warped cam shaft. Of all the things to be different on wiring harness. It could just have easily been some different wires and it could have damaged the PCM or caused a no start condition when they plugged it all in originally. Interesting stuff on the whiteboard of knowledge as well. The one thing about voltage that often trips people up is voltage people don't necessarily understand what it actually is. The way I've always understood voltage is that its a measure of potential difference between 2 points on a circuit so its important to understand what you are actually attempting to measure otherwise it can lead you down a blind alley. I'm self taught in the basics of electrical theory, but i've learned a lot more seeing it applied!
Awesome work guys.Sometimes you just need to have a cup of tea and let the penny have some time and space inside the old noggin to drop. The time to sit & work through where you went left instead of right after the fact is invaluable. This RU-vid thing is awesome & i don't think i would be speaking out of turn if i said everyone who invests the time to watch this series will have learnt something. Thanks for putting your time in we all appreciated your efforts......
My immediate thought when you first mentioned that the wiring diagram indicated that it matched an '06 was engine swap. You guys are fantastic and I enjoy both of your channels.
Omg I thought it could be a different wiring harness but that was only a passing thought. Never really thought that would be it. Glad you guys found the problem!
From my Purely electronic background , for all measurements I take a reference point ground as closed to input circuitry as possible (one of the battery ground wires going to pcm with least noise). So very good conclusion .It is also faster as you are probing with single probe .Thanks for a great video
I had a 06 f250 that someone had swapped the frame and powertrain out with an 04. 2 wires different in the whole harness. took me a bit to find it but eventually got it fixed. great job guys keep up with the awesome videos.
Great detective work guys to never assume anything until absolutely positive. The different wiring harness diagnosis was just brilliant. I guess the moral of the story is, " take with a pinch of salt" what people tell you when you're buying a second hand car and steer clear if the "money light" is illuminated. Ps. Someone is making a killing on those OEM Catalytic Converters - "ouch."
Wow I know this was some time ago for you guys, but brilliant series and so much to learn. So a big thanks, I could never have thought that would be the outcome. Slight disappointment we didn’t get the, ‘there’s your problem lady’ probably my favourite bit of any sma vid 🤪🤣👍🏻
Great job!! You guys need to go hunt for jimmy hoffa, I bet you two could find him!!! After that, work on the "WHAT WOMEN REALLY WANT" question!! I hope you guys had as much fun making this film, as we did watching it!! Many thanks to both of you for an enjoyable experience!
Holy shit!!!!! I called it in part 1!!!! When you guys mentioned that all those other diagrams were matching but they didn’t match the wire colors on the car, along with the harness being all loose and run badly in the car, I thought it was that someone put the ring harness in it with a swap. 😂. I finally got one right!!! It’s probably because I did a swap on a Honda and did this same thing. 😂
Awesome 👍 We have an 88 Toyota truck with the 22. It had mass air flow codes which tested out crazy. The following morning I removed the PCM from it's housing to look for the open on the sensor pin. The pin was not there. Called the dealer for the correct p/n. Got it from local vendor and MAF is still fine. Needs a transmission.
I'm very cynical about this CARB certified nonsense. It seems like great legislation to help OEMs make more money on older cars. Makes me appreciate AZ so much more. $90 for a magnaflow direct fit cat and I passed emissions no problem. On a positive note, you guys did beautiful investigative work, from the diagnosis down to the explanation of why the problem occurred in the first place. You will never see gold like this on TV.
In Massachusetts you need to have a state inspection performed within 7 days after registering a car, even if a state inspection was done with the previous owner two days before. It protects the buyer from crazy problems like this. A person selling a car can be liable if it will not pass inspection with the new owner, but I believe that's only for cars worth 1500$ or more (I need to look up at what cost it applies to). You two guys are great techs for figuring this one out, I hope it was as profitable you. I got a lot out of it.
This was a great set of videos! Having worked in late model vehicle wrecking yards in my college years, and personally changed out engines with wrecking yard engines, I actually suspected the harness 20 mins into part 2! When your wiring diagrams didn't match up on any of the sites and you said you had a 2006 diagram that was exactly right I was suspicious right then, considering the scan data didn't match the scope/sensor data. I also recall in part 1 you said the previous mechanic supposedly switched the PCM with a known good one. One side note Eric, (and anyone else watching) I've seen you go to the salvage yard in your videos and clip harnesses to grab a part. Having worked in wrecking yards it was a BIG no-no to cut wiring harnesses just for this very reason. When someone needs one they NEED one. People used to go out to the yard looking for something and come back in with a small pigtail from a harness. When they asked how much, the counter guy would often say something like, "$50." Then the customer says, "What??" The counter guy then says, you just damaged my $50 harness on that car I paid thousands for at the auction. I can't sell the harness now. That said, we sold very few whole harnesses...but it was very taboo to cut them. Great detective work Ivan and Eric! I was glued to this series!
Awesome series! That said, one huge clue that would've put y'all on the right path sooner was the negative voltage reading. Basically, there is no such thing as negative voltage - like y'all mention at 36:00, the reading is just a difference between two points. So if you're probing across a sensor signal and ground and you see a negative reading, it automatically means that the ground is being pulled high. And in this case the specific values suggest that the ground is being weakly pulled up to B+ (likely due to a different connected circuit that's supposed to be pulled down to ground, except the ground is floating) From there, if y'all had started chasing grounds immediately, you would have short-cut a whole bunch of work in the middle. Regardless, though, awesome diag and I never suspected the surprise ending 👍🏽
Hello Guys, Great Video series, My Grandmother used to say to me after something happened "What Have we learned from this" In this case, If I have a problem like this, I need to go to New York or Penn. and have one of you guys fix it. I enjoy the Joint SMA and Pinehollow Videos, you guys are fun to watch...Thanks Guys.
In this trade just when you think you have seen everything something else comes along. Sometimes thinking outside the box really works in regards to the engine being replaced. I don't think I ever used the harness on the replacement engine. I always thought the were gonna be different besides, the wreckers usually chop them to pieces anyway. Awesome job, both of you.
I came late to this party, but after the initial finding of 11 volts (!!!) in the scan data but normal voltage on the scope, I would have given you 30-70% chance of ground problems. What really got my interest (although I would never have guessed the wrong harness - super sleuthing by Eric!) was the two ground symbols in the ECM. Before I started shaving I got into electronics. Most of the literature I had to work with was from the '50s and very early '60s (this was in 1965), tube type and early transistors. In those days it was fairly common to identify two grounds; the rake symbol for chassis ground and the upside-down Christmas tree for a ground bus (typically signal ground, but sometimes DC ground). There was often a separate connection shown for an interconnecting wire. Without that the Christmas tree ground floats and hilarity ensues. I thought there was going to be such an interconnect wire coming off the ECM. Anyway, my hat is off to both of you. It is amazing such talent exists in the real world today.
As I have applied the star ground concept in PCM design, the star ground (Signal Return, Power Ground, Chassis Ground (which may be through a resistor or capacitor or both in parallel, etc.) tied together in a star configuration to minimize any modulation of a common ground impedance. So, the star ground is internal to the PCM and not external using a splice to ground. This makes sense if you are trying to minimize the number of PCM connector pins to control all of the circuits. However, with this PCM design there is no shortage of connector pins, and for some reason (probably noise or EMC) the decision was made to complete the start ground external to the PCM via a signal ground splice. So, the 2004 harness has the splice and the 2006 harness does not.
They say.... you never really learn until you actually do it. Watching these guys is required for any mechanic.... and, guys, I get it. When I was a popular music radio DJ the last thing I did when I got home was to listen to more music. So you mechanics work all day doing repair and then I tell you to come home and watch more???? But Eric or Ivan usually show intruguing problems.
Ivan. What a perfect name for a nerd genius. Did you get beat up in school by a guy named Bubba? I watched all three videos. Excellent teaching. Absolutely excellent. A complete thought process of two very intelligent individuals using their minds together. No pride, no ego, just thought process. The summary at the end was just so excellent. The major improvement for me was when you said something like, "this is where we get confused". That sunk in for me. Thank you. Now me being the way I am, I ask myself where did you guys go wrong? You had 4 o2 sensors and I kept asking myself, why do the test them all? What is it they all share in common? Believe me, I did not know it was the ground, but if you think about it as hind site, it was obvious and there all the time. If 4 wheels on a cart all make the same noise, what do they share in common? What baffles me still is why was that one o2 sensor so odd with its voltage. It would be nice to scope the printed circuit board, but man, there is no way. I kept thinking a bad capacitor, or a diode on the board the whole time. Ha Ha. I am old school all the way back to from vacuum tubes to transistors. You guys are awesome.
Blows.My.Mind. - That was awesome, and if your wire colors don't match, verify with 15 differnt sources...lol Great case study, stories like this can only be written by life itself...no one would believe the story if you made it up...
Also glad i don't have to worry about rust anymore. Especially when up north when I'd service cars alot of times youd see the fosilized remnants of what once was.
This was really .... REALLY nice...!!! bravo!! and a great job on comparing o2 sensor to normal sensors, as it needs to be tackled differently (or at least bearing in mind that it produces its own voltage... this is when bias voltage (chrysler?) helps... Cheers! and now you're talking about the bias voltage, so i was hasty...
Holy crap! If we had a internal WD of the computer it would have jumped out or valid WD for the vehicle it would be easy but great catch...could've changed a good PCM. Component Test and Troubleshooter with SureTrack are great tools provided by Snap-on! You guys are usually thorough & I don't know what is edited out so I just go with what you show us and know in the end it will be a good fix and be able to explain the diagnosis. DVOM potential and connections can get you in trouble but the wrong harness in the car can really get you in trouble b/c normally that is not in your train of thought. The part that was unanswered & threw a twist was the -6 & -10VDC coming from BISI computer grd pin and in the end of Part 2 you had 12V at the B1S1 ground pin accounting for the 5V BISI processed data which would normally point to a bad PCM so what triggered you to dig deeper...was it the fact that by supplying a ground all the sensors worked and the PCM started reading correctly I would guess? Again great troubleshooting & good editing to put a twist to it. As always nice case study and great learning experience for all!!
+Robert Hayward Hey Robert, great question on the B1S1. So for the 2004 model year, that PCM pin is explicitly listed as "NOT USED". So to explain that "soft" +6V to +10V on that pin...your guess is as good as mine. But since that pin isn't designed to be connected to anything, I guess it doesn't matter for the operation of this car lol
+motoYam82 Ivan, I don't know about "super clean special oxygen sensors" but i have an 04 outlander with the same 2.4 engine and when you shop for 02 sensors it does specify different part numbers if the vehicle was made after march of 2004. Not sure if it applies in this case to the galant or not.
Great job. I'm afraid this car would've burnt me. But, maybe not. The last thing I ever want to do is call a pcm. So maybe I would've figured it out. Idk man. I'm glad you guys went through this before me, hahaha. I definitely learned a few things for sure. Thank you so much.
Eric, I think it was in part one, one of your subs said, ( not sure who ? ) and I was screaming at my screen in agreement, to verify the integrity of the grounds through the PCM connector. He said to check for spread pins etc. If you did, it would of shown that you had no ground on those pins and maybe, made you dig deeper faster? But dam, that was some good detective work ! What made you dig deeper, the fact that after supplying a ground, the PCM worked fine. What, did you ask yourself, how do I call a working PCM a Bad PCM ? That would of been a pretty tough call for anyone to make, To me what I have learned from this vid, if you have something odd going on, like you did, never overlook anything such as the wire colors ( hindsight is great an't it ) LOL ! Stop and think about it, the most important clue was staring all of us right in the face. ( THE WIRES DON"T MATCH, DAAAAH ! ) LOL! Most important of all, never stop asking WHY ? If you don't, you will always find the answer ! Once again, GREAT DETECTIVE WORK and GREAT FIX to both YOU and IVAN !
+Billy R Haha thanks Billy R! Yeah hind sight is one of those things I always wish I had before hand lol. I mean looking back, shoot we could have figured it out in 5 minutes right!? The answer was there the whole time just like it always is and like you say "just keep asking why!" That has gotten me pretty deep and frustrated before but it sure is good to come out on top no matter how ya get there in your diagnosis along the way. It is great learning along side with Ivan I know that!
+Dick Fageroni - very good points but considering that the wiring matched another year which is often the case it is easy to disregard what is staring you in the face !
+Dick Fageroni Yup the test light would have (and eventually did!) save the day here from the start. After this case study, it has become my standard procedure to verify traditional O2 sensor wiring integrity at the connector with a regular test light: Connected to Battery NEGATIVE: 1) Check for constant feed on the heater ckt. Connected to Battery POSITIVE: 2) Check for heater ground-side control when vehicle started. 3) Check for (+) signal circuit integrity by driving voltage high and confirming signal pegs high on scan data. 4) Last but not least check the signal GROUND!! It should light the test light, at least dimly. Obviously there are variables here too, but these simple checks can save a lot of headache!!
Good job guys, know the feeling with trying to sort out accurate wiring information. On Buses I have to deal with multiple vendors putting there harnesses together with multiple colors. When I work on multiple systems I draw out the entire circuit on paper so I don't loose track where I'm at.
Don't know the exact count but yes the newest buses we have contain over 20 modules. Sometimes yes it drives me nuts a little but I guess my patience helps with this,lol. Good thing I enjoy what I do for a living.
+busjockey1 When I worked in the truck shop for Cat , Cummins, Detroit Etc.... the thing I hated was that all wires were white! They all had little tiny numbers on them to I.D. the circuit...
+South Main Auto Repair Cool you have HD experience! You are right about the White wires. That's how Thermo King does it too. Of all the Bus Manufacturers I would say Gillig schematics are the best labeled. They write down on the wire what the circuit is so if your looking for the headlight circuit it says headlights on the wires. How long ago did you work for a Truck shop Eric? I have been doing this since I was 19.
Great video series , that was brutal. I got to this video looking for what could cause p0160 b2s2 on a 2001 maxima. It’s comes and goes. Happens more when the car is just idling on a cold day. I got it to still pass state test. Barely. We’re allowed 1 category as not ready yet on 2001 model year in my state.
This is a cautionary tale for people buying a car. If the SES light is on but the car seems to run fine, that doesnt mean the fix down the road will be cheap. The check engine light has a $ on it but doesnt have numbers next to it.
