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No Start from a shorted MAP sensor (Honda, Acura)

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The methods shown for testing computer power, ground and 5V reference circuits can be applied to any year/make/model out there. This is a great video on what to do when you’re faced with a no start, no communication problem. The vehicle featured also had no spark, no injection pulse or fuel pressure during testing, all of which pointed me towards an engine computer issue.
Engine Performance Diagnostics chapter 9
Symptoms
- crank no start
- no communication with ECM
Fix
- replaced shorted MAP sensor
Tests shown
- how to check for scan tool communication issues
- using the check engine light during diagnostics
- how to check the 5V reference circuit
- how to check an engine ground for a poor connection
- how to use a wiring diagram to identify computer power and ground circuits
- how to locate the correct pins on a bulk connector using wire sequencing
- verifying your scope ground for testing
- how to check computer power and ground circuits using voltage drop
- how to make sure you’re connected during ground-to-ground voltage drop checks
- understanding 5V reference circuit design
- how to check for shorted 5V reference sensors
Tools used
- Autel MS905 MaxiSys Mini Diagnostic System with Connector Kit - USA Version
www.jbtoolsale...
- PicoScope 4425 4 Channel Standard Diagnostic Kit
www.aeswave.com...
- Digital Multimeter www.jbtoolsale...
Playlist
- (Chapters 9, 10 and 11) The 5v Reference and Signal Circuit Quick Tests
• (Chapters 9, 10 and 11...
Related videos
- Poor running, flashing CEL, no codes (bad computer ground) - Toyota
• Poor running, flashing...
- 1996 Jeep No Start Case Study Part I
• 1996 Jeep No Start Cas...
- Bad Engine Computer Testing Part 1
• Bad Engine Computer Te...
- How to check the 5v reference circuit for a short to ground (Cadillac)
• How to check the 5v re...
For more information on this topic, I have written a “field manual” called Engine Performance Diagnostics which is available at www.scannerdanner.com as an eBook or paper book.
Want even more diagnostic training? Whether you are a DIY trying to fix your own car, someone looking to become an auto technician, or a current auto technician that wants to get more into diagnostics, subscribe to ScannerDanner Premium www.scannerdan... There is a 14 day free trial.
On ScannerDanner Premium I will bring you right into my classroom at Rosedale Technical College. You will find page for page lectures taken right from my book as well as exclusive classroom type case studies. What is so special about these classroom case studies? I pull live problem vehicles directly into my classroom and we troubleshoot them in real time, using and applying the theory and testing procedures we learn during the classroom lectures. There is no better on-line training of how to troubleshoot automotive electrical and electronics systems anywhere!
Disclaimer:
Due to factors beyond the control of ScannerDanner LLC, it cannot guarantee against unauthorized modifications of this information, or improper use of this information. ScannerDanner LLC assumes no liability for property damage or injury incurred as a result of any of the information contained in this video. ScannerDanner LLC recommends safe practices when working with power tools, automotive lifts, lifting tools, jack stands, electrical equipment, blunt instruments, chemicals, lubricants, or any other tools or equipment seen or implied in this video. Due to factors beyond the control of ScannerDanner LLC, no information contained in this video shall create any express or implied warranty or guarantee of any particular result. Any injury, damage or loss that may result from improper use of these tools, equipment, or the information contained in this video is the sole responsibility of the user and not ScannerDanner LLC.

Опубликовано:

13 авг 2024

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Комментарии : 394

@simbad909 2 года назад

9 yrs later.. and im amazed how u do ur stuff.. a friend use to call me a jedi when i would fix his pc.. gotta pass it on....jedi👍

@ScannerDanner 11 лет назад

Just some fundamental knowledge my friend. This 5v ref. circuit is the same on every car. Thanks!

@scientist100 3 года назад

I've heard you say there are cars with 8volt reference signals. Is this correct? Maybe I'm remembering pull down or up designs. Thank you for the great content.

@ScannerDanner 3 года назад

@@scientist100 yes sir, Chrysler systems from the 80s through the late 90s used a 8-9v reference for the cam, crank and vss inputs circuits, while using a separate 5v ref for the rest of the inputs

@jonwally2002 10 лет назад

Love your videos. Just had to help another tech in my shop after he did an engine swap. Had exactly the same symptoms. He tried swapping the coil, crank and cam sensor from the old engine before I stepped in. After checking crank signal and not finding it, checked 5v reference and did not have one. Computer not so easy to back probe so started unplugging sensors. Found that in the rush of putting the engine back in, he had plugged the cam sensor connector into the coil. Unplugged the coil while watching the 5v reference, boom, 5v now. Easy fix but shows how easy it is to over look something so simple.

@turtlezed 3 года назад

I see this was 6 years ago but I am about to go and troubleshoot that exact scenario this weekend and your comment is more useful than you realise, I think you may have already cracked it for me.....I am already on a good path with this one, thanks for the 5volt input dude 😉 👍

@jonwally2002 3 года назад

@@turtlezed you’re welcome, hope you are successful

@andrewdomenitzdmd 5 лет назад

Been working on my own stuff for 50 years. Way back before all this complicated stuff. Always looked for obvious first, cracked disconnected hoses and broken wires, burnt wires, chafing wires. Blown fuses, open circuits. All we had were test lights and a multimeter. Now that we have cars on the computers and can bus system it has gone way complicated, but thanks to guys like you us do it yourself types can figure it out again. Back in the day I hung out in the local garage and watched. That is no longer really possible anymore. Thanks to youtube you can hang around thousands of garages.

@AutoTechHector 11 лет назад

Congratulations on your 2 years on RU-vid ScannerDanner. i've been following you since the RX300 misfire video and been learning something new ever since. Thanks to you (your E-book, case studies, and video lectures) i've been able to fix vehicles that the "Lead Techs" haven't been able to fix. THANK YOU!...

@liar8678 9 лет назад

scanner danner best teacher on youtube about car electronic ,briliant teacher.

@mannyfResh1893 11 лет назад

I'm happy that you enjoy your job very very well and share your knowledge to the technicians who wish they had their co-workers as friendly as you are to help them. I must thank you for 1.) Selling your ebook to me in a printed form 2.) For being a teacher/instructor for all technicians who seek valuable information and testing procedures that you offer us. I greatly appreciate it. Thank you.

@benji1990x 7 месяцев назад

I'm addicted to these videos just getting the hang of 5v references unplugging and reconnecting sensors I've ordered a snap on d8 triton was a trade in so got a deal on it now I'm going to start practicing using a scope and values still got a long way to go yet as I'm just starting but your videos are priceless

@ScannerDanner 7 месяцев назад

Thank you! When you're ready, join my classes I offer via my website. I have over 400 hours of training material, from classroom lessons recorded at the technical college i teach at, to exclusive case studies. Hope to see you there! www.scannerdanner.com/join-scannerdanner-premium.html

@mattdloughy5369 6 лет назад

I can't thank you enough for all your wisdom and generosity with it. It sounds crazy but a completed circuit can be applied to just about anything in life.

@ScannerDanner 11 лет назад

Thank you Jonas! and may God bless your mind as you continue to learn in this great field.

@jameritch6516 3 года назад

Would never have thought a shorted sensor could cause that. You guys are awesome.

@ibenripped 4 года назад

After spending a lot of time checking rechecking and re rechecking thinking I missed something, I come across this video that makes sense and is put in simple to understand terms. This procedure makes testing simple and quick. Thank you.

@ScannerDanner 11 лет назад

what a compliment. thank you very much for all your support!

@demontuning5512 5 лет назад

Lord of the 5V Reference Circuits. Good lesson.

@sivucit 11 лет назад

I have watched 1000's of videos from various authors around the world from UK, Australia etc , spend around 3000 dollar bought lot of dvd (trust me) so far, but ur ebook I bought costed just 30 dollar(not sure how much it is now) and I value that book then those 3000 dollar dvd's... u are the best so far. you know why because u are honest and humble. if the other author have this kind of knowledge like u have they would have sold for million dollar, u are a million dollar guy,

@mikembz1 6 лет назад

Paul i believe God all mighty send you to earth so you can teach us this a gift.thank you sir.

@ScannerDanner 11 лет назад

i am flattered, thank you. But i am nowhere near that mans level. He is so good at what he does. I have so much respect for him. Any class John Thornton is teaching is one that I am signing up for.

@ScannerDanner 11 лет назад

you are very welcome, and thank you for the comment

@buckrogers5893 2 года назад

I've seen a lot of troubleshooting videos on here this is by far the best.Your students are lucky .THANK YOU!

@ScannerDanner 2 года назад

Thank you!

@Shamus71 8 лет назад

I have a friend with an 05 Dodge Ram 1500 van who is having a similar issue as what you had going on here. It's an intermittent crank but no start, and "no bus" clearly indicated on the cluster, and no data link while this happens. This weekend we will be looking it over. He assumed possibly a bad crank angle sensor, I told him to watch this video since something is possibly grounding out the reference circuit.

@MrOscar442cutlass 6 лет назад

Probabky bad ecm

@RichardFiander 6 лет назад

As i research and troubleshoot my Element I am starting to think that mechanics are more electricians than mechanical specialists when dealing with cars. Thanks! Your videos are great and totally make sense to a rookie under the hood.

@joaojonasarendartchuk86 11 лет назад

Hey Paul if one day you decide to come teach in New York I will definitely be one of your students. Thanks for really teaching how to fix a problem NOT change parts. By watching your videos i decided to buy a Snap on verus pro and now feel like one of your students learning how to use and fix problems with you. Thank you very very much man. May God always keep giving you more and more understanding on how to fix and teach people.

@paul06660 Год назад

That is an awesome diagnostic video for someone who is not quite familiar with this situation. But early on in the video I could have told you that the plugs for the map and tps were mismatched. Happens most the time when someone is not careful in their engine swap and hooks them up wrong because they both use the same exact plug.

@XoFFoX777 6 лет назад

YEp ... great job and very good troubleshooting approach ... I used to do this sort of thing on a brd level at an electronics mfger where we have a test jig for a pcb and it tells us what test fails and then we find that area on the schematic and proceed from there. Golden rule of ANY electronics TSing is power supply power supply power supply ! As you were saying most electronics today are protected from short circuit and over current as well so it makes it pretty easy to track down these sorts of issue. Well done Danner

@AutoTechHector 11 лет назад

This is the kind of issue that would have this vehicle jumping from shop to shop with dozens of parts thrown at it..Very few techs would have figured this one out. You're just that damn good man!!

@amorozzo70 11 лет назад

been watching your videos,but this is the first time I write,thank you for all your videos, and this one is one of the best.

@jarinwilson9539 11 лет назад

why should you check for a good 5v Reference? Remember, the 5v-ref. circuit is an output signal from the module used for diagnostic purposes/feedback on wiring integrity. If this is not present, this indicates that the module is not awake. I've seen 7v-ref circuits, 10v-ref circuits etc, but 5volt reference circuits are the most common amongst vehicles, at least from my experience. Awesome video, I thoroughly enjoyed it

@PaulPhillipsFix 5 лет назад

Excellent video. I had a shorted TCM pulling down all com on a Mercedes I bought. You're doing a terrific job enlightening others. Thanks!

@johnmckamy6398 8 лет назад

what an excellent video, extremely good information for going after a no start .

@ScannerDanner 8 лет назад

Thanks John

@tnamen1307 4 года назад

@@ScannerDanner one confusion....the 5 v reference signal is shared to all sensors. Now, if the 5v signal to MAF is shorted, why the engine can start with the MAF sensor unplugged?? Is not that the ECM will not provide any signal to other sensors too? Please kindly brief clarify. Thanks.

@ScannerDanner 4 года назад

@@tnamen1307 key word "signal", a 5v signal wire on a digital MAF like on a GM, is a pull-down type of circuit. The computer sends 5v to the MAF and the MAF pulls it down to create a digital square wave pattern. This is NOT the 5v reference circuit. Yes, it is tapped into the 5v ref inside of the engine computer, but it is isolated by a current limiting resistor. In short, a 5v signal wire is totally different than a 5v reference wire. Hope that answered your question.

@tnamen1307 4 года назад

@@ScannerDanner that means, if any sensor or wire sharing a 5 v reference circuit or wire is shorted, then all the respective sensors will not work. Is this my understanding correct??

@tnamen1307 4 года назад

@@ScannerDanner and, another question relating to ac compressor. My car i20 engine is running very quiet as usual. However, as soon as AC clutch is engaged, I hear a squeak sounds and not metallic sounds or alike. The squeezing like sounds go away immediately as AC is off. Even with engine revs, same sounds. And with AC off, as I revs the engine, still the engine is quiet. How to find that squeaky like sounds and fix it? The AC is blowing cold. It seems the AC compressor is ok.

@InsideOfMyOwnMind 6 лет назад

I saw this one when it dropped and again now. Still an awesome watch.

@TheAdam212121 4 года назад

Thank you for being clear and concise in your videos. You may have just helped me figure out where to look next.

@dobroiuflorincristian4706 10 месяцев назад

omg ..so much to learn from you...and this video have 10 years

@ScannerDanner 10 месяцев назад

Still just as relevant today my friend. Thank you!

@spierotti14 11 лет назад

I agree with manny mr.danner we realy appreciate you sharing your thought process! Unfortunately in the field most other technicians don't want to teach what they know because they don't want you to start getting more of that work. I rely heavily on my youtube teachers to progress in this field. Thank you very very much

@leviscott8519 5 лет назад

Great instructional video as usual Paul! You are a diagnostic genius to say the least! All your videos are so helpful and chalked full of intuition and accurate persistence! I cant thank you enough! You teaching skills are both top shelf and down to earth. independent thinker inside and out the box. A++++++++++++

@nickayivor8432 2 года назад

Good Evening Sir ScannerDanner take care and have a great day Sir ScannerDanner Thank you tutorial great 👍 👌 From Nick Ayivor from London England UK 🇬🇧

@benrodeheaver701 2 года назад

So glad I found your vid ! Changed engine in an altima and same woes. The maf is the only thing I haven't unplugged trying to start w/ no spark. Hope it does it. Thanks.

@lucasogden8619 3 года назад

Very informative, excellent videos, explained well. Nice to not just hear how you do something but why you do it. Also like to see you fast forwarding in areas where it's obvious to do so because of repeated testing of certain components. Your an excellent teacher, look forward to more videos and will definitely take your advice and suggestions of tools and services available that you support that could help me become a better mechanic.

@naushadali95 6 лет назад

the best teacher in the world.you are brilliant sir

@bric2661 11 лет назад

Hey Paul, Great video you have convinced me to buy your book, all the best from the UK.

@ScannerDanner 11 лет назад

for sure it seems like it would be a great addition to the diagnostic tool box for that type of testing.

@Atacama777 10 лет назад

Excellent, definitely the best learning resource on the web.

@grosjean3 Год назад

Well done.So amazing to look at you and going stepby step and that referenced 5 volts is awesome.

@ScannerDanner Год назад

Thank you!

@kalindambozi2356 3 года назад

My best lecturer. Always wish i knew you earlier. Am learning alot. Thanks.

@ScannerDanner 3 года назад

Love this comment. Thank you

@import0408 11 лет назад

Omg this is by far my favorite video this is the stuff that will drive you crazy and you systematically took it on step by step

@malisa696 11 лет назад

Great case study Paul. We sure have to pay attention on those shared 5V references even if they coming from two separate pins in computer.

@princeclive1913 5 лет назад

Paul danner is the greatest teacher in the u tube there is no point putting tumb down... Mabe those who put their tumb down are those who don't understand or jelouse of his brilliance... Next time if you don't like his teaching you may fuck off without any comments I learned a lot from you Paul thank you ...CLIVE from Malaysia...

@ScannerDanner 5 лет назад

lol thanks man

@tigerksewsankar7667 4 года назад

Thank Paul for explaining the 5 v reg great job man thank you sir.

@DJDevon3 11 лет назад

Man what an amazing video. I learned a lot about the importance of good reference voltage and how sensors can be interconnected. Thank you. You are awesome.

@nestorfresno1 11 лет назад

Hey Paul great test, i agree checking for voltage references from pcm when you dont have communication the first step, test is to verify what the pcm need to supply, which is voltage 5v references ,totally agree,, thanks for sharing

@donaldyocum3570 11 лет назад

You do t he most amazing videos. I learn so much from you. You are one of the few teachers who explains things in a way I get it. You have helped me further my career so so much. Thanks Paul ! My biggest downfall is no communication. Could you do a video on that with a can bus vehicle where a module takes down the network plz? I don't under stand how to figure out which mod i/ node is taking down. He net. Thanks for all you do. You are an amazing tech and teach! Keep up the work

@Mulletsrokkify 11 лет назад

A superb logical approach. Another fault finding gem. Thanks for posting this.

@JoelAutomotiveInaction 11 лет назад

this is another great video always some thing to learn, good lesson Paul thank you . the best teacher I ever seen. your book is amazing

@timothyddibabisasso7109 3 года назад

Thanks for the great job of making us great technicians

@redsson6669 11 лет назад

excellent video paul i think between just these last 2 videos/ they cover all steps approaching any no-start condition.

@Amopower 11 лет назад

Another great video. Long time subscriber, and what you prove is that it doesn't matter what car you are working on, you dont need to be experienced with every single car out there, the concepts are fairly identical and therefore so can the troubleshooting. It almost makes me want to purposely create the faults you find, so that I can do the same tests to prove it. My luck though, I'd have the PCM without the "safety" circuitry to handle a short and would blow the PCM, lol.

@GRUSSNewton 11 лет назад

I wish we had Mitchell on demand wiring diagrams in the uk! Great video by a great teacher!

@rithychap91 8 лет назад

Thank you very much for that write up (video). It was very informative and very helpful in regards to "no start" issues.

@hectorvigueria378 3 года назад

60 ur. Old man and I love to work on cars engines .I always avoided eiectrial repair or troubleshoot but now I've so much off of his videos he makes it look. Easy and interesting scanner Danner day shit!!

@ozzstars_cars 11 лет назад

Amazing how sensitive the computer is missing just a few volts which can cause big problems. Great vid once again, thanks!

@FettManTAG 11 лет назад

I notice that the odometer reads 141,693 miles even though the engine was swapped out. Could that be a sign of the computer not being able to communicate with the engine? Every time you solve the issue I'm simply blown away. Thank you for the work you do and the effort you put behind these case studies.

@ScannerDanner 11 лет назад

I have not. I have seen the tool and it is pretty neat. I prefer loaded circuit voltage drop testing myself. I understand there is a need to unplug a circuit to test it at times and this tool could be handy for that.

@gregoryfairchild2460 3 года назад

"Engine swap" ran before..what changed? Look for wires not plugged in or grounds loose.

@HayesMobileAutoRepair 7 лет назад

thank you, this info was a huge help...the sensor did knock off my check ingine light and no start condition... anyway, all is good now..the computer was getting very hot during all my checking but now the fuel relay is malfunctioning and will not start normally... but it will start if I supply voltage to fuel pump... anyway, Ill look at it tomorrow.. thanks again..your awesome.

@Loudlevin 11 лет назад

Bravo, that is troubleshooting on another level. Great lesson.

@subaru733 11 лет назад

thank you i have been working on a 2006 subaru wrx no power to the pcm no power to fuel pump no power to injectors and i just went in to work and unpluged the maf and it started right up thank you

@rrmech11 10 лет назад

Excellent. Paul. Love the direction

@rubendherrera7194 4 года назад

my english its not to good but im learning all the inf you shareand at the same time im learning english thank you for techihng us God bless you

@ScannerDanner 4 года назад

You are welcome!

@Z14kt12timandjes1 2 года назад

I love the credits at the end...starring: a shorted map sensor 🙂

@ScannerDanner 11 лет назад

Yes! Not common but yes. So the process would be to check all powers and grounds, then disconnect ALL sensors that share the 5v ref. Then ohm the 5v ref wire to ground to make sure the harness is good. Then and only then do you look toward the PCM as the fault. At this point we then consider the other variables. Like in this video "2005 Chevy Impala Crank Sensor Trouble Code (P0335)" I almost replaced the PCM in this video for something similar. Variables upon variables my friend :-)

@TheOvnicar 11 лет назад

very good video amigo paul

@zvonimirbobic1093 7 лет назад

if there s check engine light, with the key on...could we assume that it s likely the shorted sensor/5v ref...rather than computer pwr n gnd issue?

@alabalanutnbolt 11 лет назад

another really good video. spot on with the method paul. learn along with danner is better than factory training.

@albertomendoza9565 2 года назад

Gracias, gracias, gracias!!! Straight to the point, and clear as daylight explaning. ✌😎 New sub. Stay 💪. Thank you very much.

@ScannerDanner 2 года назад

Thank you so much! And welcome to my channel

@ShiversRSS 11 лет назад

Great case study as usual. Thank you very much. I love learning and being stepped through your thought process.

@michaelpearce8661 6 лет назад

Awesum videos you make and yes I spell awesome differently than most people. I have my own reasons for doing it. Some = a few Sum = total. Awesum total amazement. Seems logical to me. Really liked your video, thank you for your time and what a gift to share with us.

@maggiereyes2903 6 лет назад

Once again dan the Man....super Awsome Knowledge...Almost Master YODA Status...Great stufff Keep the Knowledge a coming...Thanks U a Bunch...U dont Even know how much u just helped me out...Dan the Man!!!

@InsideOfMyOwnMind 6 лет назад

"There is no try. There is only do."

@cloud8056 10 лет назад

very good presentation on ref. voltage,and seeing if computer is alive.

@danielm.8301 9 лет назад

I I

@ScannerDanner 11 лет назад

We have 10 of them at the school and they have all been very reliable units. Never sent one in for repairs yet in the 2 years we've had them. These are the first gen. Verus units. They are not wireless. Watch my three part Jeep No start video (10 minutes each) to answer your other question. I have it hyperlinked in this video

@christopherreynolds8247 4 года назад

Wow this is so sweet you are so good in what you do i keep looking at this video over an over very nice.

@johnpaulgarrett1 Год назад

Best diagnosis video i have ever seen!

@ScannerDanner Год назад

Thanks man

@nestorfresno1 11 лет назад

very good testing procedure diagnostic flow chart.thankyou for sharing we always learn somethign from you....

@ScannerDanner 11 лет назад

check your fuel psi and if it has a MAF sensor make sure the air intake tube has no cracks in it and that the MAF sensor checks out good.

@frugalprepper 7 лет назад

"It isn't just like a regular 5 volt regulator that you buy from radio shack and you short it to ground and you kill it" - The LM7805 has short circuit, overload and thermal protection built in.

@dblr616 11 лет назад

The next time this car is a no start im gonna go out on a limb and say it will be the never start battery, i love walmart but hate there batteries;) Thanks for the amazing videos Paul.

@fivefortyeye540i 11 лет назад

Luv theses type of case studies, great for dirrection base.. GURU!!!

@redbread9588 8 лет назад

this remind me of a time when i was working for a mazda dealership and was first starting out and i had a mazda 626 that was tow in and i try to dianose what was wrong. well i gave up and went and got the lead tech. he came over with a basket of know good electronic parts and told me to try the maf senor first. and what he meant by try the map sensor first was swap it out and see if the 626 will run. well i swap the maf sensor and the car ran. so we informed the customer it need the maf sensor. after the dianose i went back to the lead tech and asked him why the maf fixed the car. and he told me that he dont have a clue. just that his first 626 that he had the problem with took the whole day to figure out with mazda tech support and he just started swapping parts till he found the problem. thank god the car was under warrenty and all the parts where cover. well after seeing this video now i know what was probably happening. we had all the same syptoms as this honda did. by the way there was a computer in that basket that he handed me. be he couldnt get into the computer with the scan tool. so he replaced the computer. Lol im glad i didnt replace the computer. we didnt have a scanner danner back in 2002. thanks for the videos you do.

@dondesnoo1771 7 лет назад

I once had a 88 aries wagon would just stop unplug map would run replaced numerous times used too keep one in the car a friend at Chrysler told me to move sensor above engine from inside to firewall water accumulation & freeze in winter never happened again

@verajavi12 6 лет назад

Randy Johnson where can I buy a magic basket of goodies like your buddies

@troythoreson8388 3 года назад

This really help me out scanner Dan cuz I have the same problem and thank you so much I hope I figure it out I need your help I have a Mercedes Benz 1998 E320 on trying to figure out I'm just learning this wire thing I'm a good backyard mechanic but anyway thank you so much

@ScannerDanner 3 года назад

You are on the right channel to learn the electronic and electrical side of the car my friend. Thank you!

@troythoreson8388 3 года назад

@@ScannerDanner I have been chasing a bad wire for a month it was bad when I bought the car 2yrs ago it had bad map sensor, I drove it for quite long time then it started dying out let sit it wood start drive die start die u no replace map egr cam sensor crank sensor I took battery in out so many times too charge now the whole system must b shut down but I still have not pinpointed the bad wire I'm on top of it but too stupid 2222 figure it out I do not want 2 get beat by this because I have a lot of pride for myself but its gettin me puzzled I plan on drivin 2 FLA. For winter it's a great car when runnin I need you 2 look or let me talk 2 u about it I got $$$ and a cell let me know if we can work sumtin out PlEASE you will like me I'm a 56 yrs o'l schooler but this mercedes is something else I'm used 2 69 70 80 79 chevelle and monte Carlos let me know Thank you so much troy thoreson hope 2 here from u

@alexsenicynlv6563 11 лет назад

Thank you! very good,very instructive video

@mahdijoumazadeh996 8 лет назад

can u interduce again any website that can i can wirind diagram and how much i have to pay ?

@rickchapman3707 9 лет назад

This is one of my favorite videos really enjoyed this one!!

@johnavila7942 6 лет назад

Another simple video that is understood

@E99584 4 года назад

Is it possible to have a pcm problem with not putting out a 5v? You were getting 1.7volts right at the pcm. If you still had that reading even with all the sensors unplugged would it be a pcm? or would you first check the 5v ref wires from each sensor to pcm before condemning the pcm?

@XoFFoX777 6 лет назад

One other mention I forgot ... when the MAP is connected and I measure ohms from reference to signal for the MAP I get only 50 ohms. This to me seems very low across these two points ... if it is too low then the problem is in the computer me thinks ? Which is why I took it out and will open it up and have a look but as I said below ... the junkyard MAP shows 4.6v across it and ref which is waaay too high should be around 1.5 or less.

@ScannerDanner 11 лет назад

you got it my friend. once you know fundamental systems, all cars are the same! Not that you should do it, but every single 5v reference circuit that I have seen shorted to ground, comes back to normal after fixing the short. On some of these you have to turn the key off, then back on for it to come back. Not sure how the PCM is protecting it? Maybe some type of PTC resistor? Anyway, I wouldn't do this one for practice :-)

@85nissanpickup27 6 лет назад

ScannerDanner so that means need a new map sensor?

@ScannerDanner 11 лет назад

I would say only if they are using multiple reference circuits or are somehow able to isolate certain branches of the reference circuit that are drawing too much current flow. I have not seen that yet. You short a 5v ref circuit out and the PCM is "dead" The 5v ref. circuit is the main lifeline of the computer system. It cannot operate without it.

@tunespt 11 лет назад

Thanks for the awesome video and information! It really does help to get things fixed faster, mechanics are starting to hate me :D

@tigerksewsankar7667 4 года назад

Sanner D you are the man thank you.

@Altermyego- 8 лет назад

Awesome video actually all your videos are awesome - I'm experiencing similar symptoms and after watching this I'm fairly convinced and hopeful that my issue will be the same. I've already gone through the ignition coil module OPTi spark you name it thank you

@ScannerDanner 8 лет назад

+Kevin cool. Let me know if you fix it

@Altermyego- 8 лет назад

+ScannerDanner Thank you so much for your reply... You're truly an amazing technician and a selfless person to share your knowledge and experience, especially at the level of educating others for free. • on my 94 Z28 5.7 L, i took it to an (alleged ASE tech) to work on my vehicle, which I literally never do ever. ( in lieu of my depression & severe anxiety disorder) - "intermittent stalls and no starts" The asshole - "oh, its the opti- $900. Immediately after leaving the shop I go to the car wash & when I try to start the car after washing it, crank no start! "exact same symptoms as when I took it to him. I'm so fucking angry I cant figure out how I'm going to handle this. I did call him right after it wouldn't start of course he didn't answer, it was 20 minutes till close -voicemail: me: " I'm leaving my car up there exact same symptoms"...

@XoFFoX777 6 лет назад

If I have the right the gear I can fix the computer if it has an issue. Schematics are a must ... without them you are flying like Luke Skywalker ... by the seat of the Force. I do have a question as I am working on a 2001 Caravan which no longer runs and suspected the MAP sensor ... sure enough it was pulling my reference down but when tested out of car it was shorted then it wasn't then shorted again. SO put another junkyard unit in and it still won't run ... this time the junkyard unit has a good ref but the signal is nearly the same when it should be around 1 to 1.5v ... it sit at close to reference at 4.62 ish ... so it's the opposite of a short ... and it won't budge under vacuum ... so what ? the diaphragm is stuck ?

@ScannerDanner 11 лет назад

I'm not but thank you Hector! You made my evening.