VW Passat No Start - an SDP Case Study (Part 2) - [Bad Sensor Ground]

This is part 2 of a 3 part case study where I navigate through this unknown problem live with my class at Rosedale Technical College. We will dissect this VW completely, showing the exact cause of the problem. As with other classroom case studies I will be using any and all possible testing procedures to narrow down the problem area. Speed is not as important as learning these methods. But you guys that have been following along already know that. It's why your here!
link to part 3 • A Smoked ECM AND a Jum...
Symptoms
- no start
- no spark
- no communication
- no fuel injector pulse
00:00 - beginning of part 2
01:37 - identifying a shielded VRS type crank sensor circuit on a wiring diagram
03:08 - illustrating a dual cam system that uses a single cam sensor
04:19 - identifying a hall effect type cam sensor signal wire on a wiring diagram
05:30 - pierce testing at the PCM
06:05 - cmp and ckp lab-scope set-up
07:20 - waveform analysis of a failed start attempt
20:00 - determining circuit design by unplugging the sensor
23:40 - check your meter- dangers of trying to check voltage with meter leads configured for amps
26:40 - sensor signal terminal spread apart by front-probing
27:30 - bad sensor ground found while checking connector voltage
29:30 - using wiring diagram to identify sensor ground
32:40 - finding low 5 volt ref with 4.2 volts on sensor ground
37:30 - checking sensor ground at computer
43:00 - using a jumper wire to pull a bad sensor ground down to zero
48:50 - using wiring diagram to locate and check computer grounds
52:11 - outtakes
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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.scannerdanner.com/join-sc... 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.

[@ScannerDanner]

My apologies on the Part 1 video already being available here from 2019. I did not realize I used part of this series in the past to promote SD Premium. Anyway, here is part 2 of 3. I will have part 3 up this Saturday at noon (10-22-22). Premium members, you will find this series in my "No Start Case Studies" playlist right here www.scannerdanner.com/scannerdanner-premium-chapters/no-start-case-studies.html For you guys that are not SD Premium members yet, you can sign up for a 14 day free trial and then immediately cancel your subscription and you will still get the remainder of the 14 days without worrying about being charged the $11 for the next month. But seriously, where are you going to get this type of training for $11 a month? No where! Hope to see you guys there. Think of it as channel support for us here on KZbin, with a serious benefit to you! We have over 400 hours (500+ videos) of training material and counting!

[@saadalkhefagi9343]

What auto diagnostic database are you using?

[@ScannerDanner]

@@saadalkhefagi9343 ShopKey/Mitchell On-Demand

[@tmanda323]

@@ScannerDanner for VW/Audi use elsawin..

[@tomtke7351]

I'm impressed you actually not only tolerate students throwing out ideas but YOU ENCOURAGE IT! Students are, thus, very engaged MENTALLY!

[@ScannerDanner]

My favorite classes are those with active student engagement. And with this class being a "live" problem car, where I don't know what's wrong with it, having their participation is even more important. Thank you!

[@LynxStarAuto]

Why wouldn't a teacher encourage ideas? That's part of the process.

[@tomtke7351]

@@LynxStarAuto Yes! I agree with you. What strikes me as different is these students are fully allowed to just JUMP IN.. no polite hand raising waiting for recognition as is typical protocol... I'm with YOU these students are given green lights! THESE STUDENTS ARE BOTH INTELLIGENT AND FORTUNATE.... Troubleshooting vs generic R&R requires lots of deep thinking.

[@LynxStarAuto]

@@tomtke7351 yeah, that's how it has to be for them to learn. This industry is as much hands on as it is theory.

[@rickrogers2649]

Just an old retired guy here who is using your e-book and videos to try to stay in the loop as best I can. I have always been impressed with your diagnostic skills but after watching these last two videos I am also impressed by your students. You must be doing a great job with them Professor Paul. 👍👍

[@ScannerDanner]

Thank you! This was a really great class and was actually the last day of the term so you can really hear their engagement and what they've learned.

[@howlinhog]

Let me get a jumper and make this happen. Last famous words. LOL

[@ScannerDanner]

Haha indeed!

[@MackhackCA]

Paul, the European car makers do explain what each wire does or where it goes to in a control module in their OEM electrical wiring diagrams, for example WIS for Mercedes Benz. It’s the shitty all in one websites like the Mitchell websites you’re using for diagrams that doesn’t explain it. It’s really not a Euro car issue, but rather an American wiring diagram supplier issue. As always love your teaching.

[@jaring45]

“Isn’t troubleshooting awesome?” Yes, yes it is. Thank you.❤ This level of critical thinking is what it takes to work on todays vehicles.

[@soranghafour]

Great video , packed with lots of info and banter too , thanks for sharing and looking forward to part 3 .

[@alrifainidal]

You are an awesome teacher. I love your way to engage the students

[@Nocturnal2010]

We definitely need more mechanics. I got sick of arguing with other "mechanics" about parts changing or not knowing the difference between tapping and knocking. It was always something stupid, useless and/or dangerous. Even had a tech open a trans cause the shifter was stuck in park...of course the cable was torn and seized. I guit every shop and packed up my tools each time. Eventually opened my own 👍🏾. I've followed you for years and love the passion and knowledge, thank you.

[@jimmymakwega3872]

Paul you're damn right troubleshooting is FUN especially if you hit a nail in the head, if you dont like troubleshooting You just gave me More WORK, I LIKE THAT 😀😀😀

[@boboften9952]

Thank You Another Brilliant Presentation This IS the standard

[@federalisse1402]

Just to say you made reading the schematics easy for me. I was having a p1600 code and trace the wire back to a really bad ground. Changed ground and my truck is rolling again. Thank you truly.

[@ScannerDanner]

Awesome! Thanks for sharing

[@canotech5370]

Great video. Thanks for sharing. God bless you, Paul

[@Nypartcannon]

Love feeling like I’m in the class ! Been there before with meters ! Got to love a clamp meter as an alternative. Thanks brother

[@isalmankhan1]

Huge Surprise😍 Thanks for sharing SD😍 Love this case study👍 Stay Blessed Danner Family❤

[@Pablo_Automotive]

Another Great explanation Paul, thanks a lot.

[@renefuller9241]

And I thought I was going crazy! Thank God you guys were working on a VW. The diagrams really suck! Even the OEM ones do. It's not Mitchell or Identifix screwing up. I actually had to take one of the connectors apart (t91, the one with the Power and Ground connectors). Everything except for the Power and Grounds is wrong. Color-wise and cable-wise. 97 and 80 are supposed to be Can-H and CAN-L. There are no cables in those two holes.

[@joshgillett4188]

Its duel camshaft theres a chain on the back side running the intake cam

[@scotthayward1017]

Looking forward to the finished diagnosis and fix

[@windspoint]

Is there a part 3 I'm fascinated to see the conclusion. Keep up the good work

[@ScannerDanner]

Yes! kzbin.info/www/bejne/ooergp-mmquda8U I didn't do a good job of adding the links in the description on these. I'm so sorry. Thank you!

[@windspoint]

@@ScannerDanner thank you for sending me the link. What a mess, good example for your students

[@quaternion-pi]

Great videos and appreciate your content. Please consider more diagramming of the actual location of electrical pin connections you are showing on the multimeter or picoscope. I lose track of where you are connecting on the wiring harness and ecu as you move these connections around, especially with so many different ground connections. Thanks, great content.

[@ScannerDanner]

100% and we've gotten much better since 2016 when this was filmed. Thank you!

[@IamReadyToRock]

from Peru. Thnks Paul

[@aymenmohamed1134]

Nice job❤

[@kevinhedrick6354]

Sorry in the last video I talked about DIN diagrams, I looked it up and on those diagrams they indicate where power comes from as in terminal 30 is direct battery feed, while terminal 15 is battery + from the ignition switch. This is an area I feel SAE diagrams falls short. Also as I said brown always denotes + voltage leg of the circuit

[@jimmiehayes3566]

Hi Dan I am a big fan of yours could you please make a part 3

[@ScannerDanner]

I'll have it up this Saturday. If you are an SD Premium member, you don't have to wait, it is already there! www.scannerdanner.com/join-scannerdanner-premium.html

[@buddhaboodz]

Mr. Danner, I would like to say a HUGE thank you!! I have watch your videos to self educate me on my 2008 Audi Q7 4.2 Sline FSI’s electrical system. I bought this vehicle condemned..😂… and had faith I could fix it for less than Audi’s 😅$12K price tag fix>>>😮😢… it had no communication no start and a bag of &#%@!… but great pice I paid…Long Story short…BECAUSE OF YOU!!! THE GREAT MR. SCANNERDANNER!!! I fixed everything and it’s PERFECT!!! For approx $500 …..so I would like to say thank you so VERY MUCH! For taking the time to upload these video’s, ur Knowledge is priceless. Have a happy Fantastic Day SIR!! Gods richest Blessings to u and ur family SIR!!! BLESSINGS!!!!

[@ScannerDanner]

Awesome! Thank you

[@richardcranium5839]

i got tired of blowing the fuse in my meters i made a small inline with an atc fuse holder and go next size lower than the one in my meter. saves a lot of headaches. plus my good meter never leaves my box unless its in my hands. only have about 10 meters scattered around at any one time

[@HouseCallAutoRepair]

Now where is G103? I see misuse of a DVOM so often! Using the "OHM" setting to check grounds for continuity, it drives me nuts! Thanks Paul!

[@abdalgadermohamed5636]

thank you so much

[@garyzambrano7905]

Very nice lots of good info, maybe you can help I have a Passat TDI 2012 has a P0191 fuel pressure sensor , the dealer replaced the sensor and fuel filter code went away for few days and came back , they have not idea what to do last thing was to replace the ECM board and code came back, any suggestions I would really appreciated thank you for helping

[@ScannerDanner]

What does the the psi sensor read when measured at the sensor with a voltmeter, compared to what it reads on the same signal wire at the ECM?

[@horacioarriola2189]

Snap one is good on TSB and diagnostic

[@howlinhog]

More than a couple times I've seen shorted 5 volt reference circuits. I just knew the ECU was smoked. It's never happened yet and I don't know how it survives. I guess I just played it off to an ECU that either has very robust converter circuitry or a resistor that is also able to handle it. I'm not an electrical engineer by any means so I don't really know the answer.

[@codyarizona4925]

Great video. Personally I would have went after the pcm communication issue at the very start, as I always thought was the most important. If have fuel and no spark then I'd check the main ground for the ignition coils

[@ScannerDanner]

Just teaching through some fundamentals with my class and we were covering ignition systems in this final week of the term. So I used this opportunity to show them things we just learned, live, on an actual problem car. Not arguing at all with your assessment, just explaining why I chose this direction first

[@codyarizona4925]

@@ScannerDanner Yeah man after I left that comment I started thinking that you probably went that route for the students. I know you're very talented technician, why I enjoy watching your videos. Them kids are fortunate to have had such a good instructor.

[@ScannerDanner]

@@codyarizona4925 thanks Cody!

[@FuManchu5ltr]

Thankyou

[@ciprianbenec4091]

At min 25, the meter is set to volts. Most multimeters will not close the circuit with the lead into amps slot.

[@noahmaurano181]

The outtakes im dieing.

[@xynostasos9022]

Although you live in the US, I would like your take on the European Fiat Stilo 1.6 Marelli IAW 5NF ECU issues. Is it possible that a bad FBW electronic throttle body could damage the 5V circuitry on the ECU? Most people would just blame bad placing of the ECU on top of the engine head that would cause the ECU to get hot. But some people replaced their ECUs only for them to fail after 2 years or so again.

[@ScannerDanner]

Usually the 5v ref circuit is highly protected from shorts. Take the short away and the 5v ref returns to normal. So are you saying that the 5v ref circuit is being shorted by the TPS circuit in the throttle body?

[@xynostasos9022]

@@ScannerDanner by this I mean physically burning the 5V reference driver on the ECU side. Could a bad TPS (or anything else that works on the 5V ref, e.g. air con sensor) gradually damage the ECU by forcing it to operate outside the rated current rating?.

[@xynostasos9022]

@@ScannerDanner in my case nothing is shorted. I had some intermittent DTCs for throttle body position sensor (p1220, invalid signal) and MAP sensor (p0105) but after cleaning the TB 6pin plug with electroclean I'm file.

[@emceecoldharted2419]

Man the lack of service info when it comes to euros drives me CRAZY lol On a related note, funny thing I realized is too is that Nissan Micras don’t exist in Snap-on or Autel scanners, as prodemand has pretty much zero info on them. Super strange lol

[@fasteddie4669]

Great video, that does have two cams. just saying

[@mustafaahmedzedan9608]

You first in dignoses

[@douglash3129]

Grease pump?

[@medch4193]

Even if you provide the computer with an external ground you already have a problem in the 5v reference circuit which means that it will not run

[@nandor690]

So how is Shane doing these days? I remember him from some videos from a few years ago.

[@ScannerDanner]

This is from when he was in my class (2016), but he is doing good! Married with a couple kids and his goal is to be an instructor someday at RTC

[@gokblok]

7:16 YOOOOUUUUUUUU

[@simplemechanics246]

This was surprise...I was thinking the 1st video was just advertisement for rest of videos EDIT Around 10:53 you was bit lost. The coil should not fire on every crank rotation. Every cam yes, crank need 2 cycles. Sure, you will correct it on next seconds (I am not so far)

[@ScannerDanner]

I mean it was/is, but my plan all along was to give you guys all 3 parts here without having to sign up :-) Thanks!

[@danielmusat597]

European cars start up with 3 sparks for every power cycle. That happens as long as the engine is cold. At least this is the case for VW and Opel.

[@hpelisr]

Well scanner what is the verdict? end with ? a scuttled VW. oh Saturday. Ok.

[@ScannerDanner]

Yes sir, part 3 of 3 will be out Sat 10-22-22

[@Technical_Guruji525]

Hello sir

[@Technical_Guruji525]

Hii

[@nickayivor8432]

⏰️ 21.50pm PROFICIENT Sir ScannerDanner My teacher Thank you very much helpful information video .take care and have a great Evening with all your family around you PROFICIENT Sir ScannerDanner From Nick Ayivor from London England UK 🇬🇧

[@nickayivor8432]

Good Evening Sir ScannerDanner

[@throttlebottle5906]

24:00 and BANG goes meter fuse. 🤣 "who let the smoke out". I have killed many of them over the years. not all of them have protection and in the garbage can they go...🥳🤡

[@calebldanner]

First

[@ScannerDanner]

lol loser

[@jimmymakwega3872]

Parts changers dont belong to this channel at all, just go somewhere else.....

[@ScannerDanner]

Indeed my friend. Thank you

[@Portuguese-linguica]

Can't wait 4 part three sorry Paul . Broke can't afford it for a while.