ignition coil driver 

So cool, Dan! Love the in-depth explanation on the whiteboard of knowledge :) A couple questions:1) Since MOSFET driver is controlled by positive voltage on the gate, how do you know 100% that the ECU chip was damaged by the shorted MOSFET?2) How did you take care of the "immobilizer issue"? Please show us!3) I must admit that is a beautiful clean BMW...how does it look brand new?

Way too many shops that just scan the car and go right to replacing parts (basically guessing). Very refreshing to see a well-thought-out, methodical approach to finding the problem!

I just had a Subaru in my shop that was towed in from the dealer due to dying on the highway and not restarting. Dealer quoted him an engine at NINE THOUSAND DOLLARS!!!! I scope the coil drivers, cams and crank. The cams and crank look good. The coil drivers are all over the place. Just needed an ECM. *Superman theme plays in background*

Dan, you are the man! I have been an automotive technician for 17 years and everytime I watch one of your videos I learn something new. Thank you!

Dan, you are the man, I do wish main dealerships had the skills to trouble shoot this type of problem, their answer is to start changing modules at the customers expense without ever fixing the fault.

Nothing like binge watching all of DiagnoseDan videos. Found your channel by accident last week and was an instant subscriber. I'm very grateful for these videos and can only hope I absorb just a little bit of what you're teaching. Top notch content!

Dan, you are not just The Ultimate Professional, but a great teacher and a human being!Love each single video where you solve another mystery. It's like a detective story, but the end is always a happy one-you nail it:)Thank you for sharing your amazing knowledge with us!

I have been in the automotive repair business since 1972, this is one of the best ignition diagnostic videos. Thanks !!

Hi dan everytime i watch your videos i learn so much...ive been a mechanic for 15 years and im better because of you...you have made me find the passion again...keep up the great work

You should run your own diagnostics school you explain things very well

Dan covers it from tip to tail again. I am so great full for your concise, clear and well spoken explanations of your diagnosis and thorough understanding of the systems and components.

I really like his videos. Simple, clear no BS talking.

A another great lesson! You should teach at a school somewhere, you, sir, have a natural gift in explaining things!

Your instructional videos are still top notch and I thank you for taking the time to educate people.

Professional, exact and reliable those are the thoughts coming to my mind when I watch videos like this, however, the knowledge of the tools, components and computer's architecture requires time, patience, a lot of money but overall an excellent teacher to be reached, once again great job Dan!

WOW!!! What an amazing demonstration with the mosfet! I had no idea they were so sensitive. Your teaching technique is truly wonderful!

Hi Dan I really appreciate the time and effort you take to teach us these things. I learned some of this about 20 years ago in school and understand it better with you than it was ever taught to me. Your work is life changing as I am currently unemployed do to a workplace injury and trying to relearn a skill so that I can be gainfully employed once I get better. Just wanted to say Thank You Dan and keep up the good work.

I desire the kind of relationship you have with your test equipment I appreciate you sharing

Great video Dan. You did an awesome job explaining how mosfets work by using your heavy duty nipple clamps as a way to apply a power source. Thank you friend!

Fantastic diagnosis and explanation! Never seen anyone use a thermal imager for a misfire diagnosis. Brilliant. Thanks Dan!

I save videos that I want to watch more than one time. This mosfet transistor made it perfect. You dive deep into stuff. I know tons of great mechanics that don't know anything about a mosfet but the produce great work. They don't want to waste their brain cells or time they can be drinking beer. Lol.but not me I'm cursed, I have to know or I can't be fast and confident in my work. I've been a scanner Danner follow forever but this channel shows excellent content that gives great visual aids and there in lies my second curse. I need visual aids to have it sink deep. I just love fixing cars so it makes all the countless hours of study worthwhile. I greatly appreciate your great teaching efforts. Your videos are better than watching TV.

This is what I call a decent tutorial with all the bells and whistles demonstrated and explained and very easily understood. Job well done !!

You are becoming my favorite youtube channel

Happy Fathers day!!!!Been wrenching on my daughters car today! She is all set for her trip tomorrow! So proud of my kids!

I think your diagnosis and your explanation are the best I have ever seen

Great video, thanks for explaining everything in detail, been working on cars for many years and I never stop learning new things, thanks again!!

i watch a 3 minute ad on purpose without skipping ,since u r a great tutor.

Great video Dan! I can't believe the other shop sent the DME for repair and they told them it is working properly! I have to say you are doing an amazing job with these videos : you've got humor, knowledge and great detail! 👍👍👍 Thank you so much for the videos!

Just a thought. It's really nice to see these fancy tools in action like the scope and thermo-imager. I think it helps show what is going on. Though most of us do not have such hi end equipment. Simply mentioning that simpler equipment like thermometers or a tachometer can be used to get the same information would be useful to some.

Dan you are a teacher. I will be watching all your vids

Incredibly valuable video since it's hard to find in-depth videos that cover both the automotive diagnosis as well as the associated electronic component level circuitry. Typically it's just "The PCM is bad and here's a new one. Fixed!". Great work.

I love your teaching methods! You make everything so easy to understand. So organized and informative. There’s a lot of other excellent channels out there, but I thoroughly enjoy your videos! Thanks for all you do!

I freaking love this video Dan. A++++++ Thanks for explaining and showing us the mosfets.

Your videos and content are so good that I already put a like before seeing it because I know it is going to be GOOD. Continue your excellent work. God bless you.

HI Dan, it's amazing that the PCM even functioned at all after taking high amperage/voltage, thanks for the in depth explanation. Electronics was my favourite shop course in high school and you brought back good memories with that MOSFET, break down.

Really refreshing to see someone (like yourself) on RU-vid go into this much detail where one actually learns something, so thank you.

Great tutorial. Mostfet seem similar to relays. You apply a voltage in this case the Mostfet gate it switches on the circuit like a relay being activated Love your channel. Keep up the tech I enjoy listening to it

Special thanks to this specialized company for its error in diagnosing the ECU without which we did not see this wonderful explanation""

Dan your my new bmw go to guy you know your stuff very very knowledgeable you are my new favorite channel better than a professor from a university keep it up helping humanity evolve

Not everyone has this diagnostic ability. Exceptional!

When u diagnose it seems so easy and obvious that it seems that other shops just dont know what they are doing. But the main thing is the scope. Without a scope on modern cars you are a bit lost. I think most tech's think you just plug in a scantool and the car will fix itself.

You are pure gold! Subscribed! I have theoretical applied and know about those parts in faculty but not in practice.

FANTASTIC! Thanks Dan. I can"t understand why the dealer could not know that PCM was at fault. I hope they watched your video.

Great video on mosfets! Love the way you always prove the fix. Too bad so many crooks out there that it isn’t prudent to show how to recode the ECM. Diagnose Dan fixed it again!

absolutely great Dan, one of the top 3 channels and great bonus Euro cars

Awesome video! Loved the explanation on mosfets.

Thank you again for the wealth of information you have given to us for free, it show that you can't take anyone else diagnosis and always have to do your own..

Great tutorial! Very well described. Like how video shows everything as it's happening and why. Trouble shooting is tough enough. Culprit is usually the 1 thing overlooked. Thanks 4 posting.👍

great video .would have liked to see how you took care of the immobilizer

DAN, is the man top notch video and info as always thank you for what you do and appreciate the time you putting to show us all that. cheeeeeeeers

Another fantastic video, Dan. Most of us just install another PCM without thinking about what actually happened to the failed one. Very interesting.

Years ago i built and tested computers. We would fix them by replacing the components. Your video was very informative. Ver well explained. Very complete.

great video dan!! really well explained!! lots learnt as usual!

I wish I had your knowledge and experience, just amazing

VERY COOL DIAG! EVERY TIME I WATCH YOUR VIDEO I LEARN SOMETHING NEW.

That thermal gun application was awesome, Great video 👍👍

Awesome work sir. I have question about three wire BMW coil. We have power supply to primary coil through fuse and PCM provides ground to turn primary coil on. Why do we need ground wire on secondary coil. Isn't spark plug grounded through engine block? I hope this question make sense. Thank you again for this outstanding diagnoses and tutorial. Cheers my friend.

👌 very clever fix, now .. where's the inmobilizer fix video❓

Dan ,that was the best PCM and mosfet video I've seen to date.I learned about power supply and laptop repair in the last year.And i bought a hot air station to remove and replace cpu's and mosfets and capacitors.I do it for fun only,when you see someone do this work in front of you ,it looks easy. IT NOT,it takes some practice but more importantly it takes the ability to find and read schematics.Honda ,BMW Toyota don't put those out on the internet for people to see.Also you need to be able to micro-solder.THIS type of repair takes someone with OCD to master it...haha you made it sound to easy.I see IVAN wants to learn,he's good at fixing without parts,he can use his thermal viewer to spot the bad mosfet ,but he's going to need a whole new level of tools.haaha.Great video Dan !

Blessing I take this class at 1990 in Dominican Republic. Europeans have Good auto mechanic. Blessing my teacher and you family from NC. U.S.

Glad I bumped into you !

Great video! Thank you for time and for sharing

The only question I have is how could someone give such a great video a thumbs down? I'm glad to have discovered your channel. Cheers from Kentucky.

Thank you Dan for your great work and for the time to show us :how to diagnose. Respect.

Great job again like always A+

1:23 You should name-and-shame this "specialist" PCM testing company! Were they made aware of the cost/inconvenience they caused by saying there was nothing wrong with the module?

The demonstration was fantastic. It takes a lot of work to set that up!! I’m rewatching a lot of the old gems. I c u have the same M12 ratchet I have. Light and fast.

WOW.. Excellent Explanation Dan. All these times I can see paper or theory about mosfet and transistor. This is the first time i can see thru my real EYES. :). Best Video ever seen. You are top notch.

Awesome vid. Basically a mosfet is a form of relay. I have never come across them before in my motorcycle world. Good knowledge passed on. Thanks.

My gratitude to you Dan.... Excellent handholding all the way. Thanks

To hell with overpriced seminars ! We have DAN !! Keep up the great work mate !! :)

That FLIR was a sawy idea for sure.Great work. The immobilizer fix would be handy too😁

excellent showing . from venezuela much regards colleague!!!!!! muchiiiiisimas gracias.

The best video on RU-vid .....i have watched lots...complet and clear to the point....just subscribed

Another great DiagnoseDan video, where we see what is possible, if you have the knowledge and the right equipment.

You're an excellent teacher and a superb diagnostician. Thank you for everything.

Nice to hear that you order all parts properly. No messing about 🍺🍺

I have 4 AMG's which I'm going through electronically. Video's like this thrill me!

You are the Godfather of Diagnose. Love your Videos. Nice greetings from Germany

Good in depth explanation of the output driver from the PCM.

wow, i really love your approach to diagnosing problem.Really want more of it.

Diagnose Dan fixed it again! These videos are in a class of their own. Nice to see some quality, intellectual content still out there instead of click bait and opinion pieces.

I don't know how i ended up here, but im just glad i did, sometimes its even hard to believe that all this information is for free. Thank you soo much

Good diag and you explained mosfet very well pitty you couldn't solder another one in and repaired it you are an extremely talented technician

will done , your way of teaching and fixing the problem is very interesting , thanks a lot

Dan is so clever in understanding these problems

Bro, how can this man, teaching us in ways we can really understand get thumbed down! Those people who gave this a down vote are a bunch of knuckle heads. SMH.

Brilliant video. Love your teaching and explanations making what could be classed as complicated, understandable. Great to see what happens inside the 'black boxes'.

i miss my old 323i E36 so much, another great vid Dan.

What a pleasureable learning experience !! At last the ' Inner Sanctum' has been entered - a practical view of the wonderful world of the PCM ! I look forward to further revelations ..... Kind regards

Excellent demonstration, well done, Dan !!

Awesome your technical clarification with whiteboard and waveform explanation, and MOSFET explanation. i don't know appropriate ward except thanks of your knowledge sharing without pushing of premium video. You are great..

I subscribed. Really enjoyed the clear explanation and that neat method to c which cylinder wasn’t giving any heat

You have been really killing it with your videos. You really know your stuff and how to teach too.

Amazingly good, especially moving towards a final fix. Huge help for us diy home mechanics.

One of the Best video complemation,very informative.

Late to the party here but it really amazes me how many shops attempt to do this type of work either without a scope, or they have a tool with a built-in scope and have no idea how to use it. A dead ignition coil driver should be a trivial thing for any diagnostic technician, and your video demonstrated the process very well. It also demonstrated how such a simple diagnosis was out of reach for the other shop, yet they attempted the repair anyway. which basically means they read the misfire code and replaced the coil and plug for that cylinder. If you don't know how it works or how to test it, don't replace it!

Beautiful! This video brought a tear to my eye. Even with your thick Irish accent from Canadia I understood it perfectly. Love your videos bro!

Damn Dan...you're the greatest Technician I've ever leant from...I've learnt more from one of your videos than the years of studying autotronics. ..this video brought back memories of a e46 320i m54 engine I had, luckily for me coil number 6 just shorted down to ground and all I had to do was replace it . ..but through your video , I now know how to go further into detail. ...I thank you for educating me. ..signed : life time subscriber. ..🤘

Congratulations, you are the best master I have ever seen.