Ford "Smart Charge System" Alternator Not Charging

On many Fords the alternator has a ‘smart charge system’ that regulates the output of the alternator to ensure the battery is being charged efficiently, reducing emissions and improving performance. So let's come along with Eric O. at the SMA shop as he diagnoses this F-150 that came in with a no charge condition. Remember the alternator is controlled by the PCM which monitors certain parameters such as the engine temperature, battery temperature and electrical demand.This can sometimes be misdiagnosed as an alternator failure. Test don't guess!!
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Disclaimer:
Due to factors beyond the control of South Main Auto Repair, it cannot guarantee against unauthorized modifications of this information, or improper use of this information. South Main Auto Repair assumes no liability for property damage or injury incurred as a result of any of the information contained in this video. South Main Auto Repair 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 South Main Auto Repair, 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 South Main Auto Repair.

[@tony3552]

I promise that when I say I watch this guys full videos and it’s not the same car that I need to fix. You got to live this Guy!!! Thank you for the kind of work you do sir.

[@theadventuresofjavier8698]

Buenos Dias. I've been working on cars my whole life.30 years professionally. I always get a priceless morsel of info from every video I watch from you. your the best...as the other Eric said"Your the REAL mechanic"

[@NaberAuto]

I love the way you go through "experimenting" to show what is actually going on. I've done many alternator diagnostics over my 55 years in the business, but never knew some of the detals your Picoscope showed. I think I will be using the Picoscope more as I diagnose charging systems in my shop. Thank you for your thoroughness. Too many KZbin videos are made by dummies that don't know what they are doing.

[@bradbengtsson8984]

Wow, what an awesome video. I'm an Electrical Engineer and thoroughly enjoyed your trouble shooting process. I'm researching why my 2002 F150 is not charging and came across your video. Great stuff. I learned a lot.

[@wyattoneable]

Even for an experienced technician such as yourself, continuous learning and research is a must in today's vehicles. I'm learning this first hand, and for us old guys, it comes slow. Keep it up Eric, your videos help! The camera picked up the alternator whistling too, that was cool. I could tell by the interior that truck sees little maintenance. Thanks for spending extra time on this one, it was well worth it.

[@scotthicks8338]

My Dad taught me how to rebuild alternators and starters when we had a 1980 Pontiac Bonneville station wagon, powered by an Oldsmobile 350ci diesel. That monster ate a lot of alternators and starters. But with systems like this, those DIY days are long gone. I sell auto parts for a living, so I wanted to thank you for the information you give us. It helps me to be a better sales manager for my customers, I always want to keep them from loading up the parts shotgun and wasting their money.

[@chloeleedow7250]

I dont own this vehicle, I don't have this issue it was a random suggestion because I've watched other car videos including yours for other car issues, I still sat through the whole 40 minutes just enjoying the technical stuff I felt like I was watching myself trying to diagnose a problem using wiring diagrams, internet searches and some diagnostic tools albeit much more basic than yours. You're a great mechanic your attention to detail and OCD thoroughness is what ever customer should get from a mechanic when we pay top dollar for service. Cheers from Australia 😊🇦🇺

[@marcus3078]

I have 12 - f250 6.0s in service right now. I would rather spend the extra hours in labor to 100% fix the problem vs having to keep towing and pulling a truck out of service 2, 3, 4, 5 times before a problem actually got fixed. Thank you for taking the time to make this video AND taking the time to make sure the truck was FIXED before it left the bay..

[@jimmcdonald9618]

I am watching appreciate this to no end. I’ve just done an alternator swap on my Focus. (aka horror story) I did ok & used my crane to swing the motor and get it out. But the alternator i’d put in was making the same voltage as the one i’d just taken out 15.4V. After running the car, & watching this I went back to check & yes it had changed to the 14.2-14.3V the car needs. I had pulled a used one off a car. It had it’s rebuild stickers & was about 10 months old. I’ve only got a multimeter, a load tester BA7 to work with & was not sure on the results. Big thanks Eric ! I slept better last night.

[@bjornbjornson7192]

Wow, I just went through same thing on my 2010 edge. Your videos especially this one has helped me a lot. I don’t have all the fancy tools but you explain things really well. Thanks for all you do and keep ‘em coming!

[@davidhenley3967]

Eric I didn't know that Ford had smart charging systems. And now I have a better understanding of it. I've been doing mechanical work for nearly fifty years and with these new computer systems I'm having to learn something more every day thanks very much.

[@motorcyclesandridingfree2899]

Your a good man for doing the actual leg work for which the customer is paying for. Heck I used my Pico yesterday on a Mode door actuator and must say it was kinda neat seeing the command go to it and it's lack of reaction and was 100 percent it needed it.

[@JVerschueren]

PCM be like 'Alternator's not communicating, does the owner need to know this? -nah, it'll be fine...' :P

[@Sjackson2369]

Jan Verschueren haven’t seen a Ford with a volt meter in years! Don’t know if it’s just the super duty’s that have them at all anymore or not

[@Taillighttim26]

To be sure it's the alternator start it up let it run then take the positive lead off the battery if it stalls it's the alternator but they say you shouldn't do it on newer cars with all the computer modules but I've still done it

[@lyleallred904]

engineers should have a minimum of 2 years as a mechanic before designing cars and trucks!!!!!

[@derrickodyes1934]

engineer types cant fix a broken shoelace on a rollerskate they wont make it as mechanics for 2 days

[@GeneralRELee]

Lyle Allred maybe 4 years would be better

[@mfk12340]

Most of your engineers have done work like this before, well your mechanical and automotive engineers. It's the business guy that comes in later and says, "we nees this cheaper to maintain profit margins" "we need this within (insert impossible dimensional constraints) to meet what the graphic wants". Then on top of that there's government standards that must be maintained.

[@JohnRodriguesPhotographer]

Not with Factory tools but backyard mechanic tools. Floor jack jack stands. Big tree used for an engine hoist. Then give him some monstrosity to rebuilt the engine on

[@NitroGuyJH]

Shit dude... Most of them have already, Statistic analysis says 78 percent has had prior work in their line before becoming the engineer. So you’re left with 22 percent leaving school as an engineer WITHOUT prior experience in the field.

[@Mambre79]

Great video. I was diagnosing something similar on a Ford, battery light was on all the time. IAT sensor wasn't plugged in after changing the air filter. Now I understand why battery charging light came on. Thank you for your efforts.

[@stormwarrior5241]

You are a pleasure to listen to Sir, felt like I was standing next to you. Well done, very thorough. Hope you got a beer on the way home!

[@habatroll4831]

Eric thank you for taking the time to shoot that video. I am a big fan of your channel. I agree better to test than to guess. Having a good reputation for quality work is what keeps you in business. Have a good one.

[@paulkirkland1535]

Gary Habat:I second that, my thoughts exactly.

[@edgatternig9729]

Your timing is perfect Eric. My alternator is done on my 2002 f250 and this classroom video comes at the perfect time. Thank you sir for the late night lesson 👍

[@hawaiianf1504]

This is the 4th time I've watched this video because there is so much information to delve into. -- It's not just the procedural steps that intrigue me, it's the way Eric interprets and conveys the information all the while mixing his working knowledge with his experience for our benefits. -- For you and me, Eric manages to break it down into palatable sectional art. Eric is the perfect master artist to expand our knowledge and toolboxes. Every time I watch this, I get something I missed from the previous viewing. -- Thank's Buddah - again you dun great!

[@marklokken1378]

Thx Eric. I watch all your videos. I’m a shop owner and you sir are very gifted

[@IntuCars]

I absolutely loved this. I learned so much. Thank you Eric

[@fielding68]

Advanced mechanics and electronics, didn't understand much of it, but was fascinated. Thank you.

[@guillermogarcia2078]

This happened to me while driving along on the highway, all my gages turned off on my 2001econoline f250 van equipped with a handicapped ramp. I had never seen anything like that ever happened to me knowing quite a bit about mechanics being a mechanic since about the 80s N early 90s. I'm paralyzed now so I can't do what I use too ( mechanical work ). nevertheless it turned out to be the alternator point is that it gave me no warning except the gages just stopped working til a mechanic came to the highway, put a computer on it and found out it wasn't charging. Oh and not even did the charging meter warned me that the battery wasn't being charged! like I said, everything just turned off. after replacing the alternator everything started working again. Thanks for your videos cause they show us alot.

[@billmck12345]

thanks to this video I was able to get through the 2012 f150 with the battery light with a p0625. found the fuse-able link for the 'gensen' not completely blown...but I saw it dropping to 0 volts...thanks eric!!

[@idontreallycare5743]

Eric, The way I heard it several years ago is.......GEN_COM pulsing 1 pulse every 5 seconds is the PCM telling the alternator "no change in voltage set point. Keep doing what you are doing." Multiple pulses is the PCM commanding a different set point. When you start the engine you can watch the GEN_COM duty cycle ramp up to the target. Then you see the single pulses every 5 seconds begin and continue until something needs to change due to electrical load, RPM etc. This may not be 100% correct but engineers don't tell us everything about what they are really doing.

[@williamvaughn2938]

This is correct, but it's actually talking about the voltage of the battery itself. So, it shuts down other sensors to try and force the battery into a charging state, but since there is a lack of communication elsewhere, the alternator is not engaging correctly. In other words, I bet this truck charged ok via the Highway, or after the engine comes to operating temperature :-P. Thanks a lot for your input here. I know it's been 2 years.

[@josephgrossjr9356]

Hi there Mr O, thanks for your many great videos ! I'm a mechanic in Baltimore, MD. I enjoy watching your videos and I have learned a lot. Again Thank You!

[@OneAuto]

Yep.. Same crazy idea over here! Although most of the later Fords I've seen have gone back to the single wire to the PCM

[@BuzzLOLOL]

Thanks for your patient, in depth videos...

[@rodx5571]

Whether or not its relevant to the job you are doing, Its relevant to the job i am doing, and i appreciate that greatly. I have one that charges and quits charging, Alternator replaced, battery replaced. So this vid greatly helps in my impending diagnosis. EDIT: just for clarification, i did not replace either, the customer made assumptions and did this before contacting me. I AM NOT a parts changer. I dont have a fancy a$$ pico, (yes i am jealous, but not in a malevolent way) however my Vantage Pro or my Autel MP408 will do nicely.

[@Fireship1]

Great troubleshooting and fix Eric!

[@denniswilkinson1118]

WOW!! That's what I call an in depth video, but you lost me at the bakery, but still a great video. Thanks Eric.

[@arcadeair95]

Excellent video, Eric. I have an 03 focus sitting in the driveway right now as it will not charge... same as this truck, no batt light and the gages wigged out a bit. Not having a scope yet, I will unplug the connector and see if it will default charge. I already checked the 175 amp fusible link on the charge line and it's good. Great video

[@1954BJohn]

An honest mechanic - you sure are a rare entity Eric.

[@kyhomegarage3430]

I have to admit I would struggle a lot to understand this type of charging system. Thank you so much this will help somebody for sure. You are awesome. Cheers.

[@JohnRodriguesPhotographer]

Essentially the charging system adapts to the temperatures in the battery and the ambient temperatures. These things can affect the rate at which a battery can charge. My battery is low you can charge it fast up to about 70 or 80% depending on conditions. After that it charges much slower. It is the nature of what acid batteries. This charging system attached to make the charge itself more efficient if you're trying to jam volts into a battery that we can't take it because the battery itself is 2 warm War the ambient temperatures to armor both these things are governed by physics. So if you're trying to throw voltage at a battery that can't take it and you're just wasting fuel. Not sure I'm qualified to judge whether or not the system could have been done differently but I do know that lead acid batteries require some monitoring in large systems to ensure proper charging and not boiling the acid in the battery. Boiling your battery is bad because it gives off excessive amounts of hydrogen and oxygen.

[@jth1699]

Nice informative video - if unplugging the controls wires on the alternator don't set a code then swapping it out for a single wire Delco wouldn't be a problem... I have been a generator man for about 30 years and as far as complexability goes - this ford system is not that bad at all - to test the alt just unplug it and rev the engine and see if the voltage comes up - if not you know u need at least an alternator - for you guys that were asking why you have to rev the engine it is because the alternator has to build a certain voltage to turn on the regulator - this turn on voltage is caused by what is referred to as residual voltage . The residual voltage is caused by the leftover magnetism in the steel of the field coil. Once the residual is high enough the regulator will use it to create the input power for the voltage regulator which will then supply the field current to the rotating field to complete building the voltage to the required level. I haven't seen anything on how this thing works but I'm pretty sure this won't miss the mark very far - when the computer communicates with the alternator what it is doing is first controlling what is referred to as a field flashing circuit - this circuit makes the alternator build voltage without having to rev the engine - what it probably does is take power from the battery sensing lead and feed it into the regulator - then the PCM just senses the battery voltage - engine speed - air temp - throttle position and whatever else some brain dead moron engineer could dream up to arrive at some desired battery voltage - the results of that PCM subroutine determines the signal sent to the voltage regulator to either raise or lower the field voltage which result in the rise or fall of the alternator output. I noticed that when the throttle went wide open the charging current was cut to 50% that is probably a system to allow for more horsepower to the wheels - logic being you need all the horsepower available otherwise you wouldn't have your foot stuck through the radiator... The basic logic behind all the engineering changes to ford and the rest of the car manufactures rests with two trains of thought - the first is simple - if an engineer told his boss that whatever system he was responsible for was good and needed no redesign or changes he would be laid off the next week simple as that - the other train of thought and what all the engineers blame is government regulations - and government has practly regulated automobiles to such a point that the cost of ownership is getting more than most folks can afford.. I think it would be fantastic if all the auto dealers would send notice to the Feds that they would all shut down on a date certain because they could not build a car that could pass emissions - the car companies would tell the Feds they would close down layoff all assembly line workers and just supply replacement parts for the existing models ... And all the laid off workers would meet any boat that tried to import into America and burn every car unloaded... I bet the epa would back off of some of their BS then.... Keep up the good work Eric

[@minnesconsinprepping7856]

You are a fantastic mechanic, and you obviously know your stuff. I would take my truck to you any day. I just wish you had done one more thing to make sure that it was indeed a faulty alternator. You should have disconnected the OLD alternator from the (dumb) smart charging system to see if was indeed bad. The reason I say that, besides the obvious, is that there's talk out there on Ford forums, that the computer learns bad behavior, and recognizes it as being normal. I just put a new battery in my 08 Lincoln Mark LT, and now it's throwing a code for the charging system. It started doing that the minute I started the truck after I put the NEW battery in. It NEVER did it before while the OLD battery was in it. It would be absolutely amazing to me, that at the very instant my old battery was completely dead, the alternator crapped out as well. I know it was the battery that was bad, because it would be dead in the morning, I'd jump it quick, and I could drive around all day with the AC on, the radio on, drive at night with the lights on, and it would ruin just fine, and it would also start up every time I started it that same day.....then.....it'd be dead again in the morning. So, CLEARLY, the alternator was maintaining a certain level of charge in the OLD battery. The battery would just go dead overnight from the power draw from background devices.....alarm, radio memory, etc..... Anyway....I looked that symptom up in the Ford forums, and found that this is a very common thing actually. So, I just figured I'd let it run for a couple days and see what happened. I just kept hitting the reset button on my dash every time the battery light came on, and the monitor said to check the charging system. I noticed today, that indeed, my battery was getting low on the gauge. I was driving by pep Boys, so I whipped in to see if they could test my alternator quick. The guy did the tests, and showed me that my battery voltage was 10.4....and that my battery was junk. lol Well.....no duh my battery voltage is low.....I told him that my battery was about dead. But....at any rate, we tested the voltage while running, and, it didn't go up at all...so.....clearly the alternator isn't charging the battery either. I doubt the battery is junk...it's just currently dead.... But here's the issue. While my OLD battery WAS dead, and was obviously dying for a while, the truck kept running fine, I think the computer just learned that low voltage as being normal, and so now it won't charge the new battery. You follow? The old battery was probably only running at about 11-11.5 volts, so the computer interpreted that as being normal, and now it won't charge the new battery past that, and actually lets it drop even further. I'm going to what you did, and unhook the alternator from the (dumb) smart charging system, and see if it starts charging. If it doesn't, obviously the alternator is bad then, but, I'm betting it'll charge it. It looks like a newer alternator on the engine. I just bought the truck in April, and all this stuff going on is telling me that the previous owner probably had similar issues. Just wanted to give you something else to think about. Thanks for all your information!!

[@ingejeppesen1358]

Hi Eric. I see this all the time. Have never seen a battery light on with KOER. It is not any fun when your headlights fail in the night in the middle of a turn. We have reported it to Ford and they don't seem to understand it them selves. Great vid! worth the time making AND watching.

[@JHC1official]

Great video! Thank you Eric O.

[@HayesMobileAutoRepair]

great vid...thank you... im learning this system too...so thanks for your video.. love how you took the humble route on this vid.... no mechanic know every danm thang attitude.. its a constant learning process...awesome dude!!! hayes mobile auto repair

[@shaneharrison4775]

It get you more knowledge on the workings of the system and helps to know what to look for

[@jimzivny1554]

Hope you get home before you fall asleep. I enjoy technology but I think in some cases the manufacturer's have gone too far. You don't need to build a nuclear reactor to light a cigarette, a charging system doesn't need to be so complicated. Just my opinion.

[@thecosmy1]

Haha ! Awesome ! I JUST learned about Alternator in university about a week ago ! And I remember exactly what my teacher said about this smart charging system ( assuming we are talking about the same thing ) ! Its awesome to see it in practice what you learn in university. THanks for your videos !

[@northfloridafungi9336]

What did he say?

[@thecosmy1]

@@northfloridafungi9336 i forgot 😅

[@northfloridafungi9336]

@@thecosmy1 totally relatable. I start my senior year in exactly one week from now and I can't remember much of the 3 that got me here, I just remember there was a lot of writing, and college algebra made me cry and question my life

[@llessibm]

Thanks for this - I've been searching trying to find more detail on the smart charging system and even though you didn't ultimately answer the question about the battery light you've shown me enough to understand where my fault might be coming from - thanks for that

[@dangerousfreedom4965]

More info on your problem?

[@MrRChitty]

Very helpful and complete!

[@terrygaddy7768]

Utterly awesome Eric. Hope you saved that waveform to Pico's waveform library. I'll be looking for it. You earned your place on my Teachers Hall of Fame Wall a long rime ago. This post just reaffirms why you belong there.

[@tappedurmom9739]

Thank you. You helped me with my own problem so much. Only thing is the newer 2016 ford's will throw every code possible except the battery light when the alt goes bad lol

[@darylphipps5262]

each video seems like good teaching tool. Many thanks!

[@kennypatrol2zero616]

Just Going through your library of videos, and the ford charging is,,,, well,, "just excellent", you looked really tired, this one helps everyone, well done buddy, keep up the good work, cheers KENNY

[@madmotorrepair1748]

Really enjoyed this video! always learning​ something from you! thanks alot!

[@robertlackey9742]

Dear Eric O. Your videos have helped me more on my 2010 crown vic police interceptor charging system than the two days at the dealership. I'm disabled because of being a mechanic, Injury while doing marine work. So I'm broke, a third of my check goes to child support Otherwise I'd gladly send you a donation. Put it to you this way. This is the first car I've had in 6 years. But I build boats ,or did, worked for Rand McNeilous. On cement trucks ,and have 5q8 months electronics tech school Of course that was 30 years ago You've seen how thi us have changed. I'd trade ten crown vic police interceptor cars for my 73 satellite sport big block. Those days are gone. And the joy of automechanics went with my injury. But I can't even get the dealership to be truthful with me. It's funny cause when you and I have no ed on so to speak, cars will be all electric , and mostly drive themselves Lol or sad? a bit of both perhaps. Anyway, thank you for the knowledge. Most unselfish of you. Peace

[@jimmorton3009]

GREAT VIDEO, Eric. Thank You. Thumbs UP

[@jeffpagnutti]

I didn't really want to dive into a 40 min video, but I'm really glad I did. That was far more interesting and informative than Aquaman.

[@charlesmiller5078]

Your so relaxed while talking to the camera, was it a strange feeling when you first started doing videos and watching yourself. Did you do alot of family videos around the house before the channel. I guess you just have to remember when your talking to the camera, your actually talking to thousands of people. No pressure :)

[@GrahamReid34]

Bmw has the same system, most guys just by pass it saves any hassles, thanks for making my fri with another sma video.

[@longdong3889]

How did you bypass it?

[@iduimovic]

Great case study for your friend Ivan.

[@ryanwhelpley1339]

Your video was exactly what I was having problems with with my six GEN alternator charging system in my Ford mustang 200 4 oh I’ve been trying to deal with this for like three days I’m not a mechanic I don’t have a mechanic shop but I am mechanically claimed and I tried everything I’ve researched it all and it kept just not charging so I’m gonna go try what you just did and I’ll re-comment back in the comments but so far you’re a freaking genius thanks

[@lavasnake]

i've got the 04 Mach 1, 6 month old alternator and i cant find any info on the middle wire on the alternator pigtail, i get 12v to the 2 outside ones, nothing on themiddle one Did you find a fix?

[@vipervette03]

Erick. You did the right thing by all the testing. But I still can't understand why the change light will not come on. If you find out please let us know. Thank you again for all the good information.

[@jeremyanthony9300]

your videos are always awesome. I love them.

[@MrONEHORSEFLY]

Well, it was an interesting analysis, but since I don't have Eric's test equipment and never will, I would have just changed the alternator myself and hoped for the best. The alternator is one of the easiest peripherals there is left to change on new vehicles anymore. "If I can do it, you can do it".

[@AP9311]

also Eric O, I've set up my pledge on Patreon to you, SMA for monthly payments :) love your videos again!

[@mikefedele4521]

I had a very similar issue in a Lincoln . In that case it needed an ecu we ended up waiting weeks for it. Cool video very surprising it wouldn't throw a light?

[@yhird]

Really great diagnosis.

[@billymcclanahan1794]

Sir, you are something else, I watched your Nissan vid on the car going into limp mode n now this one, I know you have done this a long time but remember so many things you know usually goes bad for the info your getting from the car on your monitor and I know you work on so many different vehicles but you seem to remember so many past vehicles issues lol, my hats off to you bub n keep up the good work at the shop and vids, happy thanksgiving to you and your family, and yes I know it’s an older vid lol

[@marcwingfield1646]

great info see this regularly on Mondeo's in the UK

[@baxrok2.]

Nice work. Thanks for educating us. I've heard about these systems but only seen the GMs being diagnosed. Thanks!

[@josephtucci3666]

Well done Eric Simple math really $10,000 worth of equipment= one repaired alt.! You just gotta love this job! Best of luck friend.

[@Bible777193]

Well done, a good video, thorough!

[@rvsteve583]

we must get a follow up, life depends on it.....................never disappointed when i come here, always learn something.

[@parsedout2576]

3 seconds into the video, automatic thumbs up!

[@hawaiianf1504]

Really Great Video!! You ain't crazy one iota. As far as I'm concerned, the ones who disagree will never learn the who, what where and why of anything. They will only settle for the "toss in a new part" without being 100% sure why it's the right thing to do. Further more, I will bet an rootbeer and ice cream float that they'll pass onto the customer all the costs for unnecessarily ordered parts.

[@geraldsanford2411]

I agree 100%

[@hawaiianf1504]

Thanks! I get so much more when I understand what I'm looking at and working with. I'm sure that is the same for many others. It's always best to learn how to fix something than it is to run in, drop a load and dart off into the cloud. Oh wait, I was talking about fixing auto's not toilets. Sure glad I used the letter "d" and not "f". After all, this is a family channel. Eric will always teach us What to do with the Why explained and the How to do it if we are willing to watch, listen and apply. That's when we ask those relative questions to everyone in the channel and are quickly guided by the best in the field. And when I don't know what questions to ask - I simply re-watch the video and the answers abound. When they don't get answered we almost always learn how to ask our questions in better ways. Thanks Again Gerald!

[@sebry25ify]

another treat from SMA.

[@bigrockk2980]

Thanks man, great video. I learned something once again :)

[@stevecorey3399]

Very thorough diagnosis sir.

[@AP9311]

Eric O, great video!! great diagnosis! also I wanted to mention that the last few videos of watched videos didn't have captions on it. So I wanted to tell you if you could include them in the video please? So I can read what you said, thanks in advance! keep them videos coming :)

[@cjmazdatech]

Great video and info. When I worked at Kia I found they also don't have the battery light come on when it's not charging. Have had them come in barely running at 10 volts after a boost and no light.

[@zombietherapy1759]

i'd be interested to see if a diode was bad in the alternator, back-feeding the system. Does your scope give a diode pattern? Great video.

[@mini-bandbycunningham482]

Excellent help! Thank you. I am troubleshooting problem that ramps up then shorts and drains the battery quickly. Still digging into the cause though. Thanks man! We'll see... 87% 😆 maybe...

[@michaeljackson4317]

Glad u did this because I checked mine the same way

[@matthewstewart2549]

very informative video, put a new alternator on today and tested it at 14.1 V, post test drive it dipped to 13.6, and then 13v after letting it idle for a bit. unplugged the coms from the alternator and its charging at 14.1-14.2, battery light has also popped up. bit of a loss right now, either the alternator regulator has crapped out, or the PCM system is restricting charge not really sure.

[@harrylafountain3569]

Great video....learned alot on that one💪💪💪

[@rrcoster]

Awesome work from nothing but the finest Eric.O as Ford sure isn't very Smart on the charging system lol. You notice right away that its odd that the battery light wasn't on since it wasn't charging and instead of ignoring it and just taking the simplest guess by putting a new alternator on it you diagnosed the problem to make sure it was that kudos. Id rather see a mechanic figure out what the problem is and not just throw parts at a vehicle as a guess.

[@billyyoder8171]

Eric, Remy Power Products youtube channel does a good explanation of the Ford charging systems. The GENCOM duty cycle can go silent when no change in charging status is needed. Also, the regulator supplies the voltage on the GENCOM line and the PCM toggles it to ground to create the duty cycle signal command. The PCM supplies the voltage on the GENMON line to the regulator. The regulator GENMON will toggle the signal voltage to ground to signal the PCM the charging status. Remy also has good explanation of GM and Hyundai charging systems on their youtube channel.

[@treborhi]

Watching it now. Good explanation.

[@ouch1011]

I was just about to say this. The PCM will communicate when it wants to change the desired charging voltage OR it will send the same signal once every 5 seconds or so if it DOESN'T change the desired charging voltage. It does the 5 second pulses so that the alternator can be sure that there isn't a loss of communication and go to fail safe mode. This can be verified by watching the scan tool data. It shows 0% gencom on the scan tool when the desired charging voltage stays the same, but shows changing gencom when the desired voltage changes. I suspect that the 0% display on your scan tool for gencom when it isn't continuously communicating is a glitch with the autel, but I'd also guess that if the autel had a much faster refresh rate, you would see it briefly show the correct gencom duty cycle every time it transmits every 5 seconds. I am fairly certain the IDS is programmed to show the last gencom that the pcm transmitted rather than a literal display of what it currently transmitting on gencom. Also, a quick note on the alternator fail-safe or "default" mode if it doesn't get any transmission from the PCM. It will only start charging at its preset voltage in the absence of data from the PCM once the alternator rotor speed passes a certain threshold. Its different for every car since the pulley sizes are different, but generally speaking it should start charging and continue to charge if you rev the engine to around 3000rpm.

[@TheOzthewiz]

Hi Eric! Love your videos and as a retired Electonics Tech, I am impressed by your electronics knowledge along with your excellent mechanic skills. I really am getting tired of some of these KZbin mechanics that call any car electrical problem a "short",ie, some Scotty guy. I have a question regarding the BMS (battery management system) that is used in a 2013 Focus. I recently purchased a Focus with 56k on the clock. The issue I am having is that the body control module is "off loading " some of the non-essential electrical items such as ; the media center, the wipers and other items occasionally while the ignition switch is in the "accessory" position. Everything works while the car is in the "ignition" position and/or engine running except I get low batt at times on the center display panel. As I understand it, the Ford BMS has a "battery aging" that the computer checks. When the battery is replaced, the body control module MUST be reset,otherwise the computer will still "think" the OLD battery is in the vehicle and will continue to "turn off" some systems. My question is, how can I reset the BCM without going to the dealer and paying $150 because I DON'T have a Ford multi- thousand dollar scan tool. Also, what is your take on disconnecting the sense wire going to the NEG side of the battery. Will this throw a "light" and put me in a worse position like screwing up the electrical sysytem? Sorry for being so long winded, but I figure if anyone understands this funky set up , you're THE MAN!

[@robertlackey9742]

Thank you for the knowledge. Your video on the crown vic police interceptor was helpful. I have a 2010. New alternator. New battery. Understand the smart system thanks to you. A little scared to fire it up unplugged. 300$ alternator. But I'll try it. I have no scope to check for the com or mom side of the system but I'm in upstate New York. The salt damage to all co hectors is horrible. Was thinking about replacing the pcm. Read that if the charge light fails it'll cause a no charge pro lem. As with you, no falt lights or check engine lights on. Only batt light appreciate any ideas. Thanks Robert Lackey

[@bobmoy3406]

We the 'People' Thank You for all your effort in producing these videos.

[@paulkirkland1535]

Bob Moy;I think the same way too​.

[@spelunkerd]

To simplify diagnosis in this kind of system it would be convenient to be able to disconnect the alternator from the system and test it on the bench, independent of their complicated communication system on the car. The old 'full field' charging systems did just that, in a much simpler format. I am surprised Ford didn't think of designing the program around that principle. Did you ever decide how this alternator failed, was it a software problem inside the device, a voltage regulator issue, or the alternator charging system itself?

[@AntonioClaudioMichael]

Running the com line down and high and no change Intriguing definitely looks like the Entire system is functional looks like the alternator has gone bad Eric O good Video @SouthMainAutoRepairLLC

[@TheSourHours]

A famous ass kicker once said "Simplicity is the key to brilliance." I guess that does not apply in this field at all.

[@sierrawhiskey5155]

Artificial illetigence is just round the corner, together with a "do next" flow chart it'll all come good

[@WilliamBush1967]

You think that's bad what he didn't tell you is even worse! If the battery light burns out the system will not charge. Now isn't that just brilliant Ford leaves people stranded on the road because your check battery light burned out your car isn't charging and you don't notice till the thing is acting up and you are low on voltage.

[@eric_seguin]

@@WilliamBush1967 I was wondering if the battery light was working at key on, engine off.

[@muckley2012]

Great video thanks for your time ! I recently diagnosed a BMW 525i with a low charge condition , checked charge rate at battery found it too low , checked again at B+ post on the alternator and it too was low , case ground ok as well. Scoped the single LIN line into the alternator and found the PCM command signal present and intact. Was seconds away from calling an alternator when the PAS pulley caught my eye , it didn't seem to be turning at the correct speed from what I could hear of the engine speed. Got a colleague to rev up the engine and the aux belt didn't change speed with the engine rpm , it stayed approx 300rpm . Took the belt off and found that the crank pulley had delaminated and was acting like a slipper clutch, the more load on the belt the more it slipped. The centre of the pulley could spin independently of the outside. It pays to do the correct checks I guess , but I've never seen that happen before in my case just guessing at the alternator would have dropped me in the proverbial. Thanks again !

[@Cheepchipsable]

Expect the unexpected! There is a DiagnoseDan video where the door handle stops a BMW from running.

[@davidscharringhausen8949]

very good video. You tested edery thing available. you got it right , the owner didn't buy unneeded parts. The battery light not coming on would require another round of test's. Maybe a computer reprogram ,Good job.

[@zxtenn]

Bottom line is you made the RIGHT call, you sure know your job Eric, that's why I try to do all my own work on my Jeep GC, even with my limited electrical knowledge at least I am not paying someone for nothing. Last weekend I installed the Bosch 4 hole injectors and did all 8 in under 2 hours, got all 8 on ebay for 70.00 -- Seems any NASA level creation is used now to save .000001 of a gallon regardless of long term reliability however I remember when a battery would be almost junk after 2-3 years and water pumps lasted maybe 50 K. I just bought a 2017 Sonata 6 speed manual with their 'Allison' engine and the gas mileage is AMAZING, I get about 35 mpg and my former 2009 Accent with a 1.6 manual barely got 30-- From what I have seen of Ford lately I decided another H would be a smarter choice, I have had 4 all with excellent service

[@2009mechanic]

Have you made a video yet of the newer GM charging systems with the current transformer on the negative cable and what interesting things you can run into with bad grounds and also what interesting things you'll run into when adding an auxiliary battery and/or adding aftermarket high current accessories to the electrical system like off road LED light bars , high end stereos ,winches ,etc.

[@waynegibson8395]

Always enjoy the method to your madness...even when I get completely lost. Maybe dumb question...can one just unplug the "control" feeds and use as an old school setup?

[@Drmcunningham]

Good one Mr. O

[@a1972ss]

Great vid Eric!, I have struggled with this system in the past, I learned a lot. .....was that a OEM Ford alternator or aftermarket? Just had a Mazda with similar setup, it did not like aftermarket alternator, dealer part was back ordered, three weeks later every one is happy with OE unit.

[@Nymi5]

Great video again, a flood of info again :)

[@63256325N]

Thanks for the video.

[@joshmartindill8074]

Been chasing gremlins in a 07 mustang that has a 05 motor in it and this really helped

[@mph5896]

That setup should turn the battery light on after about 20 sec of running, and also set a code for the gen terminal. I know this because I had a 2006 Expedition in, had a brand new alternator on it and was charging at the 13.7 volts. The "new" alternator had the incorrect regulator on it and was in default mode like you showed. A replacement alternator with the correct regulator made the pcm happy.

[@lgregg2478]

I was reviewing your video after watching Advanced Level Auto...with another Eric as he was dealing with another ford with alternator issues, it was interesting that the system did not trigger any immediate warning about a bad charging issue. Did you gain any insight about how Ford triggers the warning light?