Ford "Smart Charge System" Alternator Not Charging 

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.

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"

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 RU-vid videos are made by dummies that don't know what they are doing.

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.

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.

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..

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.

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 😊🇦🇺

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

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.

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!

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

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!

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.

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.

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!

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.

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.

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!!

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

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.

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

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.

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.

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.

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!!

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.

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 👍

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

Okay, time for a rant. The manufacturers, in search of operating "efficiency" don't consider overall cost of ownership. I learned that on newer BMWs and MINI's (which I have) you have to program the ECM when you get a new battery. The dealer charges $148 for this service. So on top of the cost of a new battery ($160 for the only battery that will fit a MINI) you have this charge. Whatever savings you might possibly get from a more efficient alternator are completely lost at battery change time. All to meet Government CAFE standards.

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 !

Very intriguing issue Eric O looks like The Generator is no linger communicating with the Pcm and when the pcm seems no communication back it shuts the communication down @SouthMainAutoRepairLLC

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

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".

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 :)

Too much technology for such a simple operation

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

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.

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

Yeah, makes sense. It sets the generator output to max and leaves it, just periodically setting it again. Then after the engine goes back to idle it looks like it wants to check and see if the battery is charged yet, or if it needs full charging current again, so it lowers the output to see if the battery holds the voltage high or drops again. The generator doesn't need to be loading the engine when idling if the battery is fully charged. Also, the indicator light did come on! 24:41 your scan tool changed "Generator Fault Indicator Light" from "Off" to "On" while you were revving the engine.

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

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

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

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.

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.

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.

I've just learned all about these systems when figuring out a dead battery on my Ford Focus diesel. Was waiting for you to do the hillbilly alternator check and pull the 3 pin plug and check for the 13.8v. The system (on my application anyway) also references the coolant temp sensor and delays charging on a cold start to reduce emissions. Takes a couple of minutes before the charging ramps up. I show this in a basic way on the battery vid i just did.

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 !

Conclusion: When Erik O says, "Interesting" he really means, "WTF?"

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

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!

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.

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

Eric great video and diagnostic. I will add that the Alternator also shuts down during acceleration and varies on demand of the engine for better fuel economy. It will also increase charge when the engine is under deceleration to economize fuel efficiency by drawing power to charge the battery.

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

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

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

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

I'm just a DIYer but thanks for reminding me why I'm keeping my 2003 F-150 rather than going newer. Broken spark plugs, overcomplicated electronics, VCT problems, man I sure don't want a newer truck. I actually bought a 2011 F150 new, drove it for 4 years and went back to the 97-03 gen. Like them much better. Cheaper, easier to fix, more reliable, etc.

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

the intent of the system isnt bad, its a pretty sweet design that is going to get more service time from batteries because of better charging strategies and more life from an alternator because its not always charging, not to mention a little bump in fuel efficiency.

According to Nissan's engineers, newer Nissan charging systems can run as low as 12.2v and be considered normal operating condition of the charging system. Awesome smart charging system that they have.

I really liked the fact that you showed you did not have the answer. if I lived closer I would trust my truck to you simply based on your honesty. thanks for the video. I take my hat off to you... now go get some sleep

Another valid point for this video is the battery type. Smart charging systems must use a Silver calcium battery and not a basic lead acid one. Silver calcium can take the boosted voltages that the PCM demands whereas the lead acid ones can't. The constant demand for high volts will kill the lead acid battery.

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.

The alternator is shunting charge and not sending a signal of failure due to it not meeting the signal for it to send a failure to the IPC to indicate a failure. The alternator is providing just enough charge under idle to charge, but not enough charge under load. The under load voltage is sufficient to not trip the IPC to illuminate the battery light. Essentially the diode has partially failed and is essentially "shunting charge" . The Ford dash and lights all react in strange manners when the battery charge gets low and creates havoc with the electronics. I went through this with a 2011 Ford Edge limited alternator. The alternators are not able to be rebuild or repaired and it must be replaced. Highly recommend a new OEM alternator. The Ford Edge will display "battery Saver" warnings with low battery's but this does not point to the alternator. Load testing must be performed and can be tricky to detect as it sometimes can be very intermittent or barely noticeable. Eric a Ford Edge alternator is a real PITA to change as you have to remove the fan assembly, tire, wheel well cover etc and work from bottom and top to remove the alternator and you have to work the alternator to from the passenger side to the drivers side to remove it. Then reverse the process.

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.

that's why I sold my shop, customer doesn't understand the lost time, either way the shop pay for it.

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

This was a really informative video describing the "smart" charge. I have a stupid 06 Escape doing an overcharge condition. Had mechanic swap the alternator since you get to pull the axle and unhook a motor mount to get to it, and all was good for 2 days. Then went back to same condition. Saw it was controlled by ECM, so I replaced that and got it reprogrammed. Looked good in driveway. Only have Forscan, no real scope to mon GenCom and GenMon. Even if I did, the connection is too buried on that stupid Escape to get to it. I can monitor the ECM versions of the signal and they look good after disconnecting the battery. Don't see every 5 sec GenCom pulse, but that is probably due to Foscan ECM sampling rate and they are short (battery is fully charged). Looked good in driveway for 15 min until you drive for 10 min. Then all of a sudden, ECM reports no signal from GenMon, and alternator jumps to 17V or so using multimeter on battery... Disconnect battery for 5 min, and it goes back to normal for another cycle. Alternator probably passes bench test since it works at first, but something internal in the alternator/regulator? I'm at a loss.

I love my one wire GM alternators.

Thanks for your patient, in depth videos...

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?

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.

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 RU-vid 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!

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.

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

The PCM sends out PWM waveforms when a new setpoint is commanded. Otherwise its every 5 seconds. The sparodic PWM outputs are just to maintain that threshold.

From working with TV remote controls, the button pushes usually send a code to the infrared emitter and if you hold the button down continuously, a "repeat previous command" code is sent instead of resending the the entire code again. You may be seeing the initial GEN COM code being sent followed by a "2 blip, 5 second repeat code" (just guessing). It follows that when revving the engine the conditions change so it sends a new GEN COM directive and then follows with a "repeat" code until conditions change again. I watched your video because I have an 07 Ford Focus and changed the alternator and had output for a short time until installing the alternator cover which squishes the wires. I lost the output at that point. I will have to check continuity in the GEN COM and GEN MON lines and make sure I have continuity in those. Like you, I had no battery warning light. I saw another Ford alternator video where there was lack of continuity in the command line and by replacing the wire, the output came back. Thanks for taking the time to make such a great video.

I think Ford was trying to do what Honda had for some of their earlier econobox vehicles, except that Ford comes up with the idea that more switching in the "Com" packet indicates Less output while less switching in the "Com" packet indicates More output. That leaves the final output control to the voltage regulator which is exactly how a regular generator in a "pre-smart" Charging System works! It looks like the engineer started to figure this out, loss his train of thought, threw up his hands in disgust and said "Let's go with this!" It's only partially figured out! 1996 Chevy Cavalier 4 cylinder had this system AND IT WORKED GREAT! You could test the charge system with the Tech 2 and that was great! Dodge and Jeep from 1997 both had computer controlled generators from the computer, nothing in the generator, AND THAT WORKED! ! FORD..........well the engineer had a rough night or a wet dream? My apologies for the rant. Ya, I've seen and delt with this sucky system before ! ! ! You still put out a "Great Video!"

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?

Take a look at the ground wire down by the stater on the bell housing that’s where my trouble was on my explorer 2006 it was broke off which caused the alt to short out

Anyone who visits to hang out in a garage quickly finds that they’ve been baited and switched into a classroom.

3 seconds into the video, automatic thumbs up!

Hi Eric! Although more than a year passed since you made this video, I only saw it now and have 2 questions bugging me: 1. Don't you guys repair the alternators for the more common faults? (bearings, voltage regulator, diodes, brushes) 2. Would the old alternator work if the "smart" plug was undone? Could it be just the "smart" part of it bad and it still would work as "dumb"?

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

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

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

This system reminds me of Homer, when he says I am so smart, I am so smart, then spells it s m r t.

I've seen it many times. By the time they perfect this system, it will be obsolete. By then there will be another great engineering marvel(on paper), that will be another failure. Is this the way technology evolves.

I have sat and watched this three times now... The reason being that some Jaguar models, notably the S type which is loosely based on a Lincoln LS I believe have a similar smart charging system. And in the UK it struggles to fully charge the newer batteries available on the market, in fact some of the batteries available these days it really struggles to charge to more than 80% of capacity. The Calcium type batteries need 14.4V to charge them, the S type in 3 litre form, and the 4 litre version (which I own) use the smart charge system to maintain these batteries and seem to "float charge" at 13.6V. Which simply isn't enough, I use a conductance meter to measure the battery state and the only way I can get the battery on my S type fully charged is to use a mains charger every few weeks. I also wondered why it sets at 13.6V if the Smart charge system is involved, maybe it's a limitation of the alternator because I would expect the sensing system to read what the battery needs, not just give a fall back level of charge, something else to look at. If you have a 4.2 one, don't worry, it has a proper charging circuit unemcumbered by electronics... So I was particularly gratified to see Eric both remove the smart charge sense lead to let the alternator "run in auto" and take measurements... And also even more gratified when I spotted last time that Eric mentioned the AIT having an influence... Took me three viewings to spot that little nugget... Well it rarely gets that cold in the UK, -13C is considered exceptional (without the wind chill) and for a long time I have thought the Jaguar engineers missed something quite important when they converted the US smart charge system for UK use. So thanks again for the back log of interesting stuff to watch... I have to look at how I can influence the system on my car to give a few more volts now.

That's how i test them. Eric. Unplug it and if it doesn't charge the Alternator is toast. It takes very little charge to turn the battery warning light off.

I drive a 98 Mercury Tracer (so basically a ford). I don't think it has a smart charge system, but the alternator did die on it a few months ago. The light didn't come on until the battery had died or wasn't taking a charge, not 100% sure what caused the light, but when I took it to O'Reilly's to get the battery checked, their scanner found that the battery wouldn't charge, AND that the alternator wasn't charging. That was money I didn't want to spend, but my dad and I did the install ourselves, and (a few fuses later... unhook the battery first ya dummy) we managed to get it in and it seems to be working.

Sounds like the smart regulator is separate from the Generator Portion of the alternator. Default is 13.8 with "Command" to increase voltage.

i know this is an old video..but what eric o was saying about the alternator codes. i can tell you from experience that i had a ford 500 with this style charging system, and this car had a run of bad alternators over a 3 year period. And at times it would come in with the battery light on and codes stored for the alternator not charging. You could pull the codes and shut the car off and start it back up and the codes would be gone even when the alternator was still not charging. To answer the question on the alternator codes i would say that it must have to be a 2 trip fault or something along those lines, because the chance of seeing the battery light on when the car was actually broken was super rare. At one time it had a bad alternator that failed in a way that when it got super hot (phx az in summer) it would fail to send the mon signal and intermittently set the charging light, at other times it would be charging and sending the mon signal and still have the charge light on. So its a mystery and goes back to what all the old timers say about computer controlled circuts...its voodoo. Second thing, The test when you unplug the alternator and rev the engine to see if it charges(similar to a full field test) is super helpful and i first found that on identifix when diaging that 500. Its a quick test and very helpful if you understand how to apply it properly.

The description of the communication between the PCM and the alternator is kind of vague. It would be nice to see what the pusles look like in a couple of days after the battery gets completely charged and with a warm engine. Looks like you have all of the right tools to be able to figure it out. Nice.

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

"smart"? What a load of bollix lol nice work Dr O!

In looking at the electrical drawing its strange that the alternator charging output to the battery goes through two Fusible links in parallel to the battery POS. You should only have one fusible link to protect the POS wire going to the alternator as close as practicable to the battery POS terminal. A fusible link is a wire type with a wire gauge much smaller than the wire it is protecting to provide a known point of failure in case of a short circuit. The fusible link wire is designed to open and the insulation to bubble when overloaded so you can identify the fault by looking at the fusible link portion of the circuit, usually around 6 inches. You can by fusible link insulated wire on spools in various wire gauges to make your own repairs. Also, if you look at the wiring diagram you see a CAN bus between the PCM and the instrument cluster. Why not just put the alternator on the same CAN bus? You already use two wires as GEN COM and GEN MON and the CAN bus is only two wires. The original intent to have the PCM control and monitor the alternator is that the PCM would have a strategy to estimate battery state of charge and control the alternator to provide proper charging in the different battery charge states; Bulk, Absorption, Float, ETC. What year this strategy went into effect I don't know, but you may be able to find out if you look at the variables you can monitor with the scan tool that would indicate such a strategy is in place. Like battery state of charge, SOC. UPDATE: My Ford EVTM manual wiring diagram review for light vehicles with V8s from 1996 to 2008 indicates the reason Ford uses two 12 AWG fusible links to protect a single B+ 6 AWG (BK/O) GXL copper wire is that Ford did not specify a FL with a smaller gauge than 12 AWG. There is no 10 AWG or 8 AWG FL used for cars and light trucks (up to the base F150). So, Ford and the supplier decided to use two 12 AWG FLs in parallel. The dumb (as opposed to FORD smart alternators like shown in the video) alternator applications have a 20 AWG FL protecting the Alternator sense (A) terminal circuit (16 AWG single wire circuit), and two 12 AWG FLs protecting the B+ circuit (6 AWG single wire circuit), to protect the wiring in case the alternator shorts out internally on either of these two circuits. However, the paralleling of the two 12 AWG FLs is very unconventional for an OEM in this time period, and the question that a lot of technicians ask is what if one of the FLs fails due to corrosion or chaffing, will the other FL be able to correctly operate the circuit. I believe the answer is no. I think the preferred repair if there is a failure in one of the 12 AWG FLs would be to use a single 10 AWG FL of the same length (around 7 inches for Ford) to protect the 6 AWG B+ wire. Use non-insulated step down (10 AWG to 6 AWG Burndy butt splice using a hydraulic crimper) butt splices with RED dual wall heat shrink to make the connections. Do not solder FL connections. Ford often puts the A terminal sense at the same splice after the 12 AWG FLs which I find a little strange, you would think the sense wire would be connected directly to the battery POS or directly to the POS of the main power distribution box under hood. The two common failure modes of the 12 AWG FLs in parallel is blown due to short circuit of the B+ circuit (which is not very common unless the rubber terminal boot has rotted away) or failure in one due to corrosion (usually a nick in the wire and not at the splice) in the other, which leads to strange behavior until the other 12 AWG FL fails. Corrosion seems to be the more likely failure mode. If there are any technicians or engineers that know more about the alternator circuit parallel 12 AWG FLs approach please let me know.

Very thorough diagnosis sir.