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!!
Interested in stuff seen in the videos or the tools and toys Eric O. likes and uses? Check out the S.M.A. "A-Store" and help support the channel! : http://astore.amazon.com/httpswwwy0837-20
If an SMA Video has helped you out please consider giving using "Patreon" to help support us. The videos take real time to create and pull us away from real work that pays our bills. CLICK HERE: https://www.patreon.com/user?u=5031451
--Eric O.
Simply send and E-mail to SMAstickers @outlook.com including: your shipping address and e-mail address in the text, I in turn will send you a paypal invoice for $5 each USA or $6 each international. Let me know how many you want and as soon as the paypal invoice is paid I will ship them out ASAP! Thanks for your support of our channel!!
--Eric & Vanessa O.
Feel like sending some swag to SMA because you love the videos but don't know where to send it?
Just ship it here:
South Main Auto Repair
47 S. Main St
PO Box 471
Avoca, NY 14809
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.

45 thoughts on “Ford smart charge system alternator not charging”
  1. Avataaar/Circle Created with python_avatars SVTShane361 says:

    Curious, how will the vehicle act to unplugging the smart charge at the negative terminal?

  2. Avataaar/Circle Created with python_avatars Dennis Kenney says:

    I was hoping this video would help me with a similar problem; 2003 f250 5.4 battery light coming on intermittently, now not light, dead battery. New battery, new alternator, one of the two wires to the alternator has 12 the other nothing. Alternator not charging. Checked fuse links, seem good. Tried Forscan but can't get it to work. Guess I have to save a bank roll and take it to Ford. Unfortunately this video and all the others I've watched did not solve the problem.

  3. Avataaar/Circle Created with python_avatars E Jeter says:

    I've got a 2010 acura It says check charging system

  4. Avataaar/Circle Created with python_avatars John Flanagan says:

    Thanks! So if it's definitely a bad alternator, replace it without the ford 3-wire smart plug?

  5. Avataaar/Circle Created with python_avatars NaberAuto says:

    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 YouTube videos are made by dummies that don't know what they are doing.

  6. Avataaar/Circle Created with python_avatars R5000 Si says:

    Hi Eric I have a question on a 2016 mustang GT 5.0 if you using a battery charger then start the car while still use the external charger can that damage the smart ford charging system in any way. Thanks

  7. Avataaar/Circle Created with python_avatars Antonio Claudio Michael says:

    The high charge state makes sense when the battery is under 14 volts and it was at 11 volts and now its communicating constantly a d wow just stopped communicating again interesting Eric O @SouthMainAutoRepairLLC

  8. Avataaar/Circle Created with python_avatars Antonio Claudio Michael says:

    Interesting how it Doesn't Throw any codes Even with the Communication lines Unplugged 🤔 Eric O @SouthMainAutoRepairLLC

  9. Avataaar/Circle Created with python_avatars Antonio Claudio Michael says:

    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

  10. Avataaar/Circle Created with python_avatars Antonio Claudio Michael says:

    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

  11. Avataaar/Circle Created with python_avatars Steve Nonono says:

    It won't blow up will it 😎👍

  12. Avataaar/Circle Created with python_avatars Steve Nonono says:

    So what ur saying is since I have 2 batteries I can just disconnect the 3 prong plug and itl charge my batteries

  13. Avataaar/Circle Created with python_avatars ST says:

    Would not want that guy working on my house with the way he keeps his truck up.

  14. Avataaar/Circle Created with python_avatars Knickerless Witchcraft says:

    No wonder cars are so unreliable today.

  15. Avataaar/Circle Created with python_avatars topcityjose says:

    200 deep on a new alternator now watching this "Smart" charging to try to find what is wrong

  16. Avataaar/Circle Created with python_avatars Captains of the Azul Carrib says:

    Very interesting, thanks! 👍🏻

  17. Avataaar/Circle Created with python_avatars Jeff Dow says:

    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 😊🇦🇺

  18. Avataaar/Circle Created with python_avatars cype man says:

    Man, that was thorough.

  19. Avataaar/Circle Created with python_avatars Micheal Beach says:

    As for me with my expertise it pisses me off that the pcm would have a lot to due with charging. I followed most the testing. But even he was slightly confused confused with the readouts and why he wasnt getting the red light . Basically my testing skills arent that good so im going to replace my alternator. And if thats not it if its my pcm im gona be hot. Because at that point . I think my pcm is sticking its nose in too many places. Well until my battery starts overcharging anyways .but my usuaull problem is. My alt not charging. But i apppreciated the video. Thanks

  20. Avataaar/Circle Created with python_avatars tappedurmom says:

    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

  21. Avataaar/Circle Created with python_avatars RMCUSTOM says:

    Wow, man, who are you trying to impress brotha !???? There is absolutely NO NEED to go to that extensive troubleshooting length when a simple volt-meter & some solid experience could have & would have arrived at a much more useful conclusion & a MUCH less timely & costly repair !

    Then, on your OWN dime, take your theories & run w/them until your drooling in your sleep bud, because you have self-admitted that you can’t sleep at night due to the obsessive over thinking of an actual simple repaired electrical issue ! So, after ALL THAT BRAIN CRAMPING ! And after ALL THAT TIME (Labor) that the customer is being charged for, and paying YOU for….you only ended up w/the conclusion that the alternator was toast !??? Lol ! And you didn’t even diagnose/conclude what part of the alternator was causing this charging issue !???? Diodes, Rectifier, Stator, Brushes, Voltage-regulator, Etc !??? Or did you just install a new/rebuilt alternator in your customers truck & send him on his way w/a big FAT bill !?! No need to answer that. Just thought I’d spew off. Lol !

  22. Avataaar/Circle Created with python_avatars Skymning Forelsket says:

    So in the end the alternator was bad? But we never got to the bottom as to why the vehicle didn't set a BATTERY WARNING light on the dash, nor did we find out what was wrong with the alternator?

  23. Avataaar/Circle Created with python_avatars Toby Sirus says:

    If in case of over charging alternator condition will this "smart" system shut down voltage totally ?

  24. Avataaar/Circle Created with python_avatars tony castro says:

    blame this sht on the goverment who bends over because the so called global warming fanatics pass laws to force manufactures to come up with stupid sht like this,,,kind of like tpms,or flamible ac freon 1234y,,or the engine on/ off while in idle,,,etc etc,,lol,,,but hey fk it,,,keeps us busy fixing this sht,,,,,,,,,,,,,lol,,,tnx for video,,,,,,,,,,,,

  25. Avataaar/Circle Created with python_avatars Dennis Hoenich says:

    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.

  26. Avataaar/Circle Created with python_avatars 80MileKyle says:

    Real smart isn’t it

  27. Avataaar/Circle Created with python_avatars Thomas63r2 says:

    I don’t know if my 2006 Lincoln Town Car has the same smart charging system. Recently I was driving when first I noticed the mpgs seemed much lower on the dashboard display. Then a few miles later my dashboard digital gauges went out, but the analog gauges were still functioning. Before the dash digital gauges went blank the “battery” warning light never came on. A couple miles later the power steering became heavy. After pulling into my driveway I shut it off, and just got a click click when trying for a restart. It would start with a jump. The next day it restarted without a boost the first time, then needed a boost the second time. When I started going over everything I found a slightly low battery at ~ 11.8 volts. The alternator output was ~ 10.9 volts. Again, no warning light on the dashboard. I did not check for any computer command fir charging. I installed a new alternator and the alternator output increased to 13.6 volts (I expected ~ 14 volts), but now the battery was being charged.

  28. Avataaar/Circle Created with python_avatars larry anderson says:


  29. Avataaar/Circle Created with python_avatars Flavio G. says:

    Ford engineers must be f….k fired! I had 2 Ford's and they where a neverending mechanical and electrical problem! Why do you need to complicate a god damn battery charging system so much??? You are f….g charging a battery you piece of crap shitty engineers!

  30. Avataaar/Circle Created with python_avatars Robert F. Donahue says:

    I have a 2006 explorer that works about every 3rd time i start the engine, my battery light does come on when its sitting at 11.6 or less when its not charging, its a big battery so I am not worried much, I have never seen 14.6 LOL maybe 13.6, I have a digital on the dash aftermarket cause I am a Ham with radios and I want to know, 3 years never had an issue then all of a sudden I have an issue, I am also just going to change the Alt because I am pretty sure its the Int. Reg

  31. Avataaar/Circle Created with python_avatars Lonn Craw says:

    Clear throat and says under his breath guarantee his work 😆🤣😂

  32. Avataaar/Circle Created with python_avatars Dmk Pit says:

    still have BMS on my 2019 same issue come out dead no battery light but alternator wont charge battery, hit with jump box drive to my shop shut off still dont start, reset BMS turn key no jump box truck starts, i believe lightning storm last night screwed up BMS system, my dash cam was activated multiple times recorded nothing so must been storm

  33. Avataaar/Circle Created with python_avatars Mini-Band by Cunningham says:

    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…

  34. Avataaar/Circle Created with python_avatars E M says:

    ""Maintenance people, maintenance!", so true, and so often ignored until the vehicle fails on the operator. Sad that people don't get that it costs more in the long run to ignore maintaining their vehicle.

  35. Avataaar/Circle Created with python_avatars Doug Hunt Jr says:

    Smart charge equals Internet Access! just saying

  36. Avataaar/Circle Created with python_avatars RJ Cormac says:

    Great video

  37. Avataaar/Circle Created with python_avatars Ron Wade says:


  38. Avataaar/Circle Created with python_avatars trail457 says:

    You would think the power to the light should switch off and on to operate the alt. light.Stay on when charging so power is on both sides of the light.

  39. Avataaar/Circle Created with python_avatars Alex Gonz says:

    Impressive information tank u for sharing knowledge…👍👍👍👍👍🍺🍺🍺🍺🍺🍺🍺🍺🍺

  40. Avataaar/Circle Created with python_avatars Dependable Auto Truck says:

    why make it hard to diag when it used to be so simple either bad alt or reg miss the good old days computers help in many ways but make it hard in so many other ways

  41. Avataaar/Circle Created with python_avatars Marcus says:

    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..

  42. Avataaar/Circle Created with python_avatars Mr D says:

    37.30, do you think the light does not come on because it is waiting for some sort of a duty cycle?

  43. Avataaar/Circle Created with python_avatars Azhar_ Tech says:

    Such a confusing problem though you did it 👏👏

  44. Avataaar/Circle Created with python_avatars Cody Wichman says:

    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.

  45. Avataaar/Circle Created with python_avatars Ken Green says:

    do work Acura 2016 RDX

Leave a Reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.