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I know this video is 2 years old.. but i hope the owner of this car sued the original mechanic/shop for misdiagnosing his vehicle and all the labor costs! Great work my friend. Love Snap On Tools !
i have trouble thinking about my friends Hyundai elantra sir.the battery goes off when the engine runs and there's magnet in pulley and yet i have a 10v reading and the battery cannot fully charge.why is that?
I actually learned something! Thank you. I liked the "let's learn together approach" for this particular problem. You used your experience to lead you--and us--in the right direction and it paid off. Well done, sir!
I had a Ford that took me 4 alternators to finally get one that would charge. 2 Aftermarkets 1 Motorcraft (still didn't work) 1 one last aftermarket. I doubted my diagnosis a few times but once we got one with the correct regulator inside it worked like it was new.
I am a dealer tech (for a European brand). In about 2013 our manufacturer changed the out put of the alternator to keep the battery at about 12v and not much higher. This extends the life of the battery. They said the battery can last an additional 30% or something like that. Keeping the battery at 12v instead of 13 to 14 volts keeps it cooler and extends the life of the plates. Good video, I did not know hyundai did this as well.
I know it's been 2 years and I don't know if you'll see this question, but this is happening to me right now. If you don't mind my asking, what manufacturer?
I had these same symptoms on my F150. Threw me for a loop and and at first I swapped the alternator as well which didn't fix it. The actual cause for me was a bad ground from the engine to battery. This was tripping the computer up and when you had lights and heater on it couldn't source enough amps through the bad ground to keep up. So I just added an extra ground cable right to the engine mount of the alternator and ran it to the negative on the battery and not only did it fix the voltage problem but now my starter is much faster as well. I'm in the rust belt of Illinois so I am sure the original engine to frame/battery ground is corroded or gone. This situation is easy to test if you just use a set of jumper cables and only use the negative leads and connect one to batter and the other to a solid connection on the engine.
@@bruhbruhh5103 Run from negative to the mounting bolt on the alternator. Any bolt on the motor that isnt going to cause a leak or problem will work. Motors are isolated by rubber mounts so they need a ground strap to keep them connected electrically to the frame and battery. When the oem ground strap rusts and fails you get random electrical problems. Usually those oem straps are in the back or bottom of the engine and can be a pain to get to. You are just accomplishing the same thing but up top where its easier to get at and maintain. You are not disturbing the red positive wire on the alternator. You are just looking to add ground path to the engine.
An excellent video. Like the man says Do your homework. Some people's comments of changing out three batteries and alternators. That shows no knowledge of the issues. I have learned something from this video. Thank you.
I had a similar issue a couple of years ago, one of the guys at the shop changed out 2 alternators in 2 days and the car got towed back the day after fitting each unit after breaking down with a flat battery. I had to check it out after it got towed back the second time and it was charging fine, both loaded and unloaded, I couldn't find anything wrong with it. Then I got to thinking, it was the middle of winter at the time so there would be a big continuous load on the alternator, so I let the engine run for 15 mins with the heater fan and lights on, came back and battery voltage was 12.something volts. Turns out part of the cable from the alternator to battery positive was corroded so the voltage drop got worse the longer the alternator was under load. Since then, I always load the alternator for at least 10 mins after the initial check.
@@sh2697 The battery was being drained because the alternator couldnt charge it. The alternator was outputting 14.5 volts but the battery was getting less than 11volts (I'm assuming less than 11v because the lowest I measured was 11.3ish) while the customer was driving through the night, they noticed the headlights were getting dim (again), they stopped and the car and it wouldn't start again because the battery was flat. There was so much resistance in the corroded cable, it partially melted the junction box
I’m pretty sure something like that is causing my alternator to not charge the battery. I’m dreading trying to find the problem. Alternator bench tested fine. 3 new batteries. Alternator isn’t charging the battery.
Smart systems are stupid back in the day if yiu needed a alternator or battery you go buy it and problem solved. Never buying new cars ever im keeping only my good 90s cars
Good job man. You just showed again scan tools are a great help . But we do have to know how the systems work in order to come up with the most accurate diag. That means we need access to information . Newer cars are loaded with high tech. We have to educate ourselves more than ever. God bless.
Had a customer back in the day, replaced alternator, regulator and battery. Battery would still be dead after sitting overnight. When he dropped the car off he left the keys in the glove box. First thing I noticed was the switch for the glove box light was dangling behind the glove box. Turns out the trunk light was always on too.
My 06 Nissan Frontier 4.0L V6 will start out at 14.0 volts then ramp down to 12.9. When lights, A/C, wipers, etc are added, it still maintains 12.9 to 13.0 but the current output increases until the loads are removed. It's normal for the system to do this. Good diagnosis Oz.
I don't know in the US but in Europe that is a feature that most new cars have. I've tested that in a european 2013 ford focus (so 8 years ago). Ford calls that systen "micro-hybrid" because it recovers energy when you aren't accelerating. For the whole system to work, it has a controller that measures current going in and out of the battery and knows the charge. If the battery doesn't need to be charge, the voltage would be around 12.5V or something like that, even lower when the start&stop system stops the engine because all the electronics are working but the alternator is stopped. In this way the car consumes less fuel. If you're driving around and lift the accelerator pedal, the system engages the alternator and it'll go to 14.4V or so because that is "free energy". In the case that the battery is too low, the system will charge the battery and you'll see 14.4V even at idle and the start&stop system won't work until the battery is charged to a certain level. You have to be careful when changing the battery though. You have to reset this controller (at least in the ford focus) in order for the system to recognise that it has a new battery. We had to change the battery once and I told the techinician to do it (they had a tool from EXIDE to do this) but he insisted it wasn't necessary. The result was that 2 months later the battery was dead. They replaced the battery in warranty and reseted the system and everything worked fine then.
Great advice = do your research BEFORE changing parts ! As long as the battery was checked and no parasitic drain it should be fine . Today's JOKE : the customer asked the other shop if they checked for parasitic drain . They told him to " Call a PLUMBER " !
Yes my 2012 Honda Civic does exactly the same thing as soon as you start the car the alternator is charging the battery to 13.5 -14.7 and after a minute or 2 it drops the voltage back to about 12.3-12.6 I almost changed the alternator after replacing my dead battery which was the original problem and did a test by simply turning on the air conditioner and seeing the voltage jump to 14.5-14.7 and later letting the alternator charge the battery it went down back to 12.3 -12.6 volts and as long your battery light on your dash does not illuminate your good to go but thank you for proving that with you scanner as I don’t have one 😊
Yea, I got my butt wiped on one when I was so focused it was like a regular alternator. And I didn’t help I didn’t have service information in my finger tips
@@OzMechanics yeah, painful to deal with the first time if you aren't aware of them 😂😂, I had issues with one a long time ago and just assumed it was a faulty regulator 😂 swap it out....still faulty.....then I started hunting...... Always pays to research before throwing parts at it.....especially 3 alternators😂😂😂
Great video, I thought my alternator was not charging would stay around 12 had to restart the car 3 times before the voltage would go around 14! guess it saw batterie had gone down from me starting the car 3 times in a row before it considered turning up the demand on the alternator. Great and informative video!
I noticed you were from Texas. I live in League City. I just replaced my alternator on my 2013 Hyundai Elantra GT with a remanufactured one from Amazon. It worked perfectly for about an hour but failed catastrophically within about an hour. At this point I don't know if the new alternator failed or something else is causing it to fail. I'm going to have the new alternator checked today and go from there. If I can't figure it out I might come see you.
Morning Kevin I just recently recorded a video where the customer bought some amazon spark plugs and they ended being cheap aftermarket knock off that had the OEM name on them. Caused a lot of problems
Yup, they aren't going to charge more if there is no need. Back in my day we had older testers that had carbon pile testers in them. One could turn up the resistance and if the alternator started to charge more then one knew that it was ok. What was fun is to increase the resistance to see how good they were to the point they went below 12v. If that eng was still running then you knew the alt was really good. If it went below 12v rather early then you knew you pretty much had had brushes. Good job in diagnosing that no problem issue !
This explained a lot for me - thanks for the video sharing the knowledge. I have a Volvo C30 1.6D Drive (Full of eco baloney). First alternator failed spectacularly. No question on that one. Second failed after 5 months - was a cheap unbranded replacement. Third one which is the current one displays the same behaviour as the vehicle in this video. Smart alternator. As low as 12.7 a idle, atnd tops at 14V under load. Indy garage that fitted this latest one wasn't convinced it was working correctly until I showed them this video. They learned something too...
Thank you! Accord 2006, same issue, ordered a new alt thinking mine was bad. While driving I noticed my phone charger displays car voltage, went from 14.1v to 12.5v then back. I will try the headlight trick. Thanks!!!
I wouldn’t this applies to newer vehicles. But I will be filming a video tomorrow on an older vehicle that has had 3 alternators replaced and it’s an older one
I just ran thru 2 alternators thinking they were broken on my 2012 civic because the battery died after running the AC and music for 5m idling. Because the headlights weren't on, it didn't trip up to 14V and that was apparently enough to drain it.
Most of the computer controlled alternators these days have load dependant charging, emmisions and efficiency and all that are a big thing, no point in driving a load that isn't needed
@@sh2697 The alternator on the vehicle was working correctly, under conditions when there was minimal electrical consumption, the control system was turning the alternator off, some people don't know of this function on some modern vehicles and it can be mistaken as a faulty alternator.
@@2secondslater Spot on! It's been available on cars for a few yeas. My first EFI car (manufactured in 2006) had a computer controlled alternator. If you want to learn more about your car, download and read the manufacture's repair manual (one the one used by the dealership mechancis to repair your car). It contains heaps of useful info on how your car works!
Thank you for the video, I'm in the middle of this on an '04 Corolla. Can you remember if the customer's battery light was one? Mine is. I will check codes and repeat the drop tests. I replaced battery and alternator already. Thanks!
Hi Thanks for the Great channel and Great videos. I would sugest you notify the name of the workshop in order to get More customers in touch with a honest mechanic like you. Further More it would be Great IF there was some More info on the overall cost of the repair including How manny hours of work is suited for each Job respectivly.. Anyways i did enjoy the videos and picked up a trick or two from you so thank you 👍 🇦🇱 🇺🇸.
I am having an issue with load at the moment. Alternator failed and then replacement failed. Supplier was good and replaced it & tested it before sending and the auto elec also tested it. No issues. I am now finding lights dip and fans slow when I lift off power. The power dip is fluctuating at lower engine speeds. When driving at night if I lift off power the lights dip. Regulator on alternator is fine. It is a 1999 BH9 Subaru Outback 2.5. I was wondering what else could cause the issue. I can feel an issue developing with power steering pump (it has become jerky) which is on same belt. Could it cause an issue.
I have question I have a 2005 corvette with a built engine my alternator when the voltage goes down to 12.2 the velts make a noise when it starts charging again no noise so I sent my alternator to California have them rebuilt it I put it back on the car and still does the same thing but still a round 12 please give me an idea 💡
Sir I didn't understand actually what's happening to this car I need to know what is the solution you found in this car please give reply I am waiting for your reply..... N I really want to say thank you for sharing your knowledge n I am learning a lot by watching your videos you are doing a great job thanks once again
There was actually no problem. The customer was thinking that because it read 12.5 volts it wasn’t charging but with this system it’s a smart charge. So it charges at 12.5 at no load but jumps when we add load to the engine
I also see the alternator has an over running clutch on the pulley. These allow the alternator to spin free at certain times and can also show low voltage under no load. I should add that by accelerating the engine, you should see the voltage increase and decel will let the alternator free wheel and lower voltage.
Yes Nice Diagnosis and research , i always like to see my Alternator Compensating Voltage whilst under load ,,,enjoyed The video well explained ...........
That obd looks expensive and very informative. So it charging at a higher rate is normal when under load I had replaced 2 alternators and changed brand on the third one to get constant 12v even under load my god your awesome
Great video in diagnosis of the problem but you never explained what you did to actually fix the problem. If you could give a explanation as to what the really issue was. I 've been having this same issue with a different vehicle. Alternator and battery has been replaced twice. Some more insight would be much appreciated. Thank you for time in effort you put in.
I did explain it in the whole video. I’m not sure why the alternator was replaced the first time but when the customer brought it to me they were concerned that the alternator was only producing 12.6 volts and I verified that on this car that is normal. That this vehicle is equipped with a smart charge system that produces 12.6 volts at light idle with no load but as soon as loads are introduced the voltage goes up. There’s even a chart from service information that explains that close to the end of the video. Feel free to rewatch it now to see what I am talking about
I just had my alternator swapped out in my 22 Kia, The voltage while idling was 12.7 with zero load. Battery voltage drops during the night. What's the issue here? Car starts with no issues aswell.
It’s 12.7 on a smart charge system is normal. Like explained on this video. Try the same thing I did on this video and check battery voltage with headlight and ac on
No issues it's called a smart alternator as it's got a little black box on the negative terminal side witch tells the alternator to charge the battery at a higher or lower voltage
If Exciter wire is not getting 12V then it’s not powering up the voltage regulator therefore it won’t keep the battery at a good voltage level . It’ll either over charge or not give enough charge to the battery
Well In this vehicle due to all the economy features. They have a smart charge system that stays at 12v at idle with no load and jumps up when ever load is applied
My Ford has a 'generator voltage desired' pid. Is that equivalent to the duty cycle desired (obviously in a different format VDC vs DC%) in that hyundai or is that not a fair 1:1 comparison in one way or another?
But initially why did the customer change alternators is he never had a battery problem? Anyway, this is my 2nd new alternator, and my reading is the same 12.6 I will check like what you did too, I have 2011 Town and Country.
2011 Town and country doesn’t have a smart charge system like the vehicle I’m working on, on this video. What part of the us are you in ? I could direct you to a tech that I know that could perform a proper diagnostic
I noticed that exact same problem on my Subaru, when I was trying to jumper lead charge my solar Batteries, then I noticed the Charge increase when I switched on my Park Lights.
Part of the "squeeze every mile/km out of that gallon/liter of gas" computer programming. Depending on the type of battery, it may also give longer battery life. Looks like a good method of controlling battery charging but this needs to be in the owner's manual: "Battery voltage is not always 13.8 volts. It varies with the electrical load and the battery's state of charge. Voltages of 12.5 to 14.4 are normal when the engine is running." Me? I've built a couple of small solar systems (shed lighting, "Wait until daylight" backup power) so I'm very aware of the trade-offs in battery charge level versus battery life. My previous set of AGM batteries (typical life of 5-7 years) were replaced a few months before their 9th birthday.
By the way, the car is equipped with stop/start system? If yes, then that is the normal behaviour of the alternator. My Renault from 2014 also acts like this, it goes to about 14 volts only when the headlights are on so when an important load is present.
Great work man. It’s funny that we’ve had smart alternators for quite some time but people still don’t realize it. Superb explanation of the system and showing how it works. One question I have. Did the versus not have the PIDs for duty cycle?
In the issue customer thought that because the battery was charging at 12 volts at idle that the alternator was bad. The thing is I found that this car is has smart charge and I performed test that showed 12v at idle is normal. Did you see that part of the video ?
I believe the first problem was an alternator. But after the new alternators were installed he would check the voltage and notice it would be 12 volts and he would take it back to get it replaced
@@OzMechanics well I guess we all have to learn the hard way. I got caught on my honda with this issue as well, change the Alternator and battery bc they were both bad and had the same readings and started testing based of of the readings, bench tested the Alternator and said hmmm...so I went and used my buddy subscription to pro demand and learned about smart charging. The vehicles are becoming to smart..IMO making them stupid lol. Thanks for what you do!
Had same issue on my truck come to find out the amps on the alternator that parts store gave me didn't match the amps for my truck as per Haynes manual putting more higher amp alternator won't make light of check charging system turn off putting the required correct amp alternator worked light turned off.
@@OzMechanicsYeah, I did. Great video and great job doing thorough tests and research on a customer complaint. It's just that I think a faulty ELD will make the ECU command a lower duty cycle (or higher, sometimes). There have been such cases on some Honda's. So, maybe a research on the ELD signals could be for another video? Just a suggestion. Cheers.
I have a 2018 Durango and I had electrical issues. First the main battery went dead no start no crank. Apparently the auto stop/start battery was already dead. The dealership couldn’t find the problem. Second visit they found the stop/start battery was officially diagnosed dead. 230$ later the system worked. Then the main battery went dead again. Diagnosed as a dead cell and was replaced 460$. Now the alternator under acceleration load will drop to 12.8. No load coasting 14.5 same at idle. Chrysler said this is normal logic from the ECM. To me it seems counter intuitive
Damn bro, you saved me from changing my alternator from a 2nd time! I just got my alternator rebuilt and was about to take it back because I wasn’t getting a higher voltage than 12.5 until I did the battery load test and the voltage started going up like the video. I got a Honda accord 2016. What Honda were you referring too?
Awesome 😎 glad this video helped you out. I believe it was a Hyundai Electra if I’m not mistaken. Yea, these smart charge systems can take you on a loop. Thanks for watching
My check charging system is on in my 2012 civic si. I replaced the alternator and it fixed it for 3 months and then came back on and now can't drive it . Keeps not charging my battery
OZ, AWESOME it is great and the right way first to do ur basic checks as u did and read the info to verify the way system work thanks for sharing brother.cheeeeers
I have a 2013 avenger it won’t stay on after I jump start it.. I called the dealer & they told me the car should still run after jump starting it but the battery is so dead advanced auto reading came back with no Cranking amps. I’ve changed the alternator twice & still have this problem
i think what you did would help my problem.....but I dont understand what you did! My Jeep is acting like the alternator is bad but I have no codes!! Did you actually do anything?? I checked the throttle body and it does need cleaning bad! I didnt have enough cleaner to clean it good. Maybe thats the only problem. But if youre saying the alternator adapts to the situation,that helps.
Yes like on the video explained. When the vehicle is in idle with no load the alternator is only pulling around 12 volts but as soon as we put load to the vehicle exp turn ac on or headlights the computer commands the alternator to push 14 volts. This was a test showing that the vehicle was working as intended. As well we pulled out service information for that vehicle which also showed the operations. So I’m confused as when you asked if I actually did anything
Interesting troubleshooting and analysis of the data. What started all the replacement alternators in the first place ? Customer measuring the 12.3 V and then assuming that’s a problem?
The first time they replaced the battery, I’m sure it was probably because of a bad alternator. But the customer ended up telling me later on that he checked it out because his battery was drained, but told me that he believed he left the lights on. I verified That with a parasitic draw test and also the alternator test that was done on the video.
@@OzMechanics Thanks for your follow up reply. I have a 2015 Accord and connecting my DMM a few times noticed similar voltage readings. Didn’t realize PCM controls alternator voltage with newer cars.
Since our cars have computers nowadays and those computers can be accessed through OnStar can dealerships send false codes to our cars and trucks for us to bring them in for maintenance
Great video Oz, this is the 1st alternator video I've ever seen on RUclips indicating ~ 12.4 Vdc at Idle. I believe most of the Alternator videos I've seen would have called this a Bad Alternator, do you know if a 2006 Toyota Tundra would operate like this Hyundai, i'm always monitoring the Alternator voltage and it seems Low ~ 12.6 to 12.4 at idle but when cruising and off idle voltage jumps up to 13.6 to 14.1. Thanks again for your video.
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I know this video is 2 years old.. but i hope the owner of this car sued the original mechanic/shop for misdiagnosing his vehicle and all the labor costs! Great work my friend. Love Snap On Tools !
Scan tool link was not like the one you were using. What snapon do you have
i have trouble thinking about my friends Hyundai elantra sir.the battery goes off when the engine runs and there's magnet in pulley and yet i have a 10v reading and the battery cannot fully charge.why is that?
😂 The other shops replaced 3 alternators and couldn’t figure that out. Good job! 👍
Looks like they replaced it with an old dusty alternator, three times.
I actually learned something! Thank you. I liked the "let's learn together approach" for this particular problem. You used your experience to lead you--and us--in the right direction and it paid off. Well done, sir!
Thanks for watching
That was pretty cool to see the graph confirm the operation.
I had a Ford that took me 4 alternators to finally get one that would charge. 2 Aftermarkets 1 Motorcraft (still didn't work) 1 one last aftermarket. I doubted my diagnosis a few times but once we got one with the correct regulator inside it worked like it was new.
Must have been an 06 mustang gt
I am a dealer tech (for a European brand). In about 2013 our manufacturer changed the out put of the alternator to keep the battery at about 12v and not much higher. This extends the life of the battery. They said the battery can last an additional 30% or something like that. Keeping the battery at 12v instead of 13 to 14 volts keeps it cooler and extends the life of the plates. Good video, I did not know hyundai did this as well.
Did they go to AGM batterys?
@@ScottDLR some use AGM, but some still used lead acid. Newer use lithium ion. As well we use a new 48 volt lithium ion
I know it's been 2 years and I don't know if you'll see this question, but this is happening to me right now.
If you don't mind my asking, what manufacturer?
@@soundfarm8814 Mercedes Benz
what about is the changing ligth is on in the dashboard?
Thank you for your patience and diligence. Yr tenacity shows great job 👍
Dang you went above and beyond explaining this one! Thanks! 👍
I just felt I had to explain piece by piece to really get to the point of this issue
I had these same symptoms on my F150. Threw me for a loop and and at first I swapped the alternator as well which didn't fix it. The actual cause for me was a bad ground from the engine to battery. This was tripping the computer up and when you had lights and heater on it couldn't source enough amps through the bad ground to keep up. So I just added an extra ground cable right to the engine mount of the alternator and ran it to the negative on the battery and not only did it fix the voltage problem but now my starter is much faster as well. I'm in the rust belt of Illinois so I am sure the original engine to frame/battery ground is corroded or gone. This situation is easy to test if you just use a set of jumper cables and only use the negative leads and connect one to batter and the other to a solid connection on the engine.
Clever! I like it!
Thanks for information
Ok ok let's try it.
So I can run a cord from the negative to the alternator on top of the over wire?
@@bruhbruhh5103 Run from negative to the mounting bolt on the alternator. Any bolt on the motor that isnt going to cause a leak or problem will work. Motors are isolated by rubber mounts so they need a ground strap to keep them connected electrically to the frame and battery. When the oem ground strap rusts and fails you get random electrical problems. Usually those oem straps are in the back or bottom of the engine and can be a pain to get to. You are just accomplishing the same thing but up top where its easier to get at and maintain. You are not disturbing the red positive wire on the alternator. You are just looking to add ground path to the engine.
An excellent video. Like the man says Do your homework. Some people's comments of changing out three batteries and alternators. That shows no knowledge of the issues. I have learned something from this video. Thank you.
I had a similar issue a couple of years ago, one of the guys at the shop changed out 2 alternators in 2 days and the car got towed back the day after fitting each unit after breaking down with a flat battery.
I had to check it out after it got towed back the second time and it was charging fine, both loaded and unloaded, I couldn't find anything wrong with it. Then I got to thinking, it was the middle of winter at the time so there would be a big continuous load on the alternator, so I let the engine run for 15 mins with the heater fan and lights on, came back and battery voltage was 12.something volts. Turns out part of the cable from the alternator to battery positive was corroded so the voltage drop got worse the longer the alternator was under load.
Since then, I always load the alternator for at least 10 mins after the initial check.
so if it broke down, may i ask what the problem was
@@sh2697 The battery was being drained because the alternator couldnt charge it. The alternator was outputting 14.5 volts but the battery was getting less than 11volts (I'm assuming less than 11v because the lowest I measured was 11.3ish) while the customer was driving through the night, they noticed the headlights were getting dim (again), they stopped and the car and it wouldn't start again because the battery was flat.
There was so much resistance in the corroded cable, it partially melted the junction box
Great advice, sir. Thanks!
I’m pretty sure something like that is causing my alternator to not charge the battery. I’m dreading trying to find the problem. Alternator bench tested fine. 3 new batteries. Alternator isn’t charging the battery.
Smart systems are stupid back in the day if yiu needed a alternator or battery you go buy it and problem solved. Never buying new cars ever im keeping only my good 90s cars
Good job man. You just showed again scan tools are a great help . But we do have to know how the systems work in order to come up with the most accurate diag. That means we need access to information . Newer cars are loaded with high tech. We have to educate ourselves more than ever. God bless.
That is 10000% true.
Had a customer back in the day, replaced alternator, regulator and battery. Battery would still be dead after sitting overnight. When he dropped the car off he left the keys in the glove box. First thing I noticed was the switch for the glove box light was dangling behind the glove box. Turns out the trunk light was always on too.
Parasitic draw....
Might it have been wise to turn lights, heater fan, rear defroster, ecg and then checked to see that alternator puts out amps it is rated for?
My 06 Nissan Frontier 4.0L V6 will start out at 14.0 volts then ramp down to 12.9. When lights, A/C, wipers, etc are added, it still maintains 12.9 to 13.0 but the current output increases until the loads are removed. It's normal for the system to do this.
Good diagnosis Oz.
Thanks! Been servicing cars for many years and learned new information here.
I don't know in the US but in Europe that is a feature that most new cars have. I've tested that in a european 2013 ford focus (so 8 years ago). Ford calls that systen "micro-hybrid" because it recovers energy when you aren't accelerating. For the whole system to work, it has a controller that measures current going in and out of the battery and knows the charge. If the battery doesn't need to be charge, the voltage would be around 12.5V or something like that, even lower when the start&stop system stops the engine because all the electronics are working but the alternator is stopped. In this way the car consumes less fuel. If you're driving around and lift the accelerator pedal, the system engages the alternator and it'll go to 14.4V or so because that is "free energy". In the case that the battery is too low, the system will charge the battery and you'll see 14.4V even at idle and the start&stop system won't work until the battery is charged to a certain level.
You have to be careful when changing the battery though. You have to reset this controller (at least in the ford focus) in order for the system to recognise that it has a new battery. We had to change the battery once and I told the techinician to do it (they had a tool from EXIDE to do this) but he insisted it wasn't necessary. The result was that 2 months later the battery was dead. They replaced the battery in warranty and reseted the system and everything worked fine then.
Really interesting and great info, thanks!
You should check voltage drop while the alternator is
loaded-- carbon pile, accessories .etc.
Had the same thing on a Honda. Smart charging. That system out smarted me
Yep, that’s the first one that kicked my rear end
Honest mechanic👌
Wow did not expect that! Learned something new today.
Yep, in automotive, it’s always some new and fun to find out
Nice video. You see this on ford's a lot. The commutation wire going to the ecu brakes lite comes on and out put from altanator is 14 + voltage.
Very informative. I wish your shop was closer to my location. Thank you!
Nice breakdown I had same situation on nissan altima , alternator output adjust to the load great job
Great advice = do your research BEFORE changing parts ! As long as the battery was checked and no parasitic drain it should be fine . Today's JOKE : the customer asked the other shop if they checked for parasitic drain . They told him to " Call a PLUMBER " !
I could not really figure out what the actual problem was after running these tests please help me understand
Good work
Alternators will not charge 14v all the time while running to avoid damaging the battery in certain vehicles. Great work!
Yes my 2012 Honda Civic does exactly the same thing as soon as you start the car the alternator is charging the battery to 13.5 -14.7 and after a minute or 2 it drops the voltage back to about 12.3-12.6 I almost changed the alternator after replacing my dead battery which was the original problem and did a test by simply turning on the air conditioner and seeing the voltage jump to 14.5-14.7 and later letting the alternator charge the battery it went down back to 12.3 -12.6 volts and as long your battery light on your dash does not illuminate your good to go but thank you for proving that with you scanner as I don’t have one 😊
Great video, clear concise and presented extremely well..... many thanks! 👍
Field sensing alternators are suppppeerrr common on late model cars, good trick for beginners to check that first
Yea, I got my butt wiped on one when I was so focused it was like a regular alternator. And I didn’t help I didn’t have service information in my finger tips
@@OzMechanics yeah, painful to deal with the first time if you aren't aware of them 😂😂, I had issues with one a long time ago and just assumed it was a faulty regulator 😂 swap it out....still faulty.....then I started hunting...... Always pays to research before throwing parts at it.....especially 3 alternators😂😂😂
That's how the manufacturers up the gas mileage by adjusting the field current with the pcm.
Thank you this was extremely helpful
As a tech myself I never knew this
Nice job , Research pay's off .
Thank you Oz. Good job. Have a blessed and safe week to you and your family.
Great video, I thought my alternator was not charging would stay around 12 had to restart the car 3 times before the voltage would go around 14! guess it saw batterie had gone down from me starting the car 3 times in a row before it considered turning up the demand on the alternator. Great and informative video!
I don’t see how shops are still missing things like this. Smart charging systems have been around for years now.
I noticed you were from Texas. I live in League City. I just replaced my alternator on my 2013 Hyundai Elantra GT with a remanufactured one from Amazon. It worked perfectly for about an hour but failed catastrophically within about an hour. At this point I don't know if the new alternator failed or something else is causing it to fail. I'm going to have the new alternator checked today and go from there. If I can't figure it out I might come see you.
Morning Kevin I just recently recorded a video where the customer bought some amazon spark plugs and they ended being cheap aftermarket knock off that had the OEM name on them. Caused a lot of problems
Yup, they aren't going to charge more if there is no need. Back in my day we had older testers that had carbon pile testers in them. One could turn up the resistance and if the alternator started to charge more then one knew that it was ok. What was fun is to increase the resistance to see how good they were to the point they went below 12v. If that eng was still running then you knew the alt was really good. If it went below 12v rather early then you knew you pretty much had had brushes. Good job in diagnosing that no problem issue !
This explained a lot for me - thanks for the video sharing the knowledge.
I have a Volvo C30 1.6D Drive (Full of eco baloney).
First alternator failed spectacularly. No question on that one.
Second failed after 5 months - was a cheap unbranded replacement.
Third one which is the current one displays the same behaviour as the vehicle in this video. Smart alternator. As low as 12.7 a idle, atnd tops at 14V under load.
Indy garage that fitted this latest one wasn't convinced it was working correctly until I showed them this video. They learned something too...
Learned something new. Never seen that....
Thank you! Accord 2006, same issue, ordered a new alt thinking mine was bad. While driving I noticed my phone charger displays car voltage, went from 14.1v to 12.5v then back. I will try the headlight trick. Thanks!!!
I wonder if a 2004 Ford focus se 2.3l has the same problem
I wouldn’t this applies to newer vehicles. But I will be filming a video tomorrow on an older vehicle that has had 3 alternators replaced and it’s an older one
that was a useful insight.
Could you tell us about the current at the moment of cranking?
A data driven tech... wow! Good stuff, although that seems a bit dicey to me if you use vehicle for short, low load trips.
I just ran thru 2 alternators thinking they were broken on my 2012 civic because the battery died after running the AC and music for 5m idling. Because the headlights weren't on, it didn't trip up to 14V and that was apparently enough to drain it.
if the alternator is good,then what is causing the voltage to drop? how about the wiring?
Did you watch the whole video ?
Gotta love computer controlled alternators,,,,I also had my ass handed to me on a 2016/chev 1500 pick up !
Most of the computer controlled alternators these days have load dependant charging, emmisions and efficiency and all that are a big thing, no point in driving a load that isn't needed
so the car didnt charge. something was wrong. Can someone tell me what was replaced? I really like the snap on tool you have
@@sh2697 The alternator on the vehicle was working correctly, under conditions when there was minimal electrical consumption, the control system was turning the alternator off, some people don't know of this function on some modern vehicles and it can be mistaken as a faulty alternator.
What he said ^ I was curious to see your test method txt book checking , good vid
Its called elc.engine load detector
@@2secondslater Spot on! It's been available on cars for a few yeas. My first EFI car (manufactured in 2006) had a computer controlled alternator. If you want to learn more about your car, download and read the manufacture's repair manual (one the one used by the dealership mechancis to repair your car). It contains heaps of useful info on how your car works!
Thank you for the video, I'm in the middle of this on an '04 Corolla. Can you remember if the customer's battery light was one? Mine is. I will check codes and repeat the drop tests. I replaced battery and alternator already. Thanks!
The more challenging task: writing up the repair order in language the customer can comprehend
That was really hard. But I will show them this video so that can help out as well
Hi
Thanks for the Great channel and Great videos.
I would sugest you notify the name of the workshop in order to get More customers in touch with a honest mechanic like you.
Further More it would be Great IF there was some More info on the overall cost of the repair including How manny hours of work is suited for each Job respectivly..
Anyways i did enjoy the videos and picked up a trick or two from you so thank you 👍 🇦🇱 🇺🇸.
I’ll make sure to use these. Thanks for watching
I am having an issue with load at the moment. Alternator failed and then replacement failed. Supplier was good and replaced it & tested it before sending and the auto elec also tested it. No issues. I am now finding lights dip and fans slow when I lift off power. The power dip is fluctuating at lower engine speeds. When driving at night if I lift off power the lights dip. Regulator on alternator is fine. It is a 1999 BH9 Subaru Outback 2.5. I was wondering what else could cause the issue. I can feel an issue developing with power steering pump (it has become jerky) which is on same belt. Could it cause an issue.
I have question I have a 2005 corvette with a built engine my alternator when the voltage goes down to 12.2 the velts make a noise when it starts charging again no noise so I sent my alternator to California have them rebuilt it I put it back on the car and still does the same thing but still a round 12 please give me an idea 💡
The alternator brand is DC power engineering
Sir I didn't understand actually what's happening to this car I need to know what is the solution you found in this car please give reply I am waiting for your reply..... N I really want to say thank you for sharing your knowledge n I am learning a lot by watching your videos you are doing a great job thanks once again
There was actually no problem. The customer was thinking that because it read 12.5 volts it wasn’t charging but with this system it’s a smart charge. So it charges at 12.5 at no load but jumps when we add load to the engine
My 83 Toyota 22r does this exact thing with an external voltage regulator?
My Honda Accord Sport does this. So I knew immediately they got ripped off =). Subbing brother.
I also see the alternator has an over running clutch on the pulley. These allow the alternator to spin free at certain times and can also show low voltage under no load. I should add that by accelerating the engine, you should see the voltage increase and decel will let the alternator free wheel and lower voltage.
Yes Nice Diagnosis and research , i always like to see my Alternator Compensating Voltage whilst under load ,,,enjoyed The video well explained ...........
What is the rule of thumb for "Old School " non ECM/PCM cars? I believe that it should be ~13.6V at idle regardless of load.
do you think 2007 toyota rav4 2.4 work the same, i ready replace 3 alternator aftermarket end o got the same like your video..
That obd looks expensive and very informative. So it charging at a higher rate is normal when under load I had replaced 2 alternators and changed brand on the third one to get constant 12v even under load my god your awesome
Great video in diagnosis of the problem but you never explained what you did to actually fix the problem. If you could give a explanation as to what the really issue was. I 've been having this same issue with a different vehicle. Alternator and battery has been replaced twice. Some more insight would be much appreciated. Thank you for time in effort you put in.
I did explain it in the whole video. I’m not sure why the alternator was replaced the first time but when the customer brought it to me they were concerned that the alternator was only producing 12.6 volts and I verified that on this car that is normal. That this vehicle is equipped with a smart charge system that produces 12.6 volts at light idle with no load but as soon as loads are introduced the voltage goes up. There’s even a chart from service information that explains that close to the end of the video. Feel free to rewatch it now to see what I am talking about
@@OzMechanicsdidn’t you say he had replaced it3 times?
What about if the battery light flashing when the voltage drops to 12.9 in Hyundai Toscana 2020 engine 2.0
I had the same problem. I cleaned the rust on the alternator and changed the rusty bolt and everything was sorted
Nice Troubleshooting there, Some folks don't understand System Description, lack of comprehension, They just shot-gun parts
Something new I learned today. Thanks a lot man 👍👍
I have that in grand marquis 2001 ? How can i fix it ??😓
smart charge ,good video cheers
I just had my alternator swapped out in my 22 Kia, The voltage while idling was 12.7 with zero load. Battery voltage drops during the night. What's the issue here? Car starts with no issues aswell.
It’s 12.7 on a smart charge system is normal. Like explained on this video. Try the same thing I did on this video and check battery voltage with headlight and ac on
@@OzMechanics I shall, Appreciate the reply👍🏻
You have a new subscriber from Canada
Years years ago on a 2003 expedition that's happen to me. Ended up with fusebox internal soldering was bad resoldering an boom fix it
No issues it's called a smart alternator as it's got a little black box on the negative terminal side witch tells the alternator to charge the battery at a higher or lower voltage
If Exciter wire is not getting 12V then it’s not powering up the voltage regulator therefore it won’t keep the battery at a good voltage level . It’ll either over charge or not give enough charge to the battery
Well In this vehicle due to all the economy features. They have a smart charge system that stays at 12v at idle with no load and jumps up when ever load is applied
My Ford has a 'generator voltage desired' pid. Is that equivalent to the duty cycle desired (obviously in a different format VDC vs DC%) in that hyundai or is that not a fair 1:1 comparison in one way or another?
What was the customer complaint if the system is working properly? I would assume battery drain overnight.
But initially why did the customer change alternators is he never had a battery problem? Anyway, this is my 2nd new alternator, and my reading is the same 12.6 I will check like what you did too, I have 2011 Town and Country.
2011 Town and country doesn’t have a smart charge system like the vehicle I’m working on, on this video. What part of the us are you in ? I could direct you to a tech that I know that could perform a proper diagnostic
but I still can check alternator first using field wires?
EXCELLENT I live by Allen genoa/Spencer near your shop.
Awesome. Hey that’s for watching
I noticed that exact same problem on my Subaru, when I was trying to jumper lead charge my solar Batteries, then I noticed the Charge increase when I switched on my Park Lights.
Didn't know they do that but also you can graph the connector on the alternator to see the duty cycle
Have town and country 2011 and replaced battery and alternator but still not getting power to battery is there something else I am missing?
Check large amp fuse for Alternator in fuse box
@@jrivas7822 I don’t there is one
Alternator diodes keep going bad on Dodge Grand caravan 2012. Any ideas why???
Part of the "squeeze every mile/km out of that gallon/liter of gas" computer programming. Depending on the type of battery, it may also give longer battery life.
Looks like a good method of controlling battery charging but this needs to be in the owner's manual: "Battery voltage is not always 13.8 volts. It varies with the electrical load and the battery's state of charge. Voltages of 12.5 to 14.4 are normal when the engine is running."
Me? I've built a couple of small solar systems (shed lighting, "Wait until daylight" backup power) so I'm very aware of the trade-offs in battery charge level versus battery life. My previous set of AGM batteries (typical life of 5-7 years) were replaced a few months before their 9th birthday.
By the way, the car is equipped with stop/start system? If yes, then that is the normal behaviour of the alternator. My Renault from 2014 also acts like this, it goes to about 14 volts only when the headlights are on so when an important load is present.
Great work man. It’s funny that we’ve had smart alternators for quite some time but people still don’t realize it. Superb explanation of the system and showing how it works. One question I have. Did the versus not have the PIDs for duty cycle?
That is right. The verus only showed desired, not the actual duty cycle
What was the issue then
In the issue customer thought that because the battery was charging at 12 volts at idle that the alternator was bad. The thing is I found that this car is has smart charge and I performed test that showed 12v at idle is normal. Did you see that part of the video ?
Great video, just curious was the customer changing the Alternator based off of just the voltage readings? Or could there be a Parasitic draw?
I believe the first problem was an alternator. But after the new alternators were installed he would check the voltage and notice it would be 12 volts and he would take it back to get it replaced
@@OzMechanics well I guess we all have to learn the hard way. I got caught on my honda with this issue as well, change the Alternator and battery bc they were both bad and had the same readings and started testing based of of the readings, bench tested the Alternator and said hmmm...so I went and used my buddy subscription to pro demand and learned about smart charging. The vehicles are becoming to smart..IMO making them stupid lol. Thanks for what you do!
@@richardmitchell7836 yep, that’s how I learned about this. Honda
Had same issue on my truck come to find out the amps on the alternator that parts store gave me didn't match the amps for my truck as per Haynes manual putting more higher amp alternator won't make light of check charging system turn off putting the required correct amp alternator worked light turned off.
Good video, I actually learned something new today 😳
Thanks for watching
Wud that battery light on discharge the battery at night time as it sits?
Likely a problem with the ELD?
Did you watch the entire video ?
@@OzMechanicsYeah, I did.
Great video and great job doing thorough tests and research on a customer complaint.
It's just that I think a faulty ELD will make the ECU command a lower duty cycle (or higher, sometimes). There have been such cases on some Honda's.
So, maybe a research on the ELD signals could be for another video?
Just a suggestion.
Cheers.
I have a 2018 Durango and I had electrical issues. First the main battery went dead no start no crank. Apparently the auto stop/start battery was already dead. The dealership couldn’t find the problem. Second visit they found the stop/start battery was officially diagnosed dead. 230$ later the system worked. Then the main battery went dead again. Diagnosed as a dead cell and was replaced 460$. Now the alternator under acceleration load will drop to 12.8. No load coasting 14.5 same at idle. Chrysler said this is normal logic from the ECM. To me it seems counter intuitive
Damn bro, you saved me from changing my alternator from a 2nd time! I just got my alternator rebuilt and was about to take it back because I wasn’t getting a higher voltage than 12.5 until I did the battery load test and the voltage started going up like the video. I got a Honda accord 2016. What Honda were you referring too?
Awesome 😎 glad this video helped you out. I believe it was a Hyundai Electra if I’m not mistaken. Yea, these smart charge systems can take you on a loop. Thanks for watching
My check charging system is on in my 2012 civic si. I replaced the alternator and it fixed it for 3 months and then came back on and now can't drive it . Keeps not charging my battery
OZ, AWESOME it is great and the right way first to do ur basic checks as u did and read the info to verify the way system work thanks for sharing brother.cheeeeers
I have a 2013 avenger it won’t stay on after I jump start it.. I called the dealer & they told me the car should still run after jump starting it but the battery is so dead advanced auto reading came back with no Cranking amps. I’ve changed the alternator twice & still have this problem
i think what you did would help my problem.....but I dont understand what you did! My Jeep is acting like the alternator is bad but I have no codes!! Did you actually do anything?? I checked the throttle body and it does need cleaning bad! I didnt have enough cleaner to clean it good. Maybe thats the only problem. But if youre saying the alternator adapts to the situation,that helps.
Yes like on the video explained. When the vehicle is in idle with no load the alternator is only pulling around 12 volts but as soon as we put load to the vehicle exp turn ac on or headlights the computer commands the alternator to push 14 volts. This was a test showing that the vehicle was working as intended. As well we pulled out service information for that vehicle which also showed the operations. So I’m confused as when you asked if I actually did anything
Is this whats called a variable speed alternator??
Interesting troubleshooting and analysis of the data. What started all the replacement alternators in the first place ? Customer measuring the 12.3 V and then assuming that’s a problem?
The first time they replaced the battery, I’m sure it was probably because of a bad alternator. But the customer ended up telling me later on that he checked it out because his battery was drained, but told me that he believed he left the lights on. I verified That with a parasitic draw test and also the alternator test that was done on the video.
@@OzMechanics Thanks for your follow up reply. I have a 2015 Accord and connecting my DMM a few times noticed similar voltage readings. Didn’t realize PCM controls alternator voltage with newer cars.
PMC on 2003 mini cooper
Since our cars have computers nowadays and those computers can be accessed through OnStar can dealerships send false codes to our cars and trucks for us to bring them in for maintenance
That would be a big negative.
Great video Oz, this is the 1st alternator video I've ever seen on RUclips indicating ~ 12.4 Vdc at Idle. I believe most of the Alternator videos I've seen would have called this a Bad Alternator, do you know if a 2006 Toyota Tundra would operate like this Hyundai, i'm always monitoring the Alternator voltage and it seems Low ~ 12.6 to 12.4 at idle but when cruising and off idle voltage jumps up to 13.6 to 14.1. Thanks again for your video.
Great video, Thanks for posting!
Thanks for watching
Great vid!! Oz is in SnapOn and Autel heaven. Nice place to b. Lol
Bravo. nice video. Thanks for sharing your knowledge.
Thank you for watching
Nice demonstration of an on-demand alternator. Makes sense, really. Why waste power unnecessarily?
can a loose or faulty ground cable lessen the life of an alternator?