What a great topic, and a fine explanation! I find dealer repair manuals too thin to properly explain how some of these systems work, and they seem to intentionally leave important proprietary details out. They often leave out so much info that it is hard to use a logical approach to diagnostics. What I find most annoying is how they put huge effort into fuel economy, with no regard for how durable their product is. If the vehicle hits the landfill years sooner, corporate profits may be preserved but all environmental benefits are lost.
Thank you Dave and hoping you and the family are doing well! Yes, you are correct that it's hard to sometimes figure out how some of these systems work. And it makes it even harder to come up with a diagnostic plan of how to check the system if you don't know how it works. Thanks for dropping in and sharing a comment!
Great video Terry! I have a much better understanding of the system now. I have been troubleshooting my daughter’s 2013 Ford Escape and have been trying to educate myself on the electrical system; your video is the best I’ve found so far. She is having an issue with the alternator putting out too much voltage. It doesn’t seem to happen in the summer months, but it causes issues when it gets cold. The voltage will peak in the low 17v range and it’s high enough that it will turn off multiple modules in the car (4x4, ABS, speedometer, etc). With the plug disconnected from the alternator, it supplies 13.5-14v to the battery, indicating that the alternator itself and the default circuitry of the regulator is working correctly. The problem I’m running into is determining the root cause of the high voltage. Based on your slide, even at a 95% duty cycle, 17v shouldn’t be possible. Is it possible for the PCM to command more than 95%? If so that could mean the PCM is getting an erroneous input (BCM issue, or some other sensor issue). If not, then the PCM could be messed up and commanding what it shouldn’t, or it’s commanding what it should and the regulator is misinterpreting it and commanding too much voltage out of the alternator. How would you proceed, given this information? As a side note, I replaced the battery without change. Thank you!
Getting 17V is pretty high. Take a scanner and look at the GENCOM and GENMOM values in the PCM to see what they are saying. With the scanner still hooked up and the ignition switch OFF, disconnect the three pin connector at the alternator. Place a jumper between the GENCOM and GENMOM terminals. BE ABSOLUTELY SURE TO CONNECT THE CORRECT WIRES AS THERE IS ALSO THE B+ SENSE WIRE, WHICH YOU DON'T WANT TO CONNECT. Look at a wiring diagram for your car to be sure. Turn the ignition switch to ON and monitor the previous mentioned PIDs and you will see that that one will go up and a moment later, the other will go down. A moment later, the other PID will come back to life and other will shut down. This will continue until you disconnect the jumper. This proves that the PCM is communicating, the wires are OK and that the program inside the PCM is doing what it's supposed to do. You could also take a look at the waveforms and see what the duty cycle is at the three pin connector. Of course, be sure that you have the B+ sense voltage there too and that you've gone through checking for voltage drops between the battery ground, alternator case and between the B+ on the battery and the B+ terminal at the alternator. Just from your description, it sounds like the alternator is the culprit. But, diagnose it first before changing it.
Your wife might of thought it was boring but this video is extremely informative. Thank you so much. Thank you for sharing the conversion formulas and thanks for explaining these new starting systems. I noticed that sometimes you used the word generator and at another point the word alternator? Can you explain that? Thanks again I’m just a retired aircraft mechanic but now trying to study and learn todays cars new electrical systems. Taking courses wherever I can. Thanks for ATG, Mechanic mindset and Hands on Automotive Training plus let’s not leave out Mr.G at ATTS. Excellent courses. 👍
Hello Arthur and glad to hear that you found the video helpful. And guess what, the wife and I did a final preview before I uploaded the video, and she said that it was still boring 😂 Good to hear that in your retirement years, you're learning about automotive electronics and how they work. Always good to keep the brain working on something in our older years 😊 Yes, I use the terms alternator and generator interchangeability where it's a device which converts mechanical energy into the electrical energy. If you may remember in the old days like early 60s and before, the device was called a generator and this is where the brushes inside rode on top of a commutator which supplied current directly to the armature windings. The commutator was used to convert the AC into DC. Then in later years, the device was called an alternator which used diodes to convert the AC to DC. In 1996, the automotive industry decided to drop the term alternator and go back to being called generator. See, how confusing this is. Whether you call it a generator or alternator, people will know what you're talking about. For a little more technical aspects of the definition of alternator and generator, here is a link which can provide some more information on the topic. www.beupp.com/generator/what-is-the-difference-between-an-alternator-and-a-generator/ Have a great day and keep studying as it looks like you picked some fine resources to further your knowledge of the automotive industry. Have a great day!
@@stuzman52 thank you for the outstanding answer. I will definitely refresh my memory by watching the next video. Sounds like we’re from the same era and don’t ever want to stop learning. Thank you and once again tell the boss the video was filled with knowledge Lol Artie 👍
@@arthurfricchione8119 You are quite welcome Artie, and I asked the wife again about the video and she said that it wasn't quite as boring as the first draft 🤣, but still not her cup of tea. Always learn what you can no matter what the topic, and you'll be enriched with knowledge that can inspire you and your family for a more richer life. Thanks Artie for the support and have a blessed day!
Excellent video one of the very best instructional videos out there I subscribed immediately thank you for taking the time and sharing your knowledge with the rest of us. I finally feel as though I truly understand the ford smart charging system in detail
Great video..!! Very informative.! Especially when you don't have a scope. And also that conversion chart is very helpful. Thanks again for this informative video.
Yes, you are correct Bernarda that all of the systems are very similar and understanding one system makes it easier to understand another. Thanks for dropping in and sharing a comment!
Terry nice vid very informative and detailed I’ve got an 09 edge changed the generator in 2020 found the problem after checking all 12 diodes found 4 positive diodes were open thinking the cause was engine soak (heat) anyway that’s my 2 cents CHEERS
Outstanding informative video. Appreciated the time spent on explanation. I will try out my pico scope on my failed mustang to confirm the control side of pcm to alternator. Thanks, Russell, Qatar
@@russellmaguire-g1i With both of these signals whether it's the GENCOM or GENMON, they are both ground side switched. Not quite sure what your question is asking whether it makes a difference if they are ground side switched. If they were switched on the positive side, the PCM would be programmed to recognize that the signals would be energized when it's switched in a positive state. And as you may already know, when a signal is ground side switched, the signal is in an energized state.
@@stuzman52 hi thanks for response. As an example to try explain what i mean - if a scope is showing 75% duty cycle but the switching is ground side, does this mean its actually 25% duty cycle
@@russellmaguire-g1i Well, I guess it would depend on the scope of how it's measuring the duty cycle. As an example, let's use the picoscope. If you were to measure the waveform using the measurements tool, it would measure the high portion of the waveform as the on time even though it could be ground side switched. As in your example, the scope could measure 75% duty cycle, but in reality, it's 25% duty cycle since it's ground side switched. If you know beforehand that it's ground side switched, you can in use the math channel in picoscope to get a direct measurement of this 25% duty cycle. You would set the math channel as duty(-A) where the - sign tells the scope that you want to look at the lower part of the waveform as the on time. As a side note, if you were to use a DVOM which has the function of measuring the duty cycle, it would always measure the high portion of the waveform as being on even if it's a ground side switched circuit. If you're interested, I did two videos on PWM and go into quite a bit of detail on the subject. The first video is located here: th-cam.com/video/BLCSxkBvL2k/w-d-xo.html And the second video is located here: th-cam.com/video/OfRj9FGt__I/w-d-xo.html Have a great day!
What was the issue with the vehicle where the genmon signal was stuck at 100%. My vehicle is having the exact same problem and this is the first good source that has explained my situation.
In my case, the generator was at fault. If you want to see what's involved with replacing it, I did a video on a Ford Edge. Here is the link if you're interested. th-cam.com/video/QYYMyrMNEuE/w-d-xo.html Have a great day!
I have a 2019 escape titanium with the 2.0 engine. Here for a few weeks the car has been very briefly jerking and bucking sometimes intermittently. One time when it happened it quickly flashed the red engine oil light but the oil level was fine. Recently when at a light I went to go and it stalled and an auto stop start warning came up saying to put it in park to restart and I got it going again but it shut off again soon after in a parking lot. I turned off that feature and it has not stalled since. I ran a scan tool and it had some P06a7 code that mentioned something about the 5V reference voltage for the B circuit. I disconnected my battery overnight and I drove it 2 days since with no bucking and no codes except for one code that comes up for the radio even though the radio works, U0184. It had that code prior to battery disconnect too. Using my scan tool I live monitored the control module voltage and it’s all over the place. I have not used stop start since but the voltage with the vehicle off is about 12.3V. When running at first it’s about 14.8V but then it drops back to be about 13.6V most of the time. However, since monitoring this it shows the voltage range and I have seen the range show as low as 0.07V to as high as 58V so something is not right. I’m wondering if this is a potential issue with the voltage regulator in the alternator or possibly a PCM issue? The battery holds charge. The car has just under 69,000 miles on it and is garage kept year round. I think all of my issues are related to this erratic voltage. Not sure why there’s been no problem since the battery disconnect unless having the start stop turned off is preventing the prior issues. Ever see this kind of issue?
I have a question for you if you wouldn't mind. I have a 2014 ford edge sport with the 3.7L. I believe the charging system is identical, even and alternator. I'm upgrading my car audio system and one of the upgrades will be larger diameter power, ground, and charging wires. Will changing the diameter of the alternator charging wire negatively effect how the charging system functions or reacts? Thanks for your time.
Enlarging the wires to handle more current will not hurt the charging system. Keep in mind that if you're adding an audio system that will handle a significant amount of increased current, you need to be sure that the alternator can be able to supply the extra demand of current.
I understood most of the PWM aspects of these systems Terry but what exactly did you use to confirm that the alternator was bad? To most people that's the only question that needs to be answered. Obviously, if the battery is dying that's one hell of a clue but since the voltage is constantly being varied the old standard of "if it's above 13.5V then the alternator is doing it's job" is a lot harder to determine. So what's the magic bullet that confirms a dead, or dying alternator?
Hi Dennis! Well, of course if you don't see any battery charging voltage, that's an indicator that the battery isn't charging. But on the other hand, you may see charging voltage as you indicate, and there could still be a problem. I've see where there is a charging voltage and yet the charging indicator light is on. At this point, I would assume that there is an issue with the pulses sent or received by the PCM which for the most part would still be a fault of the generator. I can remember Eric O. doing a diagnostics on a Ford with this system and there was no charging voltage. Yet, the charging indicator never came on, even with the 3 wire connector disconnected from the generator. In my case, as I mentioned in the video, I would love to have seen the raw data on the scope while driving the vehicle. The problem was intermittent and I could never get it to fail while in the garage after about an hour of running while turning on loads, etc. And as I mentioned in the video, I didn't want four probes hooked up to get caught in the fan while driving. That's where I relied on the scanner data while driving which showed that the regulator stopped reporting the duty cycle on the GENMON line. So, I pretty much relied on the scanner data to call the generator the fault. Thanks Dennis for dropping in and sharing a comment! Have a great day!
@@stuzman52 Terry it might be time to come up with a third video: "How to Diagnose a Pulse Width Modulated Alternator." Your case here was exceptional since it was intermittent but that situation could be somewhat rare. Just a general video showing people what to look for to determine if their pulse width modulated alternators are working or not could be very helpful. We retired guys need something to do.
@@satamanschmidt3428 I figured that using a DVOM would point people in the right direction if their generator was working or not. Even at the end of the video, I mentioned about disconnecting the 3 wire connector and jumpering the GENCOM and GENMON lines together and monitoring those PIDs in a scanner to see if they would rise and fall which indicate that the PCM transmit and receive lines are not shorted or open and that the PCM with its algorithm are working. Not sure how much I could show.
Great video...I LOVE this guy and his teaching method....HOWEVER....To any engineer who may see this and had a hand in creating this system my question is WHY WHY WHY....Was this ridiculousness REALLY NECESSARY ??? I'm sorry you didn't get to work on the space shuttle program I REALLY am very sorry you felt your talents were being wasted but WHY WHY did you have to F ING over complicate this and SCREW OVER us everyday folks!!!....WHY ..?....To save a shot glass worth of fuel per 5 miles ???
Yes, if the alternator is capable of charging, it will do so without the connector. This is one of the steps for diagnosing the alternator. It should be around 13.5V. However, this does not mean the alternator is automatically good. The regulator inside the alternator could be bad which is controlled by the ECM.
Do you know where I can find a detailed Smart Charging System Diagram for my 2009 Ford Flex? I am having charging problems, I want to follow the COM line and MOD line for the PCM to the alternator, would like the pin # on the PCM, if possible, it would be a great help.
My 2009 Flex is not charging if I disconnect the alternator COM line and the MOD line, mine only has two lines on the back, should it change at 13.8 volts? newly rebuilt alternator and battery is very good, last time bothering you, thank you very much, John
@@mcfast52 Not sure why you would have only two lines and why they are called COM and MOD. The third wire would have been B+ sense. I guess they're doing something different with your system. If it's like the other generators using Ford's smart charging system, if you disconnect the connector and then rev the engine to about 2000 RPMs, the generator should put out about 13.8VDC. Have a great day!
@@stuzman52 I was mistaken, I just installed a new alternator and I like all the others it has three wires, with this new alternator everything is going well now the old rebuild did not work at all.
Seems to contradict what I am seeing after installing new alternator on 2003 Ford Expedition. GENCOM always displays a square wave typically around 8.6V, 60% duty cycle. GENMON shows around 8-9V DC return, no square wave. 14.2V at the battery. Connections between alternator and PCM check out at well under 0.5 ohms, no sign of wire chafing issues. PCM was swapped out, made no difference. OEM alternator was 2L7Z10346BA, replaced with Ultima R112019B. 1st replacement alternator showed a 170 Hz square wave. I thought it must be defective, returned and swapped. 2nd replacement alternator about the same result except 130 Hz square wave. So why a DC return on GENMON instead of a square wave?
Hi Steven, the GENMON will only put out a square wave pulse when it wants to change the setpoint. Otherwise, say after a start-up, you'll see activity on this line. Once the setpoint is made, you'll see a few pulses every 5 seconds or so. However, the GENMON line should always put out a square wave indicating the load on the alternator which reports back to the PCM. What's interesting is that you have 14.2V at the battery implying that the alternator is charging the battery. I would never check the ohms of wires as the only thing that it tells you with certainty is that the wire(s) are not open. I mentioned in the last part of the video of how to verify the wiring of these two wires and that the PCM is working correctly. First, to verify that the alternator will put out a charging voltage is to unplug the connector. Start the engine and rev it to around 2500 RPM and you should see about 13.5VDC at the battery. Now to check the wiring of the GENCOM and GENMON wiring and the PCM. With the connector at the generator still unplugged and the engine off, put a jumper between the GENCOM AND GENMON lines. Hook up your scanner and monitor the PIDs GENCOM and GENMON while the engine is running. You should see the GENCOM and GENMON PIDs flip-flopping. In other words, you'll see the GENCOM active and then the GENMON go inactive. And the process will repeat. If you see this, you know the lines are good, the PCM is good and that the program inside the PCM is doing its job. Good luck and have a great day!
@@stuzman52 Thanks very much for your reply. All this started when my battery warning light kept coming on and off randomly and I got a "Check Charging System" message, scan code P0620. Tried 2 rebuilt, reprogrammed PCMs, no difference. First rebuilt alternator produced similar measurements except GENCOM frequency was 170 Hz, GENMON voltage 8.8 V. Here are my detailed measurements with the 2nd alternator: A. 3-pin connector detached from alternator, measured at PCM Key off, ohms to GND at PCM: GENCOM = 2.1k GENMON = 134k Key on, engine off: GENCOM = 8.7 V DC GENMON = 0.0 V DC BAT = 12.16 V Key on, engine on at idle: GENCOM = 8.6 V DC GENMON = 11.6 V DC BAT = 11.82 V After engine rev to 2500 RPM: BAT = 14.29 V
B. 3-pin connector attached to alternator, measured at PCM Key on, engine off: GENCOM = 8.7 V DC GENMON = 0.0 V DC BAT = 12.17 V Key on, engine on at idle: GENCOM = square wave, ~9 V Pk to Pk, 133 HZ, ~60% +cycle GENMON = 10.4 V DC BAT = 14.19 V Turn A/C on: GENCOM DC = 5.8 V GENMON = 10.3 V DC BAT = 14.12 V Turn headlights on: GENCOM DC = 4.9 V GENMON = 10.2 V DC BAT = 13.97 V
Here is what makes no sense to me, based on your presentation and REMY's: Why does GENMON show a DC voltage instead of a square wave, and only when the engine is running? I thought this voltage was supplied by the PCM, to be manipulated by the alternator.
Why did the GENCOM square wave show a radically different frequency from the 1st alternator to the 2nd allegedly identical alternator? I thought this was controlled by the PCM, but it looks as if it is being set by the alternator.
Why does GENCOM show an 8.7 V DC level with the engine off and the alternator disconnected? I thought the GENCOM voltage was supplied by the alternator, then manipulated by the PCM.
With the alternator disconnected, key on, engine off, I would expect to see a source voltage at GENMON, and no voltage at GENCOM. Instead I see the opposite.
Even so the system seems to be charging the battery OK, and I have not (yet) seen the battery warning light come on since installing the 2nd alternator. Expedition was made in July 2003, but wiring appears to match 2004 wiring diagram, with no fuse in #9 (ALT) fuse location even though 2003 handbook says there should be a 10 Amp fuse there. I am wondering if I might have a Group 2 system as described in this article? www.electricalrebuilders.org/techlib/tech_articles/ford_6g_regulators.pdf
@@stevenlord7362 Hi Steven, the presentation I gave came from the website that I posted. I don't have any good answers for your data as it seems to be different between the two alternators. When I purchased the alternator, I was worried that I would get one that wouldn't work. And I'm sure that you've seen this from different distributors such as Napa, Auto Zone and others. And I had a friend with the same type of alternator order a brand new one from Amazon that didn't work. He finally got one from the junk yard which worked fine. Since your alternator seems to be working, I wouldn't worry about it. Do you have a scope to see the raw data that's on the three pin connector? Have a great day!
@@stuzman52 Thanks again. I do have a scope, can't understand why GENMON is always a DC voltage, not a square wave. Wondering if I got 2 defective alternators in a row. Either that, or the system just doesn't work the way I thought it did.
@@stevenlord7362 Excellent that you have a scope Steven! First, from your previous comment, you posted a link to a possible scenario of where you may have a totally different system. Here's what I would do! I would want to know how does this system work on my vehicle. I suggest a subscription to www.alldatadiy.com to read up on how this system works on my vehicle. For a month's subscription, it's $19.99 which is well worth the information that you need. My guess is that you have the system where there should be a square wave on the GENMON line at all times to report to the PCM how much load is on the generator. Read up on your system and if is like the system outlined in this video, then hook up your scope on the GENCOM and GENMON lines and see if you get the square waves. And while I'm thinking of it, did you jump the GENCOM and GENMON terminals together in the connector and monitor those PIDs as I mentioned in the previous comment? And do you have any battery charging issues, battery messages, etc.? And who knows, you may very well have another bad generator. I've seen several videos on TH-cam where users have changed their generators several times for not charging. Let me know what you see on the scope. Have a great evening!
Good question! The PCM tells the generator what it wants the generator to put out for current. At startup, the battery would be discharged, so you would see a lot of activity on the GENCOM line because it's telling the generator to output current to recharge the battery. Once the battery is charged, the GENCOM line would be mostly inactive except for the brief pulses to periodically send out a burst of current from the generator to keep the battery charged. Have a great evening!
What a great topic, and a fine explanation! I find dealer repair manuals too thin to properly explain how some of these systems work, and they seem to intentionally leave important proprietary details out. They often leave out so much info that it is hard to use a logical approach to diagnostics. What I find most annoying is how they put huge effort into fuel economy, with no regard for how durable their product is. If the vehicle hits the landfill years sooner, corporate profits may be preserved but all environmental benefits are lost.
Thank you Dave and hoping you and the family are doing well! Yes, you are correct that it's hard to sometimes figure out how some of these systems work. And it makes it even harder to come up with a diagnostic plan of how to check the system if you don't know how it works. Thanks for dropping in and sharing a comment!
This video is awesome. Far from boring. Thank you for your explanation. It’s very interesting to say the least.
Thank you Trevor for the comment and for watching! Have a great day!
Great video Terry! I have a much better understanding of the system now. I have been troubleshooting my daughter’s 2013 Ford Escape and have been trying to educate myself on the electrical system; your video is the best I’ve found so far. She is having an issue with the alternator putting out too much voltage. It doesn’t seem to happen in the summer months, but it causes issues when it gets cold. The voltage will peak in the low 17v range and it’s high enough that it will turn off multiple modules in the car (4x4, ABS, speedometer, etc). With the plug disconnected from the alternator, it supplies 13.5-14v to the battery, indicating that the alternator itself and the default circuitry of the regulator is working correctly. The problem I’m running into is determining the root cause of the high voltage. Based on your slide, even at a 95% duty cycle, 17v shouldn’t be possible. Is it possible for the PCM to command more than 95%? If so that could mean the PCM is getting an erroneous input (BCM issue, or some other sensor issue). If not, then the PCM could be messed up and commanding what it shouldn’t, or it’s commanding what it should and the regulator is misinterpreting it and commanding too much voltage out of the alternator. How would you proceed, given this information? As a side note, I replaced the battery without change. Thank you!
Getting 17V is pretty high. Take a scanner and look at the GENCOM and GENMOM values in the PCM to see what they are saying. With the scanner still hooked up and the ignition switch OFF, disconnect the three pin connector at the alternator. Place a jumper between the GENCOM and GENMOM terminals. BE ABSOLUTELY SURE TO CONNECT THE CORRECT WIRES AS THERE IS ALSO THE B+ SENSE WIRE, WHICH YOU DON'T WANT TO CONNECT. Look at a wiring diagram for your car to be sure. Turn the ignition switch to ON and monitor the previous mentioned PIDs and you will see that that one will go up and a moment later, the other will go down. A moment later, the other PID will come back to life and other will shut down. This will continue until you disconnect the jumper. This proves that the PCM is communicating, the wires are OK and that the program inside the PCM is doing what it's supposed to do. You could also take a look at the waveforms and see what the duty cycle is at the three pin connector. Of course, be sure that you have the B+ sense voltage there too and that you've gone through checking for voltage drops between the battery ground, alternator case and between the B+ on the battery and the B+ terminal at the alternator. Just from your description, it sounds like the alternator is the culprit. But, diagnose it first before changing it.
Thanks for a great description of operation far better that what Ford Motor Company give out in their training information
Thank you very much Paul and have a great day!
Your wife might of thought it was boring but this video is extremely informative. Thank you so much. Thank you for sharing the conversion formulas and thanks for explaining these new starting systems. I noticed that sometimes you used the word generator and at another point the word alternator? Can you explain that? Thanks again I’m just a retired aircraft mechanic but now trying to study and learn todays cars new electrical systems. Taking courses wherever I can. Thanks for ATG, Mechanic mindset and Hands on Automotive Training plus let’s not leave out Mr.G at ATTS. Excellent courses. 👍
Hello Arthur and glad to hear that you found the video helpful. And guess what, the wife and I did a final preview before I uploaded the video, and she said that it was still boring 😂 Good to hear that in your retirement years, you're learning about automotive electronics and how they work. Always good to keep the brain working on something in our older years 😊 Yes, I use the terms alternator and generator interchangeability where it's a device which converts mechanical energy into the electrical energy. If you may remember in the old days like early 60s and before, the device was called a generator and this is where the brushes inside rode on top of a commutator which supplied current directly to the armature windings. The commutator was used to convert the AC into DC. Then in later years, the device was called an alternator which used diodes to convert the AC to DC. In 1996, the automotive industry decided to drop the term alternator and go back to being called generator. See, how confusing this is. Whether you call it a generator or alternator, people will know what you're talking about. For a little more technical aspects of the definition of alternator and generator, here is a link which can provide some more information on the topic. www.beupp.com/generator/what-is-the-difference-between-an-alternator-and-a-generator/ Have a great day and keep studying as it looks like you picked some fine resources to further your knowledge of the automotive industry. Have a great day!
@@stuzman52 thank you for the outstanding answer. I will definitely refresh my memory by watching the next video. Sounds like we’re from the same era and don’t ever want to stop learning. Thank you and once again tell the boss the video was filled with knowledge Lol Artie 👍
@@arthurfricchione8119 You are quite welcome Artie, and I asked the wife again about the video and she said that it wasn't quite as boring as the first draft 🤣, but still not her cup of tea. Always learn what you can no matter what the topic, and you'll be enriched with knowledge that can inspire you and your family for a more richer life. Thanks Artie for the support and have a blessed day!
Excellent video one of the very best instructional videos out there I subscribed immediately thank you for taking the time and sharing your knowledge with the rest of us. I finally feel as though I truly understand the ford smart charging system in detail
Glad to hear that you found the video helpful! Have a great day!
Excellent tutorial. Thanks for taking the time to make such a detailed video. Terry for President! haha
Thank you Glen for dropping in and sharing a comment! HaHa, me for President! That will be the day 😂
Great video..!! Very informative.! Especially when you don't have a scope. And also that conversion chart is very helpful. Thanks again for this informative video.
Thank you very much for the comment Arthur and wishing you and your family a Happy Thanksgiving!
Great video, this same concept helps to understand other car makers like Honda's smart system w/ an Electrical Load Detector!
Yes, you are correct Bernarda that all of the systems are very similar and understanding one system makes it easier to understand another. Thanks for dropping in and sharing a comment!
Good job. Have a blessed week to you and your family.
Thank you Billy! And wishing you and your family a blessed week also! Have a great evening!
Terry nice vid very informative and detailed I’ve got an 09 edge changed the generator in 2020 found the problem after checking all 12 diodes found 4 positive diodes were open thinking the cause was engine soak (heat) anyway that’s my 2 cents CHEERS
Thank you Anthony for sharing a comment! Good to hear that you got your generator sorted out and have a great day!
Outstanding informative video. Appreciated the time spent on explanation. I will try out my pico scope on my failed mustang to confirm the control side of pcm to alternator. Thanks, Russell, Qatar
Thanks for watching the video and for the comment! Good luck on your project!
One question for my better understanding - the duty cycle - does it make a difference if the signals are ground switched?
@@russellmaguire-g1i With both of these signals whether it's the GENCOM or GENMON, they are both ground side switched. Not quite sure what your question is asking whether it makes a difference if they are ground side switched. If they were switched on the positive side, the PCM would be programmed to recognize that the signals would be energized when it's switched in a positive state. And as you may already know, when a signal is ground side switched, the signal is in an energized state.
@@stuzman52 hi thanks for response. As an example to try explain what i mean - if a scope is showing 75% duty cycle but the switching is ground side, does this mean its actually 25% duty cycle
@@russellmaguire-g1i Well, I guess it would depend on the scope of how it's measuring the duty cycle. As an example, let's use the picoscope. If you were to measure the waveform using the measurements tool, it would measure the high portion of the waveform as the on time even though it could be ground side switched. As in your example, the scope could measure 75% duty cycle, but in reality, it's 25% duty cycle since it's ground side switched. If you know beforehand that it's ground side switched, you can in use the math channel in picoscope to get a direct measurement of this 25% duty cycle. You would set the math channel as duty(-A) where the - sign tells the scope that you want to look at the lower part of the waveform as the on time. As a side note, if you were to use a DVOM which has the function of measuring the duty cycle, it would always measure the high portion of the waveform as being on even if it's a ground side switched circuit.
If you're interested, I did two videos on PWM and go into quite a bit of detail on the subject. The first video is located here: th-cam.com/video/BLCSxkBvL2k/w-d-xo.html
And the second video is located here: th-cam.com/video/OfRj9FGt__I/w-d-xo.html
Have a great day!
What was the issue with the vehicle where the genmon signal was stuck at 100%. My vehicle is having the exact same problem and this is the first good source that has explained my situation.
In my case, the generator was at fault. If you want to see what's involved with replacing it, I did a video on a Ford Edge. Here is the link if you're interested. th-cam.com/video/QYYMyrMNEuE/w-d-xo.html Have a great day!
Most informative, thank you. I learned a great deal from this video.😃
Thank you Labrador and glad the video helped. Have a great day and don't work too hard!
Great video. Very informative. Thanks again.
Glad to hear that you found the video helpful and informative. Have a great day!
I have a 2019 escape titanium with the 2.0 engine. Here for a few weeks the car has been very briefly jerking and bucking sometimes intermittently. One time when it happened it quickly flashed the red engine oil light but the oil level was fine. Recently when at a light I went to go and it stalled and an auto stop start warning came up saying to put it in park to restart and I got it going again but it shut off again soon after in a parking lot. I turned off that feature and it has not stalled since. I ran a scan tool and it had some P06a7 code that mentioned something about the 5V reference voltage for the B circuit. I disconnected my battery overnight and I drove it 2 days since with no bucking and no codes except for one code that comes up for the radio even though the radio works, U0184. It had that code prior to battery disconnect too. Using my scan tool I live monitored the control module voltage and it’s all over the place. I have not used stop start since but the voltage with the vehicle off is about 12.3V. When running at first it’s about 14.8V but then it drops back to be about 13.6V most of the time. However, since monitoring this it shows the voltage range and I have seen the range show as low as 0.07V to as high as 58V so something is not right. I’m wondering if this is a potential issue with the voltage regulator in the alternator or possibly a PCM issue? The battery holds charge. The car has just under 69,000 miles on it and is garage kept year round. I think all of my issues are related to this erratic voltage. Not sure why there’s been no problem since the battery disconnect unless having the start stop turned off is preventing the prior issues. Ever see this kind of issue?
With voltages swinging from 0.07V to 58V, I would definitely look into the charging system.
Great video , any chance to get your PowerPoint presentation emailed ?
Great video and explanation thank you.😁
Thank you Lynne for watching and sharing a comment! Have a great day!
I have a question for you if you wouldn't mind. I have a 2014 ford edge sport with the 3.7L. I believe the charging system is identical, even and alternator. I'm upgrading my car audio system and one of the upgrades will be larger diameter power, ground, and charging wires. Will changing the diameter of the alternator charging wire negatively effect how the charging system functions or reacts? Thanks for your time.
Enlarging the wires to handle more current will not hurt the charging system. Keep in mind that if you're adding an audio system that will handle a significant amount of increased current, you need to be sure that the alternator can be able to supply the extra demand of current.
Can you help try to keep voltage at 14.4 to 13.8 all the time 2020 mustang gt? Thanks
I understood most of the PWM aspects of these systems Terry but what exactly did you use to confirm that the alternator was bad? To most people that's the only question that needs to be answered. Obviously, if the battery is dying that's one hell of a clue but since the voltage is constantly being varied the old standard of "if it's above 13.5V then the alternator is doing it's job" is a lot harder to determine. So what's the magic bullet that confirms a dead, or dying alternator?
Hi Dennis! Well, of course if you don't see any battery charging voltage, that's an indicator that the battery isn't charging. But on the other hand, you may see charging voltage as you indicate, and there could still be a problem. I've see where there is a charging voltage and yet the charging indicator light is on. At this point, I would assume that there is an issue with the pulses sent or received by the PCM which for the most part would still be a fault of the generator. I can remember Eric O. doing a diagnostics on a Ford with this system and there was no charging voltage. Yet, the charging indicator never came on, even with the 3 wire connector disconnected from the generator. In my case, as I mentioned in the video, I would love to have seen the raw data on the scope while driving the vehicle. The problem was intermittent and I could never get it to fail while in the garage after about an hour of running while turning on loads, etc. And as I mentioned in the video, I didn't want four probes hooked up to get caught in the fan while driving. That's where I relied on the scanner data while driving which showed that the regulator stopped reporting the duty cycle on the GENMON line. So, I pretty much relied on the scanner data to call the generator the fault. Thanks Dennis for dropping in and sharing a comment! Have a great day!
@@stuzman52 Terry it might be time to come up with a third video: "How to Diagnose a Pulse Width Modulated Alternator." Your case here was exceptional since it was intermittent but that situation could be somewhat rare. Just a general video showing people what to look for to determine if their pulse width modulated alternators are working or not could be very helpful. We retired guys need something to do.
@@satamanschmidt3428 I figured that using a DVOM would point people in the right direction if their generator was working or not. Even at the end of the video, I mentioned about disconnecting the 3 wire connector and jumpering the GENCOM and GENMON lines together and monitoring those PIDs in a scanner to see if they would rise and fall which indicate that the PCM transmit and receive lines are not shorted or open and that the PCM with its algorithm are working. Not sure how much I could show.
Thank you I liked it vary much
Thank you Mason and glad to hear that you liked the video! Have a great day!
Great video...I LOVE this guy and his teaching method....HOWEVER....To any engineer who may see this and had a hand in creating this system my question is WHY WHY WHY....Was this ridiculousness REALLY NECESSARY ??? I'm sorry you didn't get to work on the space shuttle program I REALLY am very sorry you felt your talents were being wasted but WHY WHY did you have to F ING over complicate this and SCREW OVER us everyday folks!!!....WHY ..?....To save a shot glass worth of fuel per 5 miles ???
Thank you Thomas for watching and have a great day!
Grand marquis 2001 alternator charging without plug?
Yes, if the alternator is capable of charging, it will do so without the connector. This is one of the steps for diagnosing the alternator. It should be around 13.5V. However, this does not mean the alternator is automatically good. The regulator inside the alternator could be bad which is controlled by the ECM.
@stuzman52 i have changed 3 alternator it all charging 13,0v and 2001 model charging system not related to the ECM
Do you know where I can find a detailed Smart Charging System Diagram for my 2009 Ford Flex? I am having charging problems, I want to follow the COM line and MOD line for the PCM to the alternator, would like the pin # on the PCM, if possible, it would be a great help.
I like to get my wiring diagrams from www.alldatadiy.com Have a great New Year!
My 2009 Flex is not charging if I disconnect the alternator COM line and the MOD line, mine only has two lines on the back, should it change at 13.8 volts? newly rebuilt alternator and battery is very good, last time bothering you, thank you very much, John
@@mcfast52 Not sure why you would have only two lines and why they are called COM and MOD. The third wire would have been B+ sense. I guess they're doing something different with your system. If it's like the other generators using Ford's smart charging system, if you disconnect the connector and then rev the engine to about 2000 RPMs, the generator should put out about 13.8VDC. Have a great day!
@@stuzman52 I was mistaken, I just installed a new alternator and I like all the others it has three wires, with this new alternator everything is going well now the old rebuild did not work at all.
@@mcfast52 Glad to hear that you got it all figured out and that your system is working now. Have a good one!
You Da Mayn Terry ❤️
Thank you Khanee and hoping you and the family are doing well!
@@stuzman52 Missing you as always
@@khaneemalone3793 Same here Khanee! Be sure to be safe in your travels.
Seems to contradict what I am seeing after installing new alternator on 2003 Ford Expedition. GENCOM always displays a square wave typically around 8.6V, 60% duty cycle. GENMON shows around 8-9V DC return, no square wave. 14.2V at the battery. Connections between alternator and PCM check out at well under 0.5 ohms, no sign of wire chafing issues. PCM was swapped out, made no difference. OEM alternator was 2L7Z10346BA, replaced with Ultima R112019B. 1st replacement alternator showed a 170 Hz square wave. I thought it must be defective, returned and swapped. 2nd replacement alternator about the same result except 130 Hz square wave. So why a DC return on GENMON instead of a square wave?
Hi Steven, the GENMON will only put out a square wave pulse when it wants to change the setpoint. Otherwise, say after a start-up, you'll see activity on this line. Once the setpoint is made, you'll see a few pulses every 5 seconds or so. However, the GENMON line should always put out a square wave indicating the load on the alternator which reports back to the PCM. What's interesting is that you have 14.2V at the battery implying that the alternator is charging the battery. I would never check the ohms of wires as the only thing that it tells you with certainty is that the wire(s) are not open. I mentioned in the last part of the video of how to verify the wiring of these two wires and that the PCM is working correctly.
First, to verify that the alternator will put out a charging voltage is to unplug the connector. Start the engine and rev it to around 2500 RPM and you should see about 13.5VDC at the battery.
Now to check the wiring of the GENCOM and GENMON wiring and the PCM. With the connector at the generator still unplugged and the engine off, put a jumper between the GENCOM AND GENMON lines. Hook up your scanner and monitor the PIDs GENCOM and GENMON while the engine is running. You should see the GENCOM and GENMON PIDs flip-flopping. In other words, you'll see the GENCOM active and then the GENMON go inactive. And the process will repeat. If you see this, you know the lines are good, the PCM is good and that the program inside the PCM is doing its job. Good luck and have a great day!
@@stuzman52
Thanks very much for your reply. All this started when my battery warning light kept coming on and off randomly and I got a "Check Charging System" message, scan code P0620. Tried 2 rebuilt, reprogrammed PCMs, no difference. First rebuilt alternator produced similar measurements except GENCOM frequency was 170 Hz, GENMON voltage 8.8 V.
Here are my detailed measurements with the 2nd alternator:
A. 3-pin connector detached from alternator, measured at PCM
Key off, ohms to GND at PCM: GENCOM = 2.1k GENMON = 134k
Key on, engine off: GENCOM = 8.7 V DC GENMON = 0.0 V DC BAT = 12.16 V
Key on, engine on at idle: GENCOM = 8.6 V DC GENMON = 11.6 V DC BAT = 11.82 V
After engine rev to 2500 RPM: BAT = 14.29 V
B. 3-pin connector attached to alternator, measured at PCM
Key on, engine off: GENCOM = 8.7 V DC GENMON = 0.0 V DC BAT = 12.17 V
Key on, engine on at idle: GENCOM = square wave, ~9 V Pk to Pk, 133 HZ, ~60% +cycle
GENMON = 10.4 V DC BAT = 14.19 V
Turn A/C on: GENCOM DC = 5.8 V GENMON = 10.3 V DC BAT = 14.12 V
Turn headlights on: GENCOM DC = 4.9 V GENMON = 10.2 V DC BAT = 13.97 V
Here is what makes no sense to me, based on your presentation and REMY's:
Why does GENMON show a DC voltage instead of a square wave, and only when the engine is running? I thought this voltage was supplied by the PCM, to be manipulated by the alternator.
Why did the GENCOM square wave show a radically different frequency from the 1st alternator to the 2nd allegedly identical alternator? I thought this was controlled by the PCM, but it looks as if it is being set by the alternator.
Why does GENCOM show an 8.7 V DC level with the engine off and the alternator disconnected? I thought the GENCOM voltage was supplied by the alternator, then manipulated by the PCM.
With the alternator disconnected, key on, engine off, I would expect to see a source voltage at GENMON, and no voltage at GENCOM. Instead I see the opposite.
Even so the system seems to be charging the battery OK, and I have not (yet) seen the battery warning light come on since installing the 2nd alternator.
Expedition was made in July 2003, but wiring appears to match 2004 wiring diagram, with no fuse in #9 (ALT) fuse location even though 2003 handbook says there should be a 10 Amp fuse there.
I am wondering if I might have a Group 2 system as described in this article?
www.electricalrebuilders.org/techlib/tech_articles/ford_6g_regulators.pdf
@@stevenlord7362 Hi Steven, the presentation I gave came from the website that I posted. I don't have any good answers for your data as it seems to be different between the two alternators. When I purchased the alternator, I was worried that I would get one that wouldn't work. And I'm sure that you've seen this from different distributors such as Napa, Auto Zone and others. And I had a friend with the same type of alternator order a brand new one from Amazon that didn't work. He finally got one from the junk yard which worked fine. Since your alternator seems to be working, I wouldn't worry about it. Do you have a scope to see the raw data that's on the three pin connector? Have a great day!
@@stuzman52
Thanks again. I do have a scope, can't understand why GENMON is always a DC voltage, not a square wave. Wondering if I got 2 defective alternators in a row. Either that, or the system just doesn't work the way I thought it did.
@@stevenlord7362 Excellent that you have a scope Steven! First, from your previous comment, you posted a link to a possible scenario of where you may have a totally different system. Here's what I would do! I would want to know how does this system work on my vehicle. I suggest a subscription to www.alldatadiy.com to read up on how this system works on my vehicle. For a month's subscription, it's $19.99 which is well worth the information that you need. My guess is that you have the system where there should be a square wave on the GENMON line at all times to report to the PCM how much load is on the generator. Read up on your system and if is like the system outlined in this video, then hook up your scope on the GENCOM and GENMON lines and see if you get the square waves. And while I'm thinking of it, did you jump the GENCOM and GENMON terminals together in the connector and monitor those PIDs as I mentioned in the previous comment? And do you have any battery charging issues, battery messages, etc.? And who knows, you may very well have another bad generator. I've seen several videos on TH-cam where users have changed their generators several times for not charging. Let me know what you see on the scope. Have a great evening!
Why is Gencom's waveform not continuous. most of the time is 0 percent. I mean only two green columns are showing
Good question! The PCM tells the generator what it wants the generator to put out for current. At startup, the battery would be discharged, so you would see a lot of activity on the GENCOM line because it's telling the generator to output current to recharge the battery. Once the battery is charged, the GENCOM line would be mostly inactive except for the brief pulses to periodically send out a burst of current from the generator to keep the battery charged. Have a great evening!
@@stuzman52 Thank you for your good explanation.Sir. You are so kind. Have a good weekend
@@yijianggu5203You are quite welcome my friend! Have a great day!
Great video , any chance to get your PowerPoint presentation emailed ?
Thanks Scott for the comment! I looked back at my flash drive backups and it appears that I didn't save it for future use. Sorry...