2004-2009 Toyota Prius High Voltage System Operation 

This gentleman is a world class teacher. I don't have a Prius, but after stumbling apon this video I just had to subscribe. The way the information is relayed to the viewing audience is as high a quality as the engineering in question. Respect.

You are absolutely brilliant, wonderful and very intelligent and calm person sir. This is absolutely free knowldge you are providing us. I am very grateful to you. I wish that i could be in your class to learn from you. I thank you so much for making all these videos.

This teaching setup is incredible! Thank you so much for taking the time to share this information us. The prius is such an incredible vehicle and this layout showcases the components so well!

John is brilliant. I work on these things and wish I could work with him on many of the issues I run into. Amazing WEALTH of knowledge and fantastic explanations. I've learned so much watching his videos and his breakdowns on how these Hybrid Synergy Drive systems work.

Good Morning! I am a Brazilian automotive specialist graduated from SENAI and General Motors Brasil! Weber, congratulations, excellent technical video! May God bless you and keep making other videos with this technical ability! Grateful Wilmar Ribeiro

This is well above my head and I will need to watch this couple of times. Very well presented and useful information!

Приус это шедевр! Высокий импульс творческой мысли, смелое шерение , чудесное поплощение!!! Быть добру!!! Таёта I LOVE YOU!

You encouraged me to work on inverter/converter unit on my 2007 Prius. Dealership wanted to charge me 5k for it but it cost me $300 on used unit. My Prius is almost 277, 000 miles and counting!!!! Thank you so much.

I do not know English very well, but I've seen many videos of you. You are an excellent and extremely professional teacher. For 3 or 4 years I subscribed to your channel and I liked all the videos I've seen. I work the electronics of the cars. I know something about robotics, mechanics, electronics. I think cars are robot with wheels. I like the electrics and I think the hybrids are a step to them and until the infra-structure is created so that we can all have an electric car, the hybrids are good. I had a 2006 Honda Civic Hibrid. I bought it in 250 dollars because they were going to join it. In a few hours I put it to work. Now I have a 2006 Toyota Prius. It does not work With what little I've seen, I've learned that it's very different from Honda. It has helped me a lot to see all your videos of the Toyotas II Generation. The high voltage batteries had 190 volts. They had a lot of sulfate in the contacts. I cleaned everything very well and now it has 201 volts. The scanner gives me two codes: 1) on the HV and it tells me to replace the Inverter-converter module. 2) Replace the battery. When I try to start the relay of the battery block sounds and in the dash it flashes READY 2 or 3 times and then the red triangle appears. I have another module inverter converter equal, but my question is whether it is the module or the batteries. I measure the voltage of them at the moment of starting and lowering something, but in a few seconds they return to 201 volts. I also want to know if the starter of this car is only for the MG1 or has an external one. I already learned with you that it has no alternator, which it does through the conversion of 201.6 to 12 in the inverter module of the A / C. I know that the Honda does have a starter, but it still does not. Please, I need your help. You can answer me in English and I use the google translator, but if you can send me some documentation in Spanish I would also appreciate it. Thank you very much for all your videos. I'm sure you help thousands of people around the world, because you do it with professionalism and love of what you do. Greetings from Tampa, Florida.

Wow, thank you! I already had some basic knowledge of hybrid vehicle technology, but this is the absolute best breakdown video I have ever watched! I now know exponentially more than I would have thought possible, and understand my car and it's operation. Thanks!

Excellent presentation and amazing engineering by Toyota. I just bought the 2008 Prius and wanted to learn more about the system.

Fantastic job my friend. Learned a lot on that electrical system. Gives me a way better understanding on how the car works

Outstanding demonstration for this HV. WSU Automotive Technology 'Great job'.

Danke für Ihre Arbeit, Herr Kelly. Sie sind ein fantastischer Lehrer. Thx for your work, Mr. Kelly. You are a fantastic teacher.

Thanks John! I'm thinking to buy an used 2nd gen Prius and with no knowledge on the area, as a simple potential car owner, I really appreciated your video made in simple words. Again thank you very much.

This was very informative, I really need full knowledge of all components and buttons in the jump start box!!

John, that clock says 11:25. It's either time for lunch or time for bed. Great video.

This is just great. Thank you very much for this awesome explanatory lesson. I watched this video twice, you are great. Thank you very much. I always thought that there is nothing free in US, i guess i'm wrong. This turned out to be very great free lesson on how hybrid system works. Really appreciate your time and effort on briefly explaining it how this system works. Great stuff.

Congratulation for the helpful explanation. It´s good to learn from another Professor.

this guy deserves money

Very informative video that demonstrate how the electric system works on a Prius. Thanks.

Thank you for this quality presentation. I hope you can follow up with more on internal components, things that might fail and what is involved to service them, especially failure mode(s) of the HV battery and reconditioning possibility.

Thank you Prof.......so amazing to learn how new electric vehicle built, I'm a electric reach truck technician so I can understand what you explain, God bless you even more Sir.....

Simply the best video, no comparison. This is truly professional.

Awesome terrific nice thanks for that beautiful information i appreciate your time you spend teaching us so important information God bless you and your family have a beautiful day!! Thanks

Amazing! So well explained. Thank You Professor. It is a marvelous travel trough my favorite vehicle.

Awesome. I teach wind turbine operations and had no idea how similar the Prius electrical system was to the asynchronous generators used on wind turbines.

That's the most comprehensive review I've found, good job. As a Lexus 400h owner, my experience has been mostly with the very small 12V battery. Because the large rear battery will not charge the 12V battery when key is off, you have to be careful not to run that little battery down. I've boosted a few times already and we have booster cables, which are unfortunately hard to get to because the trunk won't open with a drained accessory battery. Boosting is done in the usual way.

absolutely concise. loved it. 15 nuff nuffs showed their stupidity by thumbs downing this material. WHAAAAT?

Thank you sir,very informative! God bless!

thank you for detailed explanation of the toyota system . . . so very completely well understood . . .

Thank you sir, this is what I was looking for.

ThanK you so much... You're amazing and your explanations are quite unique and understandable... Thanks a bunch

Great effort. Thank you very much

0:00 I remember in one of your newest videos you talk about that red high voltage glove thats hanging on the wall. Its crazy how much it deteriorated over 7 years.

Many thanks indeed for this awesome video... 👌

excellent video , it make me aware of the parts of my Lexus ct which has the same engine as the Prius

Outstanding John. Thank you.

So cool! What a great teacher. Wish I could be a student here!

Take a breath! )) Great review though clear and accurate!

Excellent presentation. Thank you.

Awesome! Thank you for this.

Absolutely an awesome video. Thank you very much for this.

good evening or morning! i have highlander hybrid 3.300 front wheel drive and my ICE engine wouldnt stop when ideling! Gas engine never stalls although it should! Thank you.

Thanks for the detailed overview. In summary the system de-energizes itself but I wouldn't stake my life on it. Have you a video on the computer that controls the engine, MGs, and inverter/converter, accessory charger, etc? That must be the heart of the system!

Great information on the way to the last second!

Amazing layout wonderful knowledge simple straight to the point all amazing matainance tips and reminders

Excellent video. Thank you

@JrgrimWoW Hi, thank you. I must have forgotten to mention the "Flux Capacitor" and the "Jiga-Watts" of power. :)

Top notch explanation!

Extremely interesting and technically-oriented. Seeing the cut-aways and the cabling in real life sizes takes some of the mystery out of it. Thanks for showing us your setup. Students at your school should be able to learn about the Hybrid system very easily. BTW, you mentioned about never towing a hybrid vehicle. What does someone do if they need a tow? Call a flat bed truck?

Excellent video. Very informative.

Thanks for such a informative video

That's a very informative video, Thanks.

Bonjour, je suis très ravie de la vidéo , je vous remercie car vos explications sont très claires , je continue à vous suivre.

Thank you for the great video!

We work on hybrid at our shop, and we use Your illustration to explain to our mechanics, overall (block diagram) system,how to troubleshoot voltages and communications between computers ,Amazing Illustration, Good Job I would like to add a notice that if you decide to tow your vehicle you can use Wheel-lift towing as long front wheels they are not moving (Front wheel drive ),Kindly correct if I am wrong .

Thank you very much for this video! Wish chevy would do what toyota did and partner up with a university to teach its chevy volt system. But since they dont even post the volt's battery voltage on the wiki page i doubt that will happen anytime soon. Thanks again!

You rock homie. Thanks for this tutorial.

thank you for the vid...

Hi, No, the high voltage system is totally isolated from the 12V system. It is like a flashlight sitting on your back seat (it has its own isolated power supply).

Truly appreciated! Is there any high-voltage fuse protection for the Gen2 A/C compressor circuit?

Better than the wikipedia article, love it Only thing i cant find out anywhere is a power rating of the ac compressor

Its a great explanation. Thanks for the help

Excellence explanation video, thanks.

thank you so much for such for actually explaining this unit in such detail.

Excellent! Excellent! Thank you.

Your are great teacher thank you

Thank you sir valuable information

Excellent video! Would you recommend buying a hybrid vehicle for the average driver? What would be the criteria to whether buy a hybrid or not?

Hi, upon further investigation I have determined that you are correct, the labels are reversed. The second generation had two relays on the positive side and one on the negative. The third generation Prius is the opposite with two on the negative and one on the positive. I was also wrong on the contactor verses relay name. Toyota does call them System Main Relays (SMR), I think it is GM and/or Honda that call them contactors. So many different systems, yet all similar. Thanks again!

Hi! Great content.I would like to know, when working on deconnecting the high voltage power on the vehicle, which PPE should be used for this task? Rubber gloves? Goggles? Arc Flash clothing?thanks

Nice video. Tanks.

Hi Prof, as usual great video. Just wanted to check if there are no refrigerant in the air con pump will it throw a code? POAA6?

Thank you John D. Kelly at WSU for confirming my suspicion that the HV wiring labeling is incorrect. At 2:05 the labels should be swapped. The +ve cable being the short one and the -ve cable being the long one.

Very informative video. Have wondered about all of this for some time. Many thanks for your generosity. What an amazing vehicle. Mine is a 2007 model with 252,000km on the clock. All the best.

Great video!!! When replacing the transmission let's say, Is " removing the service plug grip" good enough to work under the hood? Thanks.

Vidéo passionnante (exciting video)

Many hybrids have jump start terminals under the hood (even if the battery is in the rear). You might check the owner's manual to see if your model does.

And the mistery is gone !!, Thankss a lot

Nice Job!

It's looks like Power Electrical. 3 phase Motor drives by VFD. Thank you Professor.

You are just fantastic, Sir. Im from Mauritius and I'll like to learn the hybrid batteries as I intend to offer hybrid battery service. Looking forward to talking to you. Thank you.

thank you for giving some knowledge

Excellent learning material.... I have watched your video many times despite the camera movement..I have learned a lot about hybrid electrical system...If you can only improve your video by using a tripod on your camera with an assistant to focus the camera on your visual materials, I'm sure , this will make WSU a big HIT on youtube like a blockbuster.. More power and million thanks.

Well done!

Great video,

great demonstration..Could you have the isolation relays wrongly labled.the arc aresting component on mine is across the positive isolation relay.

Thanks for that! Does it mean that they would be another inverter for rear motor on RAV4’s all wheel drive systems?

Thank You for this great video! Very nice job explaining the components. I have a question that I hope you either have knowledge of or can obtain. Can you tell me what the Kwh is of MG1 and what is the output current of MG1 when it is in regen mode? I realize that the power MG1 is generating is 3 phase which must be changed to DC to recharge the batteries. Just curious what Volts, Amperage is produced directly by MG1 if in fact it is similar to or greater than a standard alternator prior to being rectified. My guess is that MG1 produces more power output than a standard alternator.

Nice set up.

GREAT HELP. ONLY THANKS

Awesome thanks!

2005 Prius has a repetitive indication of a Hybrid Battery problem. I bought a rebuilt Hybrid Battery from a national auto parts company with a 3 yr warranty. Initially replaced the original prius Hybrid Battery and 12v battery in February of 2017. It appeared to resolve the problem. Three months later, in May of 2017, it indicated an OBDII code of P0A80 and I replaced the Hybrid Battery again under warranty. Both times the replacement battery worked well initially. But it rarely achieved 100%. Usually the dash indicated 80% at best. Two weeks ago, I got the red triangle and P08A0 code, cleared it and drove with no problem, just noticed that the Hybrid Battery indicated on the dash that it dropped to 10% - 20% very quickly, especially if parked overnight or for a few days. But with driving returned to about 60 to 80% of its strength. Yesterday I had a Red Triangle on the dash and these OBDII codes: 1. P0A80 (Replace Hybrid Battery Pack), 2. P2505 (EMC Power Input Signal), 3. P0403 (EGR Circuit), and 4. P000A (Engine Position System Performance). My question is what is really wrong? It is difficult to believe I have gotten two bad replacement batteries back to back. I think there is something in the system that is slowly draining these batteries. I would expect them to reach 100% after a little driving at least when first installed. But with them dying after only a few months, something else must be wrong that has not been giving me a code, unless the key problem is reflected in the P2505 code. If there is a problem within the ECU, is there a likely part or parts that I could test and replace if bad without replacing the entire ECU? The car is in Florida with only 175,000 miles on it. It has been driven about 5,000 miles this year. Thank you.

good post thank you

Impressive instruction

Good to learn that this prius has a inverter AC.

感恩了解，謝謝分享！

thanks again...

You amazing teacher man thank you for you time and sharing this absolute valuable information I have Prius 2006 and I don’t know what to do shows on scanner poa94 code. Dc/dc converter performance What can i do man. Please thank you