On my 2014 Volt, 70k miles, I got the Service High Voltage Charging System error and Check Engine light. Another video suggested checking the Coolant Level in the tank THIS video refers to. Its a Two part tank with two reservoirs. The Left hand side of tank was less than 1/2 full, added 50/50 Dex Coolant from NAPA, then a friend used his obd2 device to CLEAR the codes. That totally fixed my Volt...it now charges up fully and no more Check Engine or Service High Voltage Charging System errors......for now!
Tip: use a small flat screwdriver wedge out the sensor. You'd push the flat end of the screwdriver in between the sensor (opposite side of that yellow dot) and the sensor slot wall to get it out. got mine out in 3 mins. Thanks for the video!
I’m glad to help. Although I only show what causes the code and how to change the sensor in this video. My other videos show how to clear the code. Just want to be clear.
Great Video...I have a 2015 Chevy Volt, in October 2020 I got the SHVCS error message, turned out that my coolant level was low, so I added Dex-Cool 50/50 coolant and cleared the error message with Actron CP9125 PocketScan Code Reader and presto like magic all was good to go...until today 8-1-23 I got the same SHVCS error message, however this time the coolant level was where is should be. Sounds like the same problem you talked about in your video. Would you recommend changing out the sensor?
Thanks for the tutorial, just replaced mine, now going to wait til the CEL comes back on then take it to a local indi shop that can reset permanent codes
For anyone wondering, to remove old sensor, it slides forward towards the Chevy logo Then I unplug the old sensor, insert the new sensor, that way I don’t accidentally drop the new sensor, took a minute or two to slide in place
We were driving our 2017 Volt in the desert yesterday (March 31, 2023 Southern California). The outside temperature was about 76. My husband was driving fast on an empty road. When we stopped and turned the car off, it turned off but the engine kept running. I checked the coolant temperature and it was 255 degrees. The car did this once before when I drove about 70 miles in the city on the freeway. I'm assuming it stays on to continue cooling the engine. I didn't notice a coolant message yesterday. After a brief stop, when I started driving, the outside temperature dropped to 60 degrees or less and the coolant temperature was 175. There is a way to see the coolant temperature on the dashboard while driving. My question is, at what point is the coolant temperature too hot even without a message and when should you pull over and let it cool off? I love this car. I didn't need to put gas in it for 5 months. I made it use gas because I figured it was getting too old. Sometimes the car will do that on its own. Thank you.
My 2015 volt had the same message pretty much on daily basis. I recently called around and found a dealer that simply did a software update, per GM bulletin 21-NA-224, and the problem is gone. I was lucky because the sales rep had the same car and was very helpful. I’ll update if the problem returns.
@@danwat1234 I was under the impression that there is a sensor which measures the resistivity of the fluid. As the fluid gets older , the resistivity gets lower.
The car is constantly measuring high voltage isolation in kOhms. It’s a very high number. But yes I believe that coolant health is a big factor in that number.
@@utjay2008 My understanding is if the high-voltage system is in perfect working order, i believe there should be no leakage of power no matter how conductive the fluid is. So having loss-of-isolation error code is from a combination of conductivity of fluid and power leakage, but not a dedicated sensor to detect dirty fluid. Also there may have been a software update than lessened the sensitivity to throw that code.
In my scanner I believe this is the "Hybrid/EV Battery Pack Coolant Level Switch". I just replaced my coolant level sensor and it is reading 3.55 V. Silly me I didn't think to get the before reading, but I had the "P1FFF-00 System Isolation / Coolant Level Sensor Fault - Hybrid/EV Battery Charging System Disabled" and "P1FFD-00 Hybrid/EV Battery Pack Coolant Level Sensor Circuit High Voltage" codes. 3.55 volts should be good.
Have the 12v battery tested first. But the wiring split is very near where I pointed in the video. That’s the problem area. Just follow that silver loom down another 6” or so.
Thanks for the video , I have a 2011 and I had this once and it did not allow me to start, added fluid , can’t remember if I used a tool or simply reset by pulling the 12 v battery cables, but if it happens again I have a better idea of the issue.
Replaced the sensor in the car? I don’t think I’ve made one. This video probably shows it pretty well though. I’d check around CZcams and see if any other videos pop up.
@Dimetri777 if your scanner can erase the code, but it comes right back, then it’s most likely the sensor or wiring, possibly the software. The VCX Nano is about $120, and the SPS2 / Techline Connect subscription is $40/2yr. The VCX Nano is the device that connects the SPS2/TLC software on your laptop to your car/OBD2 port.
@Dimetri777 here is the video I have on how to rewrite the HPCM2 software (same basic idea for the BECM software too). Using Techline Connect and a VCX Nano to fix Chevy Volt Service High Voltage Charging System Error czcams.com/video/eza-Y3oUnS4/video.html
@Dimetri777 that’s wild! Sounds like the sensor is definitely working. Very strange. Sorry I can’t help much more. If I think of anything I’ll post back. I guess it just needs a software update. If it’s a 2012 then check the wiring just behind the radiator. Keep us posted! Your comments will surely help someone else - which is why we’re all here!
I have a 2013 Volt. Looks like yours is older too. I went to order part number 22922224 but the site said it wouldn't fit a 2013 Volt but would work for model years beginning in 2014. Do you think that's right? Thanks again.
That’s really weird! Mines a 2012 and worked fine. I see a lot of the websites list it as 2014+. I’m not sure what I’d recommend. If it were me I’d buy it, but either way good luck!
Hi I've been trying to replace the sensor without having to pull out the whole tank. It seems in your video that it only comes out pulling towards you and the tank is attached on that side. So do I need to remove the tank in order to replace the sensor?
Hi, you can replace the sensor without removing the tank. You have to feel it, but you can slide it (forward or back - I can’t recall) after pushing the release.
I’ll take a look and reply later. I may make a follow up video to this one with a deeper look at voltages and ohms and some test stuff. I honestly didn’t expect many people to watch this one! Lol.
I’ve thought about this. I think the false positives from a magnet would be rare. I would BET that most failures are from sensor failures or wiring failures.
I just went through a $500 repair to have the tank replaced because of a bad sensor... 86 miles later getting the same High Voltage charging system error message... now they want 47200 for hybrid battery. Not sure I even trust the dealers diagnosis.
@@utjay2008 Im going to try and replace the sensor blind. Which way does it come out if I'm looking at the engine? Does it pull out away from the tank towards the engine or towards the grill??
My 2012 volt, 309k miles currently has had this code on for a year now, and I tried to diagnose it but the sensor is good and connector gets its 5v reference voltage, on top of all that I tried to get it reprogrammed and it's still not clearing the code anyone know what I should check next or what part of the system could cause this issue
Chevrolet dealer wanted $1100 to replace the entire reservoir. I replaced the $20 sensor and saved a bunch of money. Thank you for making this video.
Great to hear!
On my 2014 Volt, 70k miles, I got the Service High Voltage Charging System error and Check Engine light. Another video suggested checking the Coolant Level in the tank THIS video refers to. Its a Two part tank with two reservoirs. The Left hand side of tank was less than 1/2 full, added 50/50 Dex Coolant from NAPA, then a friend used his obd2 device to CLEAR the codes. That totally fixed my Volt...it now charges up fully and no more Check Engine or Service High Voltage Charging System errors......for now!
Has the issue returned?
Do you know or could you ask what OBD2 device your friend had used to clear the codes? you would be saving a lot of time and money for people.
Tip: use a small flat screwdriver wedge out the sensor. You'd push the flat end of the screwdriver in between the sensor (opposite side of that yellow dot) and the sensor slot wall to get it out. got mine out in 3 mins. Thanks for the video!
Just switched this out and it was super easy thanks to your video! Thanks!
Just changed the sensor. Not easy without watching this first. Great explanation. Thank You.
Awesome to hear! Thanks for watching and good luck with the Volt!
@@javierarellano2853 that’s the one! Good luck and thanks for watching! It available a lot of places, just search GM 22922224.
@@utjay2008 Good info! Thank you so much for part number and your video! Thanks fellow Volt owner!
Thank you so much for this video. I didn't know about the magnet and it fixed my problem after filling it. saved me a ton in dealer cost.
did the code have to be reset for your car to charge?
Just swapped mine out....working upside down, blind, and backwards became MUCH easier once I could see your example! THANKS!!!
Awesome to hear! Glad it helped!
Thank you for making this video. My 2013 Volt has that error code now. I am going to try this tomorrow on my car.
I’m glad to help. Although I only show what causes the code and how to change the sensor in this video. My other videos show how to clear the code. Just want to be clear.
Thanks. I’m trying this when I get home.
Thank you so much for making this video.
No problem! Thanks for watching!
Great Video...I have a 2015 Chevy Volt, in October 2020 I got the SHVCS error message, turned out that my coolant level was low, so I added Dex-Cool 50/50 coolant and cleared the error message with Actron CP9125 PocketScan Code Reader and presto like magic all was good to go...until today 8-1-23 I got the same SHVCS error message, however this time the coolant level was where is should be. Sounds like the same problem you talked about in your video. Would you recommend changing out the sensor?
Thanks for the tutorial, just replaced mine, now going to wait til the CEL comes back on then take it to a local indi shop that can reset permanent codes
For anyone wondering, to remove old sensor, it slides forward towards the Chevy logo
Then I unplug the old sensor, insert the new sensor, that way I don’t accidentally drop the new sensor, took a minute or two to slide in place
We were driving our 2017 Volt in the desert yesterday (March 31, 2023 Southern California). The outside temperature was about 76. My husband was driving fast on an empty road. When we stopped and turned the car off, it turned off but the engine kept running. I checked the coolant temperature and it was 255 degrees. The car did this once before when I drove about 70 miles in the city on the freeway. I'm assuming it stays on to continue cooling the engine. I didn't notice a coolant message yesterday. After a brief stop, when I started driving, the outside temperature dropped to 60 degrees or less and the coolant temperature was 175. There is a way to see the coolant temperature on the dashboard while driving. My question is, at what point is the coolant temperature too hot even without a message and when should you pull over and let it cool off? I love this car. I didn't need to put gas in it for 5 months. I made it use gas because I figured it was getting too old. Sometimes the car will do that on its own. Thank you.
My 2015 volt had the same message pretty much on daily basis. I recently called around and found a dealer that simply did a software update, per GM bulletin 21-NA-224, and the problem is gone. I was lucky because the sales rep had the same car and was very helpful. I’ll update if the problem returns.
Thanks for the info. Do you need to flush the battery coolant besides the software update?
@@Noitcetorp1234 there is no sensor that reads cleanliness of fluid in this car.
@@danwat1234 I was under the impression that there is a sensor which measures the resistivity of the fluid. As the fluid gets older , the resistivity gets lower.
The car is constantly measuring high voltage isolation in kOhms. It’s a very high number. But yes I believe that coolant health is a big factor in that number.
@@utjay2008 My understanding is if the high-voltage system is in perfect working order, i believe there should be no leakage of power no matter how conductive the fluid is. So having loss-of-isolation error code is from a combination of conductivity of fluid and power leakage, but not a dedicated sensor to detect dirty fluid. Also there may have been a software update than lessened the sensitivity to throw that code.
Do you think this could cause a p0c14 and 15 code?
Nice video
Thanks!
Thanks for the video. Would removing the float magnet also solve the problem? How long would it take to change the sensor?
In my scanner I believe this is the "Hybrid/EV Battery Pack Coolant Level Switch". I just replaced my coolant level sensor and it is reading 3.55 V. Silly me I didn't think to get the before reading, but I had the "P1FFF-00 System Isolation / Coolant Level Sensor Fault - Hybrid/EV Battery Charging System Disabled" and "P1FFD-00 Hybrid/EV Battery Pack Coolant Level Sensor Circuit High Voltage" codes. 3.55 volts should be good.
Good info! Thanks for sharing for the rest of us!
Might this solve P0128 Engine Coolant Temperature as well?
Great video! Now can you make one addressing code P1f58? Thanks!
Did you fix yours? My light is on. Gonna try swapping the valve.
Curious to know where the wiring was messed up for that connector? Replaced my sensor recently, but the code is still intermittently returning.
Have the 12v battery tested first. But the wiring split is very near where I pointed in the video. That’s the problem area. Just follow that silver loom down another 6” or so.
What fluid do I put in there. The left side one with the little lock on it
Use only dexcool premix (preferably from a dealer as it will be deionized).
Sometimes not always the case.. on Land rover the floater inside just stop floating.. but i guess gm is notorious just for the sensor
Супер видео!!! Все очень хорошо рассказано!
Thank you and thanks for watching!
Thanks for the video , I have a 2011 and I had this once and it did not allow me to start, added fluid , can’t remember if I used a tool or simply reset by pulling the 12 v battery cables, but if it happens again I have a better idea of the issue.
@@risknotdonot I put together a pair of videos of how to reset the error. It’s a latched code that needs reset within the HPCM2 module.
Can you post the video were you replaced that. I have the same exact light on my 2014 Chevy volt " SERVICE HIGH VOLTAGE CHARGING SYSTEM"
Replaced the sensor in the car? I don’t think I’ve made one. This video probably shows it pretty well though. I’d check around CZcams and see if any other videos pop up.
Thanks a lot for the video. Will the SVHC code clear itself when the problem is corrected? If not, will I need to get a scan tool that can do it?
To my knowledge you’ll need a tool. I use a VCX nano.
@Dimetri777 if your scanner can erase the code, but it comes right back, then it’s most likely the sensor or wiring, possibly the software.
The VCX Nano is about $120, and the SPS2 / Techline Connect subscription is $40/2yr. The VCX Nano is the device that connects the SPS2/TLC software on your laptop to your car/OBD2 port.
@Dimetri777 here is the video I have on how to rewrite the HPCM2 software (same basic idea for the BECM software too).
Using Techline Connect and a VCX Nano to fix Chevy Volt Service High Voltage Charging System Error
czcams.com/video/eza-Y3oUnS4/video.html
@Dimetri777 did you test the sensor with and without a magnet to switch resistance?
@Dimetri777 that’s wild! Sounds like the sensor is definitely working. Very strange. Sorry I can’t help much more. If I think of anything I’ll post back. I guess it just needs a software update. If it’s a 2012 then check the wiring just behind the radiator. Keep us posted! Your comments will surely help someone else - which is why we’re all here!
Hard to believe this part could actually fail. What did they make it out of, butter?
I think most of the failures are either wiring or software.
I have a 2013 Volt. Looks like yours is older too. I went to order part number 22922224 but the site said it wouldn't fit a 2013 Volt but would work for model years beginning in 2014. Do you think that's right? Thanks again.
That’s really weird! Mines a 2012 and worked fine. I see a lot of the websites list it as 2014+. I’m not sure what I’d recommend. If it were me I’d buy it, but either way good luck!
Make sense. Thanks a lot!
Hi I've been trying to replace the sensor without having to pull out the whole tank. It seems in your video that it only comes out pulling towards you and the tank is attached on that side. So do I need to remove the tank in order to replace the sensor?
Hi, you can replace the sensor without removing the tank. You have to feel it, but you can slide it (forward or back - I can’t recall) after pushing the release.
It slides toward the front of the car.
Where could I find what voltage the wiring should be at. I know you said you used to know the numbers.
I’m not sure the voltage ever really changes. I think it’s +12V on one side. I can’t recall where I even found the impedance ratings of the sensor.
I’ll take a look and reply later. I may make a follow up video to this one with a deeper look at voltages and ohms and some test stuff. I honestly didn’t expect many people to watch this one! Lol.
What are the flexible black plastic tubes coming from both sides of coolant reservoir? Mine somehow were chewed or ripped in half not sure how
The ones on the video I think are protective for shipping only. Emphasis on I think.
Not those…. the long tubes you keep moving out the way in video they plug in next to the black caps where you add coolant
Thank you for reply by the way
When you picked up the coolant reservoir to show inside it is hanging from top
Ah ok. Makes sense. I can’t go look at it right now. I think they are overflow tubes.
Chevrolet recommends that battery pack coolant level should be to bottom of black sticker.
Wonder what would happen if you left the sensor detached from the tank so the magnet could never interrupt.
I’ve thought about this. I think the false positives from a magnet would be rare. I would BET that most failures are from sensor failures or wiring failures.
There is also a defeat plug you can get that has a resistor to trick the computer into thinking the tank is full
I replace the sensor only and the engine light came back on same code
That you Brian? 😊
I just went through a $500 repair to have the tank replaced because of a bad sensor... 86 miles later getting the same High Voltage charging system error message... now they want 47200 for hybrid battery. Not sure I even trust the dealers diagnosis.
DONT TRUST THEM, THEY ARE DISHONEST OR DUMB
Is this the same for a 2014????
Sorry just saw this comment - I believe it is. The wiring is better though.
@@utjay2008 Im going to try and replace the sensor blind. Which way does it come out if I'm looking at the engine? Does it pull out away from the tank towards the engine or towards the grill??
@@drumcorpsfan going by memory and I could be wrong… but I think it pulls towards the grill.
Is it possible that the magnet could get stuck in the position of continuing that error? If so how could we fix that?
Anything’s possible, but I doubt that would happen. If it did, you just need a new tank. I think that would be the easiest sure fix for it.
@@utjay2008 one more thing. I haven’t tried to clear the HPCM2 code yet. How much do you assume(ballpark) that might cost me at the dealership?
@@Ashtonscreative anyones guess. I would say $200-400. They’re going to reprogram the module I’m guessing.
@@utjay2008 daammmiittt
@@Ashtonscreative I’ve got a few videos on how to clear the code or reprogram the HPCM2 module.
I replaced the sensor and the fluid level is normal. Now what?
If the SHVCS error is still present you’ll need to clear the code in the HPCM2 module. Or program it with the latest software.
Can just clear the code with a basic ELM327 dongle and a code clearer app such as Carista
My 2012 volt, 309k miles currently has had this code on for a year now, and I tried to diagnose it but the sensor is good and connector gets its 5v reference voltage, on top of all that I tried to get it reprogrammed and it's still not clearing the code anyone know what I should check next or what part of the system could cause this issue
Could be the float in the tank doesn't float any longer meaning the magnet is sitting on the bottom of the tank
You could try to remove the sensor from the tank, but leave it connected. Then clear the code. If the code comes back, it’s most likely a bad sensor.
A helpful video on YOOTUBE? Awesome I just got the sensor and was wondering how the faq to change it! Thanks!
Level sensor part number:
GM 22922224