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Did someone notice that after the 2 modules software update the estiated time for fully charge is (in my case) 8hr and 15min, instead of 8.45 - 9hr that is used to, that is why I supose my car can only use 9kwh or 0.9kwh/1 bar of range.
 

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Is this also normal after BECM and HPCM2 reprogramm? I lose every energy bar at 0.8kwh used, so on 4.2kwh used my battery is already half instead of ~60% as it used to - see in the image below.
171035
 

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I still managed to get 80km with 9.3kwh used on a test at 80km/h on highway. Before HPCM2 update, I can get this range with 10.2kwh. The technician from Opel told me that the range is not that affected after update, instead, the method of calculation on kwh is changed....I don't know, maybe is right....
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Looks to still be there.

View attachment 171011
Hi,

I finally figured it out. I needed to be in the USA to get it to work. A VPN connection later and the subscription was suddenly available.
Reprogrammed the module but the error comes back after a full discharge unfortunately. I'll try the BECM K16 reprogram next.

I have the defeat module as well - did not help.

Mats
 

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I had the “Service High Voltage Charging System” DIC message along with the check engine light last week. I just got it back from the dealer. I was prepared for it to be the bad battery coolant level sensor described in the old TSB PI0961. The service advisor told me that TSB does not exist anymore.

The codes it was throwing were P0AA6 and P1FFF. The paperwork says “Reprogram the HPCM2 and the BECM as per PI5920J”. I had left a copy of that TSB (PI5920J) along with the old one mentioned above on the passenger seat to help get them started in the right direction, lol.

Service was covered under the 8 year/100,000 mile VOLTEC warranty. I’ll be sad when that expires this spring.
 

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Hi - newest member with this problem. I think I've read every page and still have some questions.

Dealership reprogrammed after finding P1FFF and P0AA6 2 weeks ago. I don't know if they did hpcm2 and the BECM, but will find out today. SHVCS came back, and they now want $993 to replace the sensor of course. I'm handy with cars, but I'm no technician, so I have a few choices: 1) thinking about using a defeat plug, and then either buying a vcx nano to clear the SHVCS error or having my local shop do it for me, 2) trying to replace the sensor myself without replacing the coolant tank, and reprogram.

1) Does anyone have the part number for the sensor, and is there a walkthrough to replace?

2) Is the VCX easy enough to use? If so I'd much rather do this than go to the dealer every time, but has anyone posted instructions on doing this software update?

3) Since I already have the error, are these even my best options?

I've read a few accounts from members going through these steps and still being stumped, or having the defeat in place and the code coming back. I just want to take the most logical steps if someone can advise.

Thank you!
 

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Edit: Nvm WOT, I found an official document by accident, stating that the 5 V are indeed correct for the HPCM2 and my 3.563 V look like serious trouble
I have ~3.2v coming through my sensor harness, even after removing the pigtail to inspect the splice. If this is the only problem, I'm thinking I will use a 16k resistor to bring the current down to the acceptable volage range for the HPCM2 to read. This calculation is based on the 24.7k resistor values used by the defeat plugs to correct the sensor issue when running at 5v.
 

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My turn.
I got the message the day I got back from a long vacation drive. 2014 with just over 100k miles. P0AA6 & P1FFF with no charge. M-M charges pack and all other functions are fine. Pack cell balance is within 10mv across all cells. I installed the 24k ohm bypass plug when I first got the car after reading all of the problems folks were having with the battery tank sensor going bad. Since the codes had already locked I pulled the bypass plug and measured 5v logic to the control module. The coolants have never dropped at all while I have had the car. The fact that the codes fired even with the bypass plug...I am concerned something else is causing a HV isolation that fired the hard lock code. VCX Nano shows 400k ohms isolation reading which is way below the 3000k (3 meg-ohm) the TBS calls for. I would expect the lookup table drops the hard lock at some value...which mine might have.

Since the coolants have never been changed (and I am familiar with water cooled high power transmitters from a past life) I did a resistivity test of coolant extracted from the tank of the car and compared it to new coolant. I have a Qt Ball jar colloidal silver generator I set up with high purity silver strips so I used that for the test. I connected 20vdc to the jar with an HP 410C connected to measure the leakage current. The test sample from the car measured 12ma after letting it settle for 10 minutes. The new coolant measured .35ma after the same time period. That shows that the old coolant in the car is rather leaky.

My question for those in the know is whether I can substitution-replace the coolant over a couple of weeks of long driving (I don't have a vac-fill) and get the reading back into the range of where a re-flash of the module will fix the problem or whether something else is possibly causing the leakage measurement to be so low in value?

I had planned on taking it to the dealer for flushes...this beat me to it. In the mean time I don't think there are any problems driving the car as-is like Erick did with old Sparkie.
 

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Damn Voltreg...thats good info. I'm having the same codes/issue on MY2012 @130K miles Volt for the second time after reprogramming the HPCM2 about 1.5 years ago. I'm likely going the Flash the HPCM2 again since my $40 2 year acdelcotds subscription is still active. I've been having some trouble getting my VCX nano to work with GDS2 tho...figuring out that issue currently.

I also purchased a second acdelcotds $40 2 year subscription and flashed my sisters MY2014 volt with 170k Miles about a year ago after experiencing this issue and hers has been fine since. Interestingly both times it happened was after charging in ambient temps of 85+ degrees on at 240v

Seems the HPCM2 reflash will likely be the best/most permanent solution as it changes isolation values that set a P0AA6. I think should be higher than 275kohm as in TSB PIC5920j: "Important: If you have any moisture that is found in the battery during the drain plug inspection or the Isolation test resistance will not go above 275 kOhms after the HPCM2 and the BECM have been updated, please contact the Technical Assistance Center (TAC) for further direction." https://static.nhtsa.gov/odi/tsbs/2019/MC-10163668-9999.pdf
 

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I suspected coolant degradation at first, but my mechanic said it was unlikely. That’s when we hunted down the faulty wire harness for the coolant level sensor.
interestingly, the sensor showed it was getting 5v constant on the multimeter, so it must have been intermittently failing while driving.
$10 replacement wire fixed it.
 

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Ok...I did another battery coolant sample test with the jar and it came out 2ma which is a 6 fold drop from the original reading. I don't know how the coolant loop works as to whether coolant replaced in the tank actually gets mixed in quickly with the rest of the coolant in the loop as the pump runs or it mostly sits there and very slowly gets diffused into the rest of the coolant.

I re-flashed the the control module 2 and since the car never had the battery flash recall done I did that also. The car charges again and the isolation reading is at 3000k. I plan on driving the car for a month as-is (if it keeps charging) and checking the coolant again. At that point I may either take it to the dealer and have the loops flushed or buy my own vac-fill setup. Having always done the vast majority of auto service on my autos I would hate to stop now.
 

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Ok...I did another battery coolant sample test with the jar and it came out 2ma which is a 6 fold drop from the original reading. I don't know how the coolant loop works as to whether coolant replaced in the tank actually gets mixed in quickly with the rest of the coolant in the loop as the pump runs or it mostly sits there and very slowly gets diffused into the rest of the coolant.

I re-flashed the the control module 2 and since the car never had the battery flash recall done I did that also. The car charges again and the isolation reading is at 3000k. I plan on driving the car for a month as-is (if it keeps charging) and checking the coolant again. At that point I may either take it to the dealer and have the loops flushed or buy my own vac-fill setup. Having always done the vast majority of auto service on my autos I would hate to stop now.
So you went from 400k to 3000k resistance after what sounds like you only replaced the tank (resevoir?) coolant?
 

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MY2012 130k Miles in Los Angeles 50-80 degree (general) operating temps. Car has been sitting for a few months with a full battery and connected to the EVSE. I'm experiencing a P0AA6 that wont go away even with a HPCM2 reprogram. From what I've read the Isolation resistance needs to be above 400K ohms to clear the code while anything below 325k sets the code...according to GDS2 through my VCX Nano mine is at 225K ohms. I did use non GM Prestone dexcool mixed with distilled water when I should have used de-ionized water 3 years ago when I did a battery coolant replacement. Based on what Voltreg is saying I'm now wondering if that may be related.

I guess I'm wondering if anyone has had isolation resistance stay too low and what they or their mechanic/tech ended up doing that fixed it.
 

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I swapped the tank coolant and re-flashed and all is well so far with 2 charges so far. The Gen 1 Volt has over a million lines of code. Maybe they really loosened up the set point in the firmware update or maybe I got lucky.

As in Geo-politics we only see the shadows on the wall and the results after the fact...often with dubious explanation. Hopefully someone in the know will provide detailed info on the code. I would suspect NDAs and other agreements are in effect so one should not hold their breath on that. Hats off to Jack and Collin at EVTV for cracking the Tesla drive-train code for their transplant and solar builds. Maybe someone will try the Volt with the CANDue. I'm hardware...not software.
 

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Hi! I have problem with isolation resistance.
I replaced the battery heater because it was damaged. For 4 months the car was disconnected from the 12V and HV battery. After installing the heater and battery, GDS2 shows 0kohm resistances and errors P1AE6, P1FFF.
The car had software updated a year ago. The battery resistance was measured with a special device and it is OK. What should I check?
 
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