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Discussion Starter #1 (Edited)
Hi all, just throwing this out there to share my recent scare with the dreaded "Propulsion power is reduced" message on 2017 Bolt. 28000 FLAWLESS miles, then one hot summer day (parked in garage, plugged into L2), I hit the remote start to pre-cool. 5mins later, turn ON to drive away and get the message (and service car symbol). Like I said, it had been PERFECT until then, so I was pretty startled. As I drove through my neighborhood it didn't seem weak, so I thought "maybe it was just a little hot from sitting in the garage, it'll probably go away once it cools off a little". But no, eventually I realized that power really was very much reduced and it wasn't really safe to drive. Parked it, then later that night (cooler temps), powered on and drove around just like normal - but the service car light still illuminated.

I used my OBD code reader and got a few codes, but little/no info anywhere. A few sounded like scary dead battery or main fuse problems. Anyway, the dealer took it in, "reprogrammed" something, and gave it back. It's been totally fine ever since (weeks of driving, all conditions and charge levels). I'll copy the service verbiage below, hopefully this helps someone in the future:

"Corrected by drive motor power inverter module reprogramming with SPS. Found DTC S P0AC4, P0AEE, P0BD2, P0BDC. Inspected and reprogrammed HPCM per TSB 18-NA-064 to correct. SPS code 17YN24133339."

Also wondering if anyone here can get their hands on that TSB, curious what it says...
 

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With all that verbage they use I'm pretty sure all they did was reset the code.
What kind of temps were you charging at?
 

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HPCM stands for hybrid ( or in the case of the Bolt more accurately high) power control module.

Issued 02/27/18



Hope this helps. Let us hope your problem is just the HPCM 2.

If you have Torque Pro, and Teleks PIDs, you can see the voltage of all 96 cells in the pack. It will be pretty obvious if you have a really low cell
 

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Discussion Starter #4
Hope this helps. Let us hope your problem is just the HPCM 2.

If you have Torque Pro, and Teleks PIDs, you can see the voltage of all 96 cells in the pack. It will be pretty obvious if you have a really low cell
That is helpful, thanks! I had been considering buying TorquePro (and bluetooth plug) to investigate my cell voltages... But I rarely get below 25% or even 50% charge so I don't know how obvious the problem will be yet, if there's a single cell dying somewhere in there...


I'm pretty sure all they did was reset the code.
What kind of temps were you charging at?
I'm not one to defend any dealership of taking credit (and/or money) for service they didn't provide, but in this case I'm sure they did reprogram the HPCM - either to mask a real problem, or to prevent false detects of a non-issue... The car had already been charged for many hours, but still plugged in sitting in a stuffy 115-120 degree garage, running the AC for a few minutes.
 

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I found the highest, and lowest cells in our pack. I put gauges for them on either side of the pack average cell voltage gauge. I have checked the voltage spread for those two cells at everything from 100% DIC charge to 1.6% DIC charge. The spread typically ranges from 0.012 volts to 0.025 volts. The spread at 1.6% was 0.110 volts. So that low cell was in the knee in the voltage curve. If you have a bad cell in your pack, I would expect to see that kind of spread at higher states of charge.
 

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I just had this happen today! Vehicle was charged and parked outside. It was going into conditioning mode (It was 95F outside) and plugged into L2. I didn't want to unplug while it was cooling the battery so I started the car while it was plugged in at which point the fan starting running very very loud. I heard the car give a series of beeps twice and when I got into the vehicle it said propulsion power reduced on the display. At first it seemed to drive normally but once I was driving for about 5 minutes I noticed that there was a significant delay when starting from stop. I also noticed a couple of instances where the regen didn't work or didn't work fully and I had to panic stop. I drove it about 30 miles and then parked it and pulled codes:

P0AEE
P0BD2
P0BDC
P0AC4

Cleared codes but I also received an email from OnStar stating that my Bolt has "An issue with the Engine and Transmission System " and to service it in 1 day. It has done some other random strange things in the past couple of months like not detecting the remote and refusing to charge. I noticed the TSB and I am really not looking forward to taking it into the dealer.

UPDATE: The issue has not returned. The vehicle is operating normally.
 

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I just had this happen today! Vehicle was charged and parked outside. It was going into conditioning mode (It was 95F outside) and plugged into L2. I didn't want to unplug while it was cooling the battery so I started the car while it was plugged in at which point the fan starting running very very loud. I heard the car give a series of beeps twice and when I got into the vehicle it said propulsion power reduced on the display. At first it seemed to drive normally but once I was driving for about 5 minutes I noticed that there was a significant delay when starting from stop. I also noticed a couple of instances where the regen didn't work or didn't work fully and I had to panic stop. I drove it about 30 miles and then parked it and pulled codes:

P0AEE
P0BD2
P0BDC
P0AC4

Cleared codes but I also received an email from OnStar stating that my Bolt has "An issue with the Engine and Transmission System " and to service it in 1 day. It has done some other random strange things in the past couple of months like not detecting the remote and refusing to charge. I noticed the TSB and I am really not looking forward to taking it into the dealer.

UPDATE: The issue has not returned. The vehicle is operating normally.
I'd check the health of your 12V aux battery...
 

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12v passes load test yesterday. I created a separate thread on the load test that I did. Read perfect all the way at the top of the green range and it dropped but remained in the green range under load for about 15 seconds. I went into the fuse panel for the first time and many of the fuses didn't seem to be seated all the way. Anyway I'm going to create a log and keep an eye on things.
 
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