Chevy Bolt EV Forum banner

1 - 5 of 5 Posts

·
Registered
Joined
·
3 Posts
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...
 

·
Registered
Joined
·
3 Posts
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?
 

·
Registered
Joined
·
3,576 Posts
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
 

·
Registered
Joined
·
3 Posts
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.
 

·
Registered
Joined
·
3,576 Posts
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.
 
1 - 5 of 5 Posts
Top