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Yesterday unplugged the leased 2016 and got in as I've done countless times over the past 6-7 mos. Pressed power everything seemed normal. Waited for the screen to change and shifted into Reverse. DING! Message "Action Required - Shift to Park". And, the check engine light on.
So I shifted and "Information - Battery Saver Active".
Same thing a couple of cycles.
Drive, Reverse, etc. won't engage.

Call into Onstar who tells me the following codes are active:
P1E00 - Elec system not working HPCM....
U2619, U2620, U2621, U2622, U2623, U2624 - all: Lith battery not performing issue with charge pack...

Tow to dealer, "huh, that's a new one. here's a loaner and we'll check it out."

Call from dealer today, "well the onsite Volt expert has never seen this. The factory is going to send out an expert, so keep the loaner and we'll let you know."

Good news, free loaner. Bad news, no HOV stickers <grumble>, for who knows how long.

Thoughts anyone?
 

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Yes please let us know what you learn. I don't remember ever seeing codes that start with a "U". Maybe WOT can offer some guidance.
 

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There are a few other "Shift to Park" threads here on the gen 2. Good luck.
No
Based on all the U-codes and "Battery Saver Active" message this ones just a dead 12V , NOT likely related to the Power Inverter Module issue from the other thread.
You typically need to be moving for that. (not dead after supposedly charging)
The dealer will get this one sorted pretty easily I figure.
WOT
 

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Hopefully they will. The fact that they need to bring in a factory tech doesn't give me much confidence.
 

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Discussion Starter #8
F7C885F2-11C4-4391-9CDB-3DDA4F1C1193.jpg 85170BD0-6913-4B27-BBFF-39186F0175D2.jpg Well folks, a little over a week and a half later and I finally got my Volt back. Here's the gist of the issue:
They had to replace the Battery Energy Control Module which died. Why? Who knows. But, it took a factory rep to figure it out.
Attached are all the issues they found including a lot of recalls. Heads up if you have a 2016 might want to take a look at many of these required recalls.
Also, thankfully they gave me a loaner car which as it was a brand new 2017 had the latest firmware for everything. This proved to me that the Carplay issues I had experienced were fixed as the 2017 had zero radio/Carplay crashes over the 1.5 weeks plus.
What a pain in the rear it's been but at least the dealer was cool and gave me a free loaner.
Happy to have my HOV lane stickers back thought!
 

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Yes please let us know what you learn. I don't remember ever seeing codes that start with a "U". Maybe WOT can offer some guidance.
Under OBD2 standards, a U-prefixed DTC is strictly used to identify vehicle network communications codes/issues.
In the case of these particular U-codes, some of the major differences between the BMS used in the Gen1 and Gen2 are exposed.

In the Gen1 there was a Battery Energy Control Module (BECM) mounted inside the battery assembly (just behind the relay/junction block) that communicated with 4 Battery Interface Control Modules (BICMs) mounted on top of the 3 major battery sections. The BICMs physically connected to each cell group to monitor voltages, perform cell-balancing, as well as to monitor a number of temperature sensors. (9 or 13 depending on the year) This BMS data was communicated to the BECM via a dedicated hard-wired network channel with all 4 BICMs and the BECM then forwarded that data as required onto the applicable GM-LAN network members (but mostly HPCM2)

On the Gen2 these 4 physical BICMs have been completely eliminated. There are now 12 BICMs however they are now integrated within the BECM itself and essentially creating 12 BMS communication channels for voltage, temperature, and current measurement/monitoring. This new BECM is now mounted on top of the battery pack section 1, just forward of the manual service disconnect.

In the OPs scenario these particular BICM U-codes (U2603, U2604, U2605, U2606, U2617, U2618, U2619, U2620, U2621, U2622, U2623, and U2624) indicate the BECM was for at least a time unable to communicate with some or all of the BICM hardware. Often these types of communications issues can be set falsely when a 12V problem exists as all of the cars various networks still rely on the 12V system to provide the source voltages for these communications. However if the DTCs persist (with no 12V issue present) it might indicate a network wiring or hardware issue. Since there no longer is ANY wiring between the BICM channels and the BECM it appears the problem was traced to being an issue with the BECM itself and it was replaced. I'm pretty sure the first of this type of fault we've experienced here. Hopefully it remains a rare thing. It may have even been replaced simply as a precaution or for failure analysis.

One other thing I'll mention here is the "Shift to Park" message in the DIC is something the Gen2 cars will routinely do when almost ANY critical error occurs. So there can be no relationship formed with THAT particular message to any one singular fault as some are trying to allude in this and other threads. (and there is no F-module! lol)

HTH
WopOnTour
 

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Mine has been at the dealer now for 12 days for "Shift to Park" while driving. When I called on it the only thing they could tell me is that they replaced the 12v battery and it didn't fix anything. Uh huh.

I'll post details if I ever get any. Meanwhile I'm driving their bloated loaner 100 miles/day. We'll both be unimpressed when I get my new car back.
 

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Mine has been at the dealer now for 12 days for "Shift to Park" while driving. When I called on it the only thing they could tell me is that they replaced the 12v battery and it didn't fix anything. Uh huh.

I'll post details if I ever get any. Meanwhile I'm driving their bloated loaner 100 miles/day. We'll both be unimpressed when I get my new car back.
Two others have reported similar experiences...Seems that some service dept immediately reach out to Volt experts while others seem unwilling...The way to look at it is while it's not ideal, look at the postives, everyday you don't have the Volt is 100 miles saved...
 

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Not sure about the codes, but I had the same thing happen to me with the Battery Saver Active. It came to a point where I had to jump start the car every time I wanted to drive it. Dealership replaced the 12v battery and everything is fine so far.
 

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Not sure about the codes, but I had the same thing happen to me with the Battery Saver Active. It came to a point where I had to jump start the car every time I wanted to drive it. Dealership replaced the 12v battery and everything is fine so far.
Most commonly the "Battery Saver Active" message will only appear when someone is powering up the car in "service mode" (powering up the car by holding the POWER button for 5-6 seconds with foot off brake) without a suitable trickle charger installed on the 12V battery. This is because service mode does not engage the 12V charging system and as such it will run down the 12V battery in a matter of 20-30 minutes depending on what's powered on. So this occurs most often in the shop or with someone mistakenly using service mode to listen to the radio.
The message WILL NOT normally appear with the car ON at any time , unless there is a serious issue with the 12V charging system (DC-DC converter or cabling) or the battery itself has a shorted cell. (possibly what they found on yours)
Hopefully you are now good to go
WOT
 
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