2012 Intermittent DTCs when charge cable connected, car immobilized. BDU relay jct block?

4427 Views 13 Replies 4 Participants Last post by DrFumanchu350, Sep 23, 2020

russella

Discussion Starter · Jun 5, 2019

Symptoms
Plug car in:

Windshield dashboard light remains yellow. No chirp to indicate charging.
If open the door, DIC says "Not Able to Charge".
After 15m or so, I receive a text message from OnStar saying "Your 2012 Volt is not charging due to an interruption..."

After that, if I turn the car on:

DIC says :"Initializing Please Wait to Shift" for much longer than normal (10s?)
Then dashboard comes up with some abnormalities:
- Check Engine Light on
- Gas and Electric ranges are grayed out
Car is immobile...no traction power in any gear
If turn car off with foot on brake pedal, it power cycles instead of turning off
Codes set are P1EBD "Charge System Contacts Stuck Open", and P1E00 "HPCM2 req MIL illuminated"

In this above state, the car cannot be driven. Also the car won't attempt to charge. I have cleared codes with my OBDlink interface to restore driveability.

Playing with the car in the above state (clearing codes, setting them again with the cable, driving etc.) caused two other codes to show up: P0D22 "Battery Charger Output Current Performance", and P0AF8 "Hybrid Battery Pack Voltage Sense Circuit Correlation"

Other Notes
12V battery recently changed.
Symptoms have been reproduced on multiple charge cables (including 120V in 8A mode)
Dealer was unable to reproduce the issue so far. Will try to get it to misbehave for them next week.

I'm wondering if anyone has had symptoms like these? How were they addressed?

Thanks, russella

I don't see too many other complaints that seem to match my symptoms. I think what I'm seeing exactly matches what whiteelectric described in his thread from a few years back. Solution was to replace the relay-junction block/BDU:
https://gm-volt.com/forum/showthrea...pushed-dash-lights-work-Help!&highlight=p1ebd

fishhawk had a saga similar to this...he replaced his 12V battery which seemed to sort it out, but then didn't. From that thread it seems he finally had to get the BDU replaced to sort it out.

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DrFumanchu350

· #6 · Jun 5, 2020

Has anyone came up with a resolution to this yet? My intermittent issue is now a permanent one. Cannot charge at all.

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DrFumanchu350

· #8 · Jun 13, 2020

So, here is what I've done to date:

Updated software on BECM, HPCM2 and Charger to no avail
Replaced and reprogrammed on-board battery charger
Replaced Battery Charger Fuses
Checked continuity on all cables running from battery to HPCM2 and Charger

When I monitor in GDS, I plug in the charge cord and the voltage on the charger output immediately ramps up, but the battery never accepts a charge. I'm now left with changing the relay module inside the battery. I am going to have to basically tear down the battery pack to do this so I will inspect the charge contractor upon removal ad post updates. What really PISSES ME OFF is that this issue started intermittently around 70K and the car waited until 180K to completely not charge! Thanks Geriatric Motors!

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DrFumanchu350

· #9 · Sep 21, 2020

OK Got the definitive answer. Anyone with a Gen 1 with the dreaded intermittent P1EBD. Do NOT, Repeat, DO NOT let your car go out of warranty! This issue started intermittently when the vehicle was still under the powertrain warranty and they Reprogrammed, said it was software, etc. Here one year later No more charge and I finally got around to battery removal and discovered that the pin that controls the charge relay was loose and the poor connection generated excess heat. This all culminates into a very poor connection that goes bad. You think GM took any responsibility? HELLS NO!!!!

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DrFumanchu350

· #11 · Sep 22, 2020

russella said:
DrFumanchu- first of all, thank you so much for taking the time to reply to this with your results and conclusion. Also, double thanks for posting the image of the affected PCBA and the failed solder joint on pin R6. This is an excellent counter-hypothesis to what could be wrong with my MY2012 (though I initially suspected the contactor/relay itself was to blame)
Could you please provide more information on which module that is, and where it's located? I believe it is part of the BDU, and that it can only be accessed by dropping the battery, removing the top battery cover, draining the coolant, and disconnecting the BDU from the front of the battery...but I really hope you might say something different.

Thanks again,
russella

I believe GM calls it the "Battery Energy Control Module assembly" to be clear, the relays are fine, there are three 10 amp relays which control the heater, the APU and the Charger. The Pin that goes to the front plate has the issue. I bought the whole assembly from eBay for less than 100 bucks shipped. I put some dielectric in the connector to hopefully help it keep from arcing. But unfortunately you do have to remove the battery. That's why the Huge date range of my posts

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DrFumanchu350

· #13 · Sep 23, 2020

I know a tech who works at the dealership. I essentially paid labor and provided my own parts ($1500 savings) I'm around 1200 in labor. Upon further inspection, we also changed the circuit board that the relay module mates to as it showed signs of heat damage as well.

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DrFumanchu350

· #14 · Sep 23, 2020

One more caveat. It seems that 2014+ (I believe the breakpoint was somewhere in the 2013MY the part numbers changed

. This reinforces my belief that GM knew they had an issue and just silently changed the part. DIRTBAGS! If I had purchased a replacement part, they wouldn't have given me the better one. I would have gotten the F'd up 2012 Part!

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