DTC U2605
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Thread: DTC U2605

  1. #1
    Join Date
    Sep 2010
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    Long Beach, CA
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    Default DTC U2605

    So I got my first CEL yesterday As I was pulling out of the parking lot after work I realized the light was on, so promptly pulled back into the lot and called OnStar. I was given the code U2605, which means the "Battery Energy Control Module Lost Communication with Hybrid/EV Battery Interface Control Module 3." The first technical person I spoke with figured it was just some computer error and suggested that I try powering off the vehicle, waiting a minute, restarting, and then call OnStar back to see if the error code went into the history. I tried that, even going so far as to exit the vehicle while it was powered down for 2-3 minutes, but according to the OnStar folks I talked with the second time the DTC was still active. The funny thing was that when I called OnStar the second time, the level one guys suggested that I take it into the dealer within 5-7 days but the higher level tech guy said to take it in within 24 hours. This seemed a little extreme to me since the car appeared to be working fine otherwise, and the first tech guy I talked with seemed to suggest it would probably go away after 3 trip cycles.

    Since the car was working I went ahead and drove home (30 all-EV miles) and arrived without incident, plugging in to charge right away. After a couple of hours I needed to move my car out of the garage even though I didn't have a full charge, so I unplugged, powered on, and moved the car only to find the CEL was still lit. In the morning I went to check out my car and lo and behold the CEL was out. Just as the first tech suggested, three cycles and it went out. We'll see if it comes back, but it appears to have been a non-issue in my case. I should be going in to the dealer in the next week or so for the battery enhancement, so if it happens again I can always alert my dealer at that time.

    Since I wasn't able to find too much help on my error code (or the related ones U2603, U2604) on this site I figured I would go ahead and report my non-event here just in case this happens to anyone else.
    2011 #130: 31,050 EV miles / 35,746 total miles (turned in 12/21/13)

  2. #2

    Default

    @ LeelaLB,

    Sorry to hear this. Let us know when you go to the dealer for your battery enhancement. I would still bring up the codes to them even if this issue does not come back.
    If you have any further questions feel free to contact the
    Chevrolet Volt & Spark EV Advisor Team:
    (877) 486-5846
    Chevrolet Volt & Spark EV Advisor Hours:
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    Saturday 11AM to 8PM EST.
    Closed on Sunday.

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  3. #3
    Join Date
    Jul 2009
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    Colorado Springs, Colorado
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    3,141

    Default

    This thread has a manual with most error codes..
    http://gm-volt.com/forum/showthread....codes)-Mode-06

    Those messages are on p 658. Says MIL should only last 1 cycle -- so if it persists it means the comms problem persists.
    ________________________________
    BoultVolt Red 2011 #3745. More freedom than electric.
    Personal best, 82.1 miles on one charge.

    While I'm moderator my job there is to delete spam. To be clear, in my posts I'm speaking as myself. These views are my own and don't represent this board, my university, employer,etc.

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  5. #4
    Join Date
    Sep 2010
    Location
    Long Beach, CA
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    166

    Unhappy U2605 Returns

    Unfortunately it looks like the first incident of U2605 was indicative of an actual problem. Yesterday after I got to work and plugged in my car for the day, I got a charge interrupted message. When I went down to investigate I found that the EVSE seemed to be working but the light on the dash was out. I unplugged and replugged only to have the orange light on the dash stay orange. So, I unplugged and started the car only to get a CEL, a reduced propulsion message, and have the engine kick on even though I still had about 8% of my battery charge remaining. I cycled the car on and off a couple of more times and was able to get the car to start charging at least, so I left it for a couple of hours since I didn't want to deal with having to get the car to the dealership (30 miles away) at that time in the morning (before 8 AM...in Los Angeles...with loads of rush hour traffic).

    By 11AM the car was still charging and when I unplugged the reduced propulsion message was gone and I was able to drive the car (yeah!). So, I called OnStar and confirmed that the CEL was due to a re-occurrence of U2605. I elected to have OnStar contact my dealership and let them know that I was coming in while the car was still operational. Of course, when I got to the dealer (exactly when I told OnStar I would be arriving there) they seemed to have no idea of why I was there. :sigh: Even less inspiring was the fact that the first person in the service department that I talked with had absolutely no interest in helping me and passed me off to someone who was AT LUNCH at the time. :double sigh: When the guy who was at lunch called me at home, he said that he was going to be out the next day and wondered why I was passed to him. When I told him what happened, he pretty much said, "yeah, that's what I thought." Meanwhile I'm thinking, "Great, the only responsible person at this dealership who isn't afraid of the Volt is going to be off tomorrow." Anyway, after explaining the trouble with the car I also asked on the status of the parts for the customer service enhancement that had supposedly been ordered by the dealership almost 4 weeks ago. He said he'd look into it and have the person who would be handling my case get back with me.

    An hour later I get a call from a third guy at the dealership who says "Great news, your parts for the recall are in, and when we do that it should take care of your CEL too!" WTF!?!?! How does a couple of brackets, some glue, and a coolant sensor have anything to do with a BCM failure?? At this point I'm thinking that this is exactly why people HATE going to the dealership for service, or at least what passes for service at dealerships. But whatever, I tell the guy that I'm pretty darned sure that the "recall" won't help the CEL, but that first things first I'll need a rental car so that I can get to work the next day. I tell the guy when I'll be in and he says he'll get things together.

    When I go to get the rental the guy has done nothing. So, while I'm waiting around I ask him when the parts for my "recall" came in, since they were ordered a month earlier. He then proceeds to tell me that the reason I need a new charger is because the old one wasn't built very good. :triple sigh: That's not what I asked, so I ask again and he pretty much blows me off. Before the rental car guys come he then says that he'll get back to me next week when the recall is finished, probably Wednesday or Thursday (i.e., a full WEEK after I brought the car in). At this point I'm trying really hard not to flip out and firmly say, "No, you will be calling me as soon as you have any information as to what is gong on with that CEL." He says he will, but I don't believe that any more than I believe that the battery enhancement will fix my BCM problem.

    One hour later I'm on the road in my SUV rental (the smallest GM car they had) with an empty gas tank (grrr) and thoroughly dejected. Before you all say to call the Volt Advisors, I called the VA line first thing this morning with my tale of woe. The person I talked with was great and contacted my service advisor to let him know the importance of keeping me in the loop. He also stressed the importance of keeping the Volt techs in the loop, which puts me at ease that they will at least try and figure out the cause of the battery problems and not just put the brackets on and call it a day. We shall see.
    Last edited by LeelaLB; 05-04-2012 at 05:03 PM.
    2011 #130: 31,050 EV miles / 35,746 total miles (turned in 12/21/13)

  6. #5
    Join Date
    May 2011
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    Delaware
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    Default

    Call the Volt Advisor. Seriously, though, they've helped a lot of people here. Hopefully the one you talked to this morning will be able to help you out.

    From what I've read, I believe your error code is either a loose connection or a bad board. The Volt's battery is made up of four modules - in layman's terms the error code you got is that the master battery computer can't get the computer in charge of module 3 to pick up the phone. That could be because of a loose connection (phone line is dead,) or because there's something wrong in Battery Interface Control Module 3.

    I'm not a Volt tech, but I'd imagine the first step in diagnosing such a problem is to open up the battery pack - which requires removing it as they are doing for the recall. The recall itself shouldn't have any impact on your CEL, but it makes a very convenient time to fix the pack if it's simple, or to replace it with a new pack if it isn't - that's probably what they were trying to say.
    Walter
    C4884 - White Diamond, purchased 10/15/11

    Volt FAQ

  7. #6
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    Sep 2010
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    Long Beach, CA
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    Default

    Quote Originally Posted by saghost View Post
    that's probably what they were trying to say.
    You may be right about what it takes to diagnose the issue, but I truly think you are giving this service advisor waaaaaay too much credit. I might be inclined to believe that he just misspoke if I hadn't talked with this guy about other things. Unfortunately, he really is clueless and I will never allow him to be my service rep at this dealership again.

    I'll be sure to provide an update as to what the service techs find...assuming I can wrestle that information out of my service advisor.
    2011 #130: 31,050 EV miles / 35,746 total miles (turned in 12/21/13)

  8. #7
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    Sep 2010
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    Default Update

    After spending the last few days going back and forth with the dealer explaining exactly what happened when I got the CEL (e.g., me reassuring them that I was not going up any hills when I got the CEL and reduced propulsion message but rather was parked) I get the sense that they can't really pinpoint the cause. Instead it sounds like they're just going to start replacing stuff. Today they ordered replacements for all four control modules and two relays. They'll have to put those in and do the battery enhancement as well, so it will be a few more days at least with the SUV.

    On the plus side I'm leaving for vacation to the Mayan Riviera on Monday, so even if I don't have the car back by the end of the week I won't care
    2011 #130: 31,050 EV miles / 35,746 total miles (turned in 12/21/13)

  9. #8

    Default

    @ LeelaLB,

    We will definitely keep an eye on this and we will do all we can get you out of the SUV and back into your Volt as soon as possible. If any new information comes in before you leave we will be sure to get it over to you.

    Enjoy your trip!
    If you have any further questions feel free to contact the
    Chevrolet Volt & Spark EV Advisor Team:
    (877) 486-5846
    Chevrolet Volt & Spark EV Advisor Hours:
    Monday - Friday 8AM to 9PM EST.
    Saturday 11AM to 8PM EST.
    Closed on Sunday.

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  10. #9
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    Sep 2010
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    Default

    Quote Originally Posted by Chevrolet Customer Svc View Post
    @ LeelaLB,

    We will definitely keep an eye on this and we will do all we can get you out of the SUV and back into your Volt as soon as possible. If any new information comes in before you leave we will be sure to get it over to you.

    Enjoy your trip!
    Thanks Trevor! Any additional info or help in expediting things that the VA's can provide is always appreciated. I do understand how difficult it can be to try and diagnose something that is an intermittent problem, and know that the tech folks at GM are doing what they can to figure this out. In the mean time, I just keep dreaming of the beach and my toes in the sand. Can't wait to get unplugged
    2011 #130: 31,050 EV miles / 35,746 total miles (turned in 12/21/13)

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  12. #10
    Join Date
    Sep 2010
    Location
    Long Beach, CA
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    166

    Default And we're back

    Just a quick note to update all on what happened with my Volt. Before leaving on my trip I told my service advisor at the dealership to keep me updated via email on the progress of work on my car. Finally at 6PM on Wednesday (5/16) I got the following message:
    glad to let you know that veh is back to original designed running condition.with gm ingenering dept.parts that gm order for your veh where installed and took care of your veh concern.today.we test drove veh for about 30miles and is working as designed smooth as can be.we are charging batterys and will rediagnose system.but is fine.thank for being so patient and understanding.we appresiate that.xxxxx xxxxx harbor chevrolet.thanks.
    I really wish I altered that message, but that's what I got (I X-ed out his name). On the one hand, I'm happy he at least contacted me, but it also makes me sad that this is the kind of person who the dealership has communicating with their customers. After laughing and shaking my head, I responded that I would pick the car up on Monday (5/21) unless they found something else wrong.

    Today before going in I called to talk to the service advisor to remind him that, per the customer satisfaction program/battery "recall" my vehicle was to be fully charged and gassed up. He said it would be and that they were going to wash it again too. Great.

    When I arrived at the service counter they gave me the paperwork that outlined what was done to solve the DTC U2605 issue:

    "Replace the drive motor battery wire junction block relay, battery energy control module, and the four hybrid/EV batter interface control modules inside the drive motor battery."

    After signing off on that and the service campaigns I got my keys and went to my car. Not surprisingly my gas tank was showing a whopping 1 gallon of gas (I brought it in with 2 gallons), but at least it was mostly charged, even if they only charged it the week before to prove that the control module issue was solved. Oh well, I've given up fighting these fools. At least I finally have my car back and since I was out of town for one of the weeks when my car was in the shop I only ended up putting $50 worth of gas in my loaner SUV. Here's hoping my car stays out of the shop, and if it does have to go in for something, you can be sure I'll never work with this particular service advisor again.
    Last edited by LeelaLB; 05-29-2012 at 04:11 PM. Reason: clarification
    2011 #130: 31,050 EV miles / 35,746 total miles (turned in 12/21/13)

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