Page 1 of 2 12 LastLast
Results 1 to 15 of 18

Thread: Not starting even with new battery and starter, seems to have lost TCM communication

  1. #1
    Registered Member


    Join Date
    Apr 2019
    Posts
    4

    Not starting even with new battery and starter, seems to have lost TCM communication

    The vehicle I have is a 2015 Mazda CX-5 with about 100k miles on it. It was running fine until the other before the following:

    I used the CX-5 to jump my Dodge ram truck which had a dead battery. I didn't drive the CX-5 then for a day or two and when I went to start it, it seemed the battery was dead, I think I needed to drive it around a bit after giving the jump.

    I then tried to use my truck to try jump starting the car but it wouldn't work.

    Since then I have replaced the battery and had a new starter put in by someone who came out to my house but it does not start.

    There is a code: U0101 which seems to have something to do with not being able to communicate with the TCM.

    The vehicle powers on fine as far as the dash, etc. I took the videos below to show what happens when I try to start it:

    video 1: When I get into the vehicle and touch the brake with the key fob inside the vehicle, the key light is solid green, which I think means it is successfully detecting the key fob: https://www.youtube.com/watch?v=E1X96vWV9gM

    video 2: This is a video of the dash when I am pushing the keyless start button with the key fob inside the vehicle: https://www.youtube.com/watch?v=QvKDft2MYbQ

    video 3: There is some kind of noise that happens during the same time as video #2, I put my camera under the vehicle to record it: https://www.youtube.com/watch?v=nJdz...ature=youtu.be

  2. #2
    2008.5 MGM MS3 rsvinylgraphics's Avatar
    Donated: $5


    Join Date
    Oct 2009
    Location
    Indiana
    Posts
    1,161
    is it possible you reversed polarity when you jump started the other vehicle

  3. #3
    Registered Member erhayes's Avatar
    Donated: $10

    Mazda CX-5 FWD Touring

    Join Date
    Jan 2007
    Location
    Cape Coral, FL.
    Posts
    2,823
    U0101 MAZDA - Lost Communication With Transmission Control Module 2 Comments | Add Comment Possible causes Faulty Transmission Control Module (TCM) TCM harness is open or shorted TCM circuit poor electrical connection

    Read more: https://www.autocodes.com/u0101_mazda.html

    I would first look at the fuses and then TCM connectors to see if you disconnected any of them. Ed

  4. #4
    ZOOOOOOOOOM ZOOOOOOOOOOOM mazdadude's Avatar

    '16.5 Mazda CX-5 Touring AWD, '05 PRIUS

    Join Date
    Dec 2005
    Location
    Red Bluff, CA
    Posts
    3,467
    Quote Originally Posted by rsvinylgraphics View Post
    is it possible you reversed polarity when you jump started the other vehicle
    Sure sounds like it...

    I would closely inspect each of the fusible links on the battery POS + terminal. And then the fuses in the engine bay.

    Hopefully you kept the old battery and starter, as they are not going to be the issue.
    Last edited by mazdadude; 04-14-2019 at 10:20 PM.
    Mazda's I have owned over the years. (boom07)
    80' Mazda GLC SPORT MT - sold
    81' Mazda 626 DX MT - sold
    81' Mazda 626 LX AT - sold
    82' Mazda 626 DX MT - sold
    82' Mazda 626 LX AT - sold
    85' Mazda 626 LX MT - sold
    87' Mazda 626 GT Turbo MT - sold
    85' Mazda RX-7 GSL-SE MT- sold
    87' Mazda RX-7 Turbo 2 MT - sold
    91' Mazda Protege LX MT - sold
    92' Mazda MX-5 Miata MT - sold
    93' Mazda MX-3 GS-V6 Special Edition MT - sold
    00' Mazda 626 LX-V6 MT - sold
    02.5' Mazda Protege5 MT - sold
    92' Mazda MX-5 Miata MT - sold
    06' Mazda 5 Touring AT - sold
    13' Mazda CX-5 Touring AT - sold
    14' Mazda 3i Grand Touring MT - sold
    15' Mazda CX-5 Touring AWD AT - sold
    03' Mazda Protege5 AT - sold
    16.5' Mazda CX-5 Touring AWD AT - current
    09' Mazda Mazdaspeed3 GT - current

  5. #5
    Registered Member 7eregrine's Avatar

    2016.5

    Join Date
    Jan 2017
    Location
    CLE
    Posts
    5,024
    I agreed it sounds like polarity EXCEPT, if I'm not mistaken, the car wouldn't have been able to jump the other car. So he would surely know he did that

  6. #6
    Registered Member Conrad 16.5's Avatar

    2016.5 CX-5 Grand Touring AWD titanium/black

    Join Date
    Sep 2016
    Location
    Northern Illinois
    Posts
    914
    Quote Originally Posted by 7eregrine View Post
    I agreed it sounds like polarity EXCEPT, if I'm not mistaken, the car wouldn't have been able to jump the other car. So he would surely know he did that
    Exactly right. If he had reversed polarity, not only would he have gotten a spark show but there's no way that his truck would have started in that condition.
    "Don't bother me with facts, Son. I've already made up my mind." -Foghorn Leghorn

  7. #7
    ZOOOOOOOOOM ZOOOOOOOOOOOM mazdadude's Avatar

    '16.5 Mazda CX-5 Touring AWD, '05 PRIUS

    Join Date
    Dec 2005
    Location
    Red Bluff, CA
    Posts
    3,467
    Quote Originally Posted by Conrad 16.5 View Post
    Exactly right. If he had reversed polarity, not only would he have gotten a spark show but there's no way that his truck would have started in that condition.
    Yes, but you are talking about jumpstart#1, I am thinking the polarity issue may have occurred on jumpstart#2, when he was using truck to jump cx5.

  8. #8
    2008.5 MGM MS3 rsvinylgraphics's Avatar
    Donated: $5


    Join Date
    Oct 2009
    Location
    Indiana
    Posts
    1,161
    Quote Originally Posted by 7eregrine View Post
    I agreed it sounds like polarity EXCEPT, if I'm not mistaken, the car wouldn't have been able to jump the other car. So he would surely know he did that
    If he/she made the mistake of hooking the cables up backwards on the first attempt to jump the other vehicle it could be the case or also if after attaching the clamps to the cx-5 battery, he/she then accidentally touched the other end of the jumper cable clamps together. Either of those would most likely fry the ECU or other electronics of the vehicle.

    It just seems like too much of a coincidence to have the issue right after the jump starting
    Last edited by rsvinylgraphics; 04-15-2019 at 11:20 AM.

  9. #9
    Registered Member


    Join Date
    Apr 2019
    Posts
    4
    Quote Originally Posted by rsvinylgraphics View Post
    If he/she made the mistake of hooking the cables up backwards on the first attempt to jump the other vehicle it could be the case or also if after attaching the clamps to the cx-5 battery, he/she then accidentally touched the other end of the jumper cable clamps together. Either of those would most likely fry the ECU or other electronics of the vehicle.

    It just seems like too much of a coincidence to have the issue right after the jump starting
    Now that I think about it, yes this did happen: "he/she then accidentally touched the other end of the jumper cable clamps together. ". I didn't think much of it at the time but now it makes sense. I should have been more careful I was in the middle of doing a bunch of repairs on my house when I went to do this so I was pretty exhausted and not being careful enough.

    So it seems, then, that it did fry the ECU or other electronics. Is the cost to replace these pretty significant?

  10. #10
    ZOOOOOOOOOM ZOOOOOOOOOOOM mazdadude's Avatar

    '16.5 Mazda CX-5 Touring AWD, '05 PRIUS

    Join Date
    Dec 2005
    Location
    Red Bluff, CA
    Posts
    3,467
    Quote Originally Posted by rickdsac View Post
    Now that I think about it, yes this did happen: "he/she then accidentally touched the other end of the jumper cable clamps together. ". I didn't think much of it at the time but now it makes sense. I should have been more careful I was in the middle of doing a bunch of repairs on my house when I went to do this so I was pretty exhausted and not being careful enough.

    So it seems, then, that it did fry the ECU or other electronics. Is the cost to replace these pretty significant?
    It should have blown one of the many fusible links that are located on the battery POSTIVE + Post, or a fuse in one of the fuse boxes, either under the hood or inside car. Have you inspected all of these?
    Sigs are visible only in your first post on a page. To change your thread display preferences, click here and enable 'Always Show Signature'.

  11. #11
    Registered Member


    Join Date
    Apr 2019
    Posts
    4
    I did inspect them and didn't find any blown out but maybe I missed one, I will check that again now, thanks.

  12. #12
    ZOOOOOOOOOM ZOOOOOOOOOOOM mazdadude's Avatar

    '16.5 Mazda CX-5 Touring AWD, '05 PRIUS

    Join Date
    Dec 2005
    Location
    Red Bluff, CA
    Posts
    3,467
    Quote Originally Posted by rickdsac View Post
    I did inspect them and didn't find any blown out but maybe I missed one, I will check that again now, thanks.
    Yes, check all carefully, I wish I knew the exact ones to tell you to check... There was a previous poster here NYC if I recall right, who also had an issue after a jump start accident, and it was either a fusible link or fuse...

  13. #13
    Registered Member concept's Avatar

    2014 Mazda3 S GT auto, 2008 MX5 6-speed

    Join Date
    Mar 2009
    Location
    San Diego
    Posts
    1,564
    Something similar happened to me (many years ago) when installing a battery that had the terminal posts reversed compared to the OEM battery posts. A very large fuse blew, preventing any further damage to engine electronics. Swapping the fuse was a piece of cake, thankfully.
    2014 3S GT, Deep Crystal Blue, Eibach Pro-Kit, Enkei PF01s, Koni Sports, Pirelli P ZERO ALL SEASON PLUS tires, 225/45/18
    2008 MX-5 Touring (Mazdaspeed CAI, HIDs, Progress/Koni Sports/Racing Beat sways, SST Magnaflow muffler and tips)

  14. #14
    Registered Member


    Join Date
    Apr 2019
    Posts
    4
    Thanks everyone, it was a fuse, I must have missed it when checking last night, it seems to start now. I will find out if the starter was actually bad too when I take it to the auto repair shop so they can test it.

  15. #15
    ZOOOOOOOOOM ZOOOOOOOOOOOM mazdadude's Avatar

    '16.5 Mazda CX-5 Touring AWD, '05 PRIUS

    Join Date
    Dec 2005
    Location
    Red Bluff, CA
    Posts
    3,467
    Quote Originally Posted by rickdsac View Post
    Thanks everyone, it was a fuse, I must have missed it when checking last night, it seems to start now. I will find out if the starter was actually bad too when I take it to the auto repair shop so they can test it.
    WOO HOO!

    For future reference, so we can help others, where was the blown fuse located.

Page 1 of 2 12 LastLast

Similar Threads

  1. Dead battery, alternator, starter?
    By 90210 in forum Mazda5 Lounge
    Replies: 6
    Last Post: 11-29-2017, 09:09 PM
  2. Starter or battery?
    By 90210 in forum Mazda5 Lounge
    Replies: 3
    Last Post: 04-03-2016, 10:37 AM
  3. Replies: 1
    Last Post: 12-05-2011, 12:42 PM
  4. battery/alternator/starter/wiring wtf?
    By kastleback in forum Protege5
    Replies: 2
    Last Post: 03-15-2010, 11:01 AM
  5. I really need this info! How long is the starter to battery cable?
    By Jason94Cobra in forum Mazdaspeed Protege
    Replies: 3
    Last Post: 04-18-2004, 09:39 PM

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •