GM BCMs, Instrument clusters and milage

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  • greasybob
    Senior Member
    • May 2008
    • 1590

    GM BCMs, Instrument clusters and milage

    I recently repaired an 05 saturn Ion that was struck by lightning. This included replacing a lot of electronics and almost every module on the vehicle. I used all used modules and was able to get eveything programmed and flashed to work together. Everything works like it should with the exception of the odometer. I did not replace the instrument cluster as the gages and lights still all work, I did however replace the BCM which is where I believe the milage is stored. The Odometer still reads the proper milage but when driving the vehicle the odometer does not change. I have the instrument cluster from the doner vehicle where I got the BCM. When I plug that one in the odometer does work, but of course the mi8lage is wrong. Did I miss something when setting up the used BCM ? Is there any way to get the used BCM and cluster to work together ? Will a new BCM allow me to set up the proper milage ?
  • Rich Barton
    Senior Member
    • Sep 2007
    • 452

    #2
    Originally posted by greasybob
    I recently repaired an 05 saturn Ion that was struck by lightning. This included replacing a lot of electronics and almost every module on the vehicle. I used all used modules and was able to get eveything programmed and flashed to work together. Everything works like it should with the exception of the odometer. I did not replace the instrument cluster as the gages and lights still all work, I did however replace the BCM which is where I believe the milage is stored. The Odometer still reads the proper milage but when driving the vehicle the odometer does not change. I have the instrument cluster from the doner vehicle where I got the BCM. When I plug that one in the odometer does work, but of course the mi8lage is wrong. Did I miss something when setting up the used BCM ? Is there any way to get the used BCM and cluster to work together ? Will a new BCM allow me to set up the proper milage ?
    Hi Bob,
    you need a new bcm and set up with tisweb, then it will have you write the mielage then do security and your done,check tsb first there is some out on set up threw tis web.
    Rich Barton
    C.R.B. Repair

    Comment

    • greasybob
      Senior Member
      • May 2008
      • 1590

      #3
      Thanks for the reply. Here is some information you might find helpful if installing a used instrument cluster into an ION. I tried the reflash of the BCM again except this time I had the instrument cluster unplugged during the reflash. When the flash was done I cycled the key and then plugged the cluster back in. Now my cluster that had the correct mileage on it shows the mileage that is in the used BCM. If nothing else now you know how to install a used cluster into an Ion and get it to read the correct mileage. I was hoping it was going to work the other way and the BCM would update to what was on the original cluster.
      Last edited by greasybob; 09-17-2012, 08:14 AM.

      Comment

      • ToltecasChavez
        Senior Member
        • Apr 2011
        • 408

        #4
        Excellent tips guys!!! I had a 2000 Ford Windstar and the mileage didn't match the old mileage of the car. It would keep the mileage from the donated car. Glad to hear GM allows this, at least in Saturn cars. Any more tips and info on keeping the original mileage would be appreciated. Regards, Chavez.

        Comment

        • greasybob
          Senior Member
          • May 2008
          • 1590

          #5
          Ok, so I got a new BCM from GM but I'm a little scared to program it now that I don't have an instrument cluster with the correct mileage on it anymore. When I flashed the used BCM to the vehicle I don't remember any screens coming up that would allow me to enter the mileage. A screen did come up that instructed me that if a screen that would allow me to enter the mileage did not come up then I was to proceed to unplug the cluster and plug it back in after the programming. This has led me to believe that the new BCM will learn the mileage from the cluster. The TSB I found on where the mileage stored on various GM vehicles says that it is stored in the BCM and that a Tech 2 is neccessary to program it but I see no special functions in the Tech 2 that would allow this and I see no functions an the Tech 2 or on SPS that would allow programming the mileage into the cluster, old or new. Any thoughts on this ?

          Comment

          • USpMD
            Senior Member
            • Oct 2010
            • 171

            #6
            Hi Bob
            I have run into this as well, every time I get a call to reprogram a Saturn BCM I get that here we go again feeling, see GM TSB #PIC3843D, preform the BCM reprogram with the IPC unpluged just as you did last time, then key off 30 seconds, this should keep the IPC from corupting the BCM
            "I wanna help the helpless, but I could careless about the clueless". Dennis Miller

            Comment

            • greasybob
              Senior Member
              • May 2008
              • 1590

              #7
              Here is the screen you will get when using GM service programming for an instrument cluster or BCM when the correct mileage has to be entered. I have a question concerning the proper procedure. If I just start to enter the digits where at the left of the zeros where the curser is flashing, as I enter each digit the zeros will just move to the right and will not be replaced by the digit I entered. Should I just continue in this fashion and just ignore all the zeros or should I move the curser to the right of the zeros and backspace to erase them and then enter the correct mileage or just erase enough zeros so they are replaced by my digits with the remaining zeros to the left of the mileage ? A long question I know but not sure how else to state it.
              Attached Files

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              • ToltecasChavez
                Senior Member
                • Apr 2011
                • 408

                #8
                Just a quick question guys, does the mileage get stored in the BCM or Instrument Cluster? I always have this mileage problem when switching clusters in Ford Windstar vans. I've never been asked by the program to enter the mileage when swapping used clusters. Do I have to reprogram the BCM and THEN it'll ask about mileage? Thank you in advance. Regards, Chavez.

                Comment

                • greasybob
                  Senior Member
                  • May 2008
                  • 1590

                  #9
                  As to the question of where the mileage is stored on these vehicles the answer is BCM according to GM. However the cluster remembers the last odometer reading sent to it by the BCM. If the last sent data does not match the current data (changed cluster or BCM) the odometer will not work. As to the question of how to enter the mileage when programming a new BCM, I was instructed to erase the zeros and then enter the correct odometer reading.

                  Comment

                  • ToltecasChavez
                    Senior Member
                    • Apr 2011
                    • 408

                    #10
                    Thank you very much GreasyBob, that clears up that hassle for me. I guess there is no way to change the mileage unless u buy both new and program the mileage. Used ones may not work. Thank you again. Regards, Chavez

                    Comment

                    • greasybob
                      Senior Member
                      • May 2008
                      • 1590

                      #11
                      If you want to know in which module the mileage is stored and how it is programmed check out GM TSB 07-08-49-020E

                      Comment

                      • Anks329
                        Junior Member
                        • Oct 2020
                        • 1

                        #12
                        So, I know this is a super old thread, but is there a way to view the current mileage on the BCM through Tech2 on cobalt?

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