ECM in unknown state :(

[SmokinDuradog]

Seems like everything I touch with EFI LIve lately the ECM goes into an unkown state!!! I have calibrated my truck atleast 30 times with TCM changes and ECm changes and have never ha this issue. I tried to help a few friends out and now that seems all I can do:( Does this mean the ECM is fried? Is there anyway to recover the ECM from this state? I know alot of people have these same issues. I was able to upload stock cal. with no problems then downloaded the new cal. with what seems is the normal hickups disconnect everything and connect it back a few times before it would download but it took it ok. Now the truck wont start??

Is there some kind of anti theft or something the ECM will go into if you unplug it to add a DSP5 switch. Its for an LB7. Unplugged the ECM plugged signal pin into 69 and the ground into 49 3x checked that all the pins looked good. BUt the truck wont start fires and then shuts off immediately. Only after I had uploaded the cal and downloaded the new cal would EFI LIve no longer recognize the ECM??? If anyone has any ideas please feel free to post. Thanks for the info.

[GMPX]

Can you read back out the tune currently in the ECM?

[SmokinDuradog]

I am unable to upload or download anything to the ECM while the ECM is in the truck. Fortunately we have another LB7 truck at the shop so I was able to download the new operating system for the DSP5 and the its calibrations into the ECM via the other LB7 and put it back into the truck. The truck still will not start it just fires and dies instantly. Its almost like there is some kind of anti theft issue not allowing it to communicate with the truck :( Only thing I really know to do now is take it to the dealer and c if they can flash the ECM?? Any help would be great not sure if there is a way to unlock the ECM or something??

[chevy052500hd]

try doing a theft relearn using flash scan. also plug in you vin on gm tis site to make sure you swapped in the proper os from the other lb7.


http://tis2web.service.gm.com/tis2web

enter both vins and make sure os's match, but your problem seems to be a theft relearn problem, after it dies does the security lock light stay on?

[GMPX]

I am unable to upload or download anything to the ECM while the ECM is in the truck. Fortunately we have another LB7 truck at the shop so I was able to download the new operating system for the DSP5 and the its calibrations into the ECM via the other LB7 and put it back into the truck.That in itself tells me there is some issues with that truck if you are able to plug the ECM in another vehicle and it programs fine.
Be very wary of aftermarket add-ons on the data bus.

To test if it's the theft system, you can disable it in the tune and try to run it after that to see if it keeps running.

Cheers,
Ross

[SmokinDuradog]

Hey guys thanks for the info. Going to put the ECM back in the other truck and do a relearn on the security and also try disabling it. Hopefully one of those will work. I forgot to mention also that the power locks and the power windows wont work. The information center on the dash says couple of different things after you try to start and dies. Service 4wd and battery is not charging. As far as I can tell that little security lock goes off shortly after you keep up.

[SmokinDuradog]

Ok well just for fun I tried talking to the ECM while it was in the truck it belongs to that normally will not communicate with the ECM. I was able to a VAT relink?? Is that what needs to be done as far as having the ECM relearn security? After I did that it told me to cycle the key. I was able to get the door dinger working again from this operation LOL:confused: So I figured I would try to download a full reflash with the DSP5 OS and the calibration it seemed to be going just fine on slow with ALT Keys then all of a sudden I keep getting the message retrying previous block?? every 11 seconds it says that not sure if its safe to stop and try a reflash again.

[SmokinDuradog]

Ok well now I have managed to get the truck into a NO CRANK state :( This really sucks! After it got stuck in that retry previous block crap I had to stop the downl-oad and the ECM is back in an unkown state. So now I have put the ECM back in the other truck and have once again done a full reflash with the new OS and cal. Im sure once i put it back in the truck it still wont start. I suppose only thing to do now is take it to the dealer and bend over :) Im not sure that I will be using EFI Live on anything else 3days now and nothing seems to work.

[chevy052500hd]

did you pull the fuses for the radio? onstar?. There maybe some interference on the buss from these items. Have you tried reprograming back to stock? Something is giving you interference on the data buss on that truck. Aftermarket radio interfaces will cause interference with flashing, it does on my truck so I have to pull the radio fuse. Good luck.

[GMPX]

That in itself tells me there is some issues with that truck if you are able to plug the ECM in another vehicle and it programs fine.
Be very wary of aftermarket add-ons on the data bus.

To test if it's the theft system, you can disable it in the tune and try to run it after that to see if it keeps running.

Cheers,
RossI re-quote myself there.
You have probably put the ECM in a brain dead state now.

[SmokinDuradog]

Well guys thanks for all the info tomorrow Im hoping I will find the root of the problem. This is what i've narrowed it down to after digging long enough. So here goes my long winded explanation of what I think is wrong and hopefully tomorrow or Monday whenever I have time should give me the verdict.

The ECM works fine it has no issues it works on the other truck with no problems. The purple wire going into the OBD2 connection inside the truck is the CAN Line that communicates between the the two. This line actualy changes color somewhere down the line to Dark Green and goes into pin 58 if I remember correctly on the BLUE side of the ECM. NOW then the YELLOW wire that comes out of the ECM and goes to the BCM seems to be where the problem lies. Either the line has a short in it or the BCM is fried. I placed a wire directly into pin 58 and pulled the Dark Green out of the ECM then hooked up a power and ground using an OBD2 connector hooked up EFI LIve outside the truck not using the OBD2 connector itself. As you might guess still had the same issue could not talk to the ECM it was in unkown state YADDA YADDA YADDA! Now then I pulled the yellow wire out of the ECM that talks directly to the BCM. Wouldnt you know I was able to upload and download as much as I wanted directly to the ECM. A shorted wire or bad BCM is the only thing I can think of atm as to why the battery keeps going dead.

So what I plan on doing is checking the yellow wire for continuity all the way from its pin in the ECM to the BCM. If the wire seems to check out then I would think it is the BCM. I guess if none of these steps fixes then... I give up LOL! I will keep you all updated :)

[SmokinDuradog]

I forgot to update everyone on the final outcome of this little "PROBLEM" lol! All I had to do is unplug the BCM and plug it back in I had no issues communicating with the truck after I did that :doh2: Was a great learning process now looking back. Learned a lot about trouble shooting in general and EFI Live itself.