Important Reflash Warning for Cummins ECM's
Over the last week four unrecoverable 6.7L ECM flash failures occurred after being programmed with EFILive. Due to these failures occurring on or around the time we released a software update, we initially thought the failures may have been caused by that recent update, however further investigation revealed that the timing of the failures was just a coincidence.
Unfortunately for one customer this was the second time an ECM flash had failed. EFILive tracked both ECM failures down to the same corrupt file being flashed into the ECM. The ECM was 100% stock and as yet we are unable to explain how the file became corrupt. We are confident this particular customer’s issue was not due to the remnants of a box tuner that was “returned to stock”.
The next three cases highlight a problem that many of you will encounter when you tune Cummins controllers. These failures occurred after the ECM’s were “returned to stock” using a box tuner. After being “returned to stock” the contents of the (supposedly stock) ECM were used as a base tune for EFILive. This is something we know many of you have done without issues in the past, however in this case it is clear that particular ECM operating systems and certain updates from a box tuner caused the problem.
We will try and explain in layman’s terms that although the problems occurred after the truck was flashed with EFILive; the fault is not actually caused by EFILive. When EFILive flashes a Cummins ECM it is done by the book. The ECM is programmed with very detailed index information that tells the EFILive software how much memory needs to be flashed and where that memory is located. If the size and/or location of the memory changes without the index information being updated to match then the ECM (and therefore EFILive) cannot accurately update that memory. It is like adding new pages to a book but not updating the table of contents. The old table of contents will have page numbers that are either wrong or indicate non-existent pages.
So what if the box tuners do not update the index info correctly, that should be no concern to EFILive. The ECM flashed by the box tuner still operates correctly – right? That’s true, but by not updating the index, the box tuner has caused two problems, one immediate problem and one dormant problem just waiting to bite tuners in the ass.
The first problem is, the ECM no longer “knows” where all its memory is located. It needs to know where all its memory is located so that it can verify the integrity of the ECM. It verifies the ECM by calculating a checksum of the memory in the ECM. How does it know which memory to verify? By referring to the index. Because the index is now faulty, the ECM cannot calculate the checksum and cannot verify the integrity of the ECM. The box tuner solution to that problem is to just switch off the checksum verification (we've all seen that in many tune files). With the checksum disabled, if anything failed in the ECM then the ECM is not able to detect or report the failure, in fact the ECM won’t even know that a failure occurred and would continue to operate the engine under non-deterministic conditions, probably with disastrous results.
The second problem is more serious, but it didn’t have to be if only the box tuners would perform as advertised and actually return the ECM to stock when commanded to do so. Unfortunately when commanded to “return to stock”, the box tuners leave non-stock modifications in the memory, which quite frankly shouldn't be the case if you've chosen to "return to stock tuning". Stock to us means as it was the day it left the factory.
When EFILive is used to read out the tune that is now supposedly “returned to stock”, the tune that is read out still contains some of the non-stock modifications. Some of the modifications are located in memory areas that are included in the index, some modifications are located in memory areas that should be included in the index but are not. The modifications that reside in memory areas that are not included in the index are not flashed back into the ECM because there is no way to know that modified memory exists. The ECM ends up with some stock and some non-stock memory. Because the memory is now neither fully-stock nor fully modified the ECM tries to execute non-existent program code which causes the CPU to fault and reset, only to fault again and reset again over and over and over. It would be similar to repeatedly pressing the reset button on your PC and wondering why it never boots up and starts operating.
We've battled similar problems with the 5.9L ECM too, they aren't immune, we've just been fortunate that none of the failures with the 5.9L have been fatal to the ECM. Since this latest event we have checked numerous “returned to stock” 6.7L tunes and were shocked at how widespread this problem really is. All we can say is we have been really lucky up to now this hasn't happened sooner.
We have tried to implement a check system to warn of incomplete files for 6.7L ECMs (as was done for the 5.9L many months ago), but we don't have access to each and every update the box tuner manufacturers have made, so we cannot guarantee that every one of them will be detected correctly. It is for that very reason EFILIive recommends this to all users: If you have at any stage had 'any' other tuner on your truck, before you read the ECM with our software to get a base file, that you have the ECM returned to stock by the dealer, or you speak with your reseller to ensure you get a 100% stock factory tune to begin with. Having the ECM returned to stock by the dealer will remove all traces of any tuner.
EFILive has assisted the four users who were affected by these recent failures by covering all costs for replacement ECMs and V2 licenses. This is not something we want to repeat again which is why we recommended that you do not obtain your base tune from your ECM if it's ever been programmed outside of the dealership before.
Regards,
EFILive
