Re: ECM Killed by mobile Cat Mechanic

hard to tell who is really to blame and what went wrong in your case, but this sound somewhat familiar to other stories I hear once in a while.


every time you flash an ECM, yes, there's always a slight risk that something goes wrong.


also, most engine manufacturers do not make their own ECM, these are programmable devices made by companies such as Bosch, Denso, Delphi, Siemens, etc


I uses CAT ET almost everyday, and every time I install an update, I cross my fingers.

this is really not specfic to CAT engines.

It's the daily reality of every technicians nowadays.


The task is pretty straight forward, but there is a certain degree of action in the process of flashing an ECM that is beyond the Tech's control. 










Re: ECM Killed by mobile Cat Mechanic

thanx for your reply.  I'll get my engine serial # for you this weekend.  It's in the truck right now.  I do know that my software is stored with CAT now, so if I have a similiar issue in the future, it can be reprogramed by any CAT dealer when they look it up.  I really don't believe in the coincidence theory, although it is possible.   I just was not having any driveability issue, other than the exhaust brake not working, & that probably is not considered a drivability issue.  I subscribe more to an honest mistake was made.  I'll dig out the engine serial # & post for you.....thanx again dave for your reply.     dan

Super Contributor

Re: ECM Killed by mobile Cat Mechanic

It's highly unlikely that connecting ET to the ECM caused any issues. Probably just coincidence. ECMs fail sometimes. What is the engine serial number and software part number?

ECM Killed by mobile Cat Mechanic

Perhaps some of you more seasoned Cat folks can offer me an opinion on whether I should just bite the bullet & fork out 3K, or tell the shop you broke it, you fix it.  I'll give you all a brief background on what happened. 

  The engine is a cat 3126E, in a ford supercrewzer.  I took my truck into a heavy duty repair shop for a steering issue & to diagnose why the exhaust brake does not work.  After troubleshooting as much as the shop could, they determined the issue could be a parameter on the ecm not allowing the signal/voltgage from the ecm to the dash switch.  Since they are not a CAT shop with cat et software, they hired a mobile cat man with his laptop to check the ecm.  The cat man was successful in downloading all the parameters & trim files, and then sometime into his diagnosis the ecm no longer would communicate with his laptop.  The ecm was pulled out & sent off to a cat dealer & he determined the ecm would not communicate.  It was dead.  I needed my truck to run, so I told the dealership to program the new ecm & it was then installed & truck runs fine, just like before. This cost me 3K.   My question is, does this happen often?  My beef is that I was not having any driveability issues or running/starting issues.  I took the truck in to troubleshoot the exhaust brake, look at the ecm, & in the process it is killed.  Am I just on the hook for this?  The pisser is the exhaust brake still does not work!  The attitude of the mobile cat man is "sxxt" happens sometimes, & we are not responsible for this.  I do believe that honest mistakes can happen, & perhaps the mobile cat man accidently entered a wrong file or something.  Is this possible that the mobile man can kill the permanent firmware in the ecm?  If anyone has an experience to share or an opinion on what is fair on how to resolve this I would appreciate it.  I have subsequently read that ecm's do go bad, but usually there are some telltale symptons of it going bad first.  Thanks for your time.