ECM/2005 gmc envoy denali.. please give your opinion?

[? Shery ?]

I have posted the last few days regarding a problem with my GMC 2005 envoy denali. It is stalling out on me ONLY after engine warms up.. on idle it cuts/stalls out AND after I drive it for a while when I turn it off it wont start back up.. turns over but wont start.

I have in the past week had all the filters etc changed... still same problem.

I took it to a mechanic yesterday that told me that the codes it was giving are manufacturer codes that only they can repair .. the mechanic told me he thinks it is the entire emc computer.

It had been at the dealership for a day and a half.. they said it started fine.. I advised them to let the car run and eventually it will stall out... and they did... the car then stalled for them..

the latest news is that they can not find anything wrong with any of the codes it is throwing out... they told me that they ordered a new ecm and will put that in and re-run the diag. and if nothing shows then it means that it is the emc..

my question is as follows... would they order an entire new emc if they did not have strong reason to believe that is indeed the problem. AND before they would order that.. would they specifally go through all the codes and check the corresponding componet, so I am wondering if they have checked everything else.. or just quessing it may be the ecm.

I am hoping for a YES answer that the emc looks to be bad.. due to it is under warranty up to 80k miles... if it is ANYTHING else I have to pay for it... I have no funds to pay for it and no transportation so I am hoping that it is a faulty ecm and replacing it will solve the problem.

any help is appreciated... hopefully you will give me good news that it in fact does sounds like the emc is bad.

also is it common for ecm to go bad with 73k miles on a vech.. the person at the dealership said it is kind of rare.

thanks in advance

 

[John]

Well, the dealerships have an advantage in this respect ,over other mechanics. They can just take a component like a emc, plug it into your car. Then if that works, well . Problem solved. ( its called guessing)
If it does not fix the prob, then they can just remove it and put it back on the shelf.
If they put it in and there is still a problem. Then they will continue to try to find the problem.
If they find the problem and it is something else. Then they will prob say it was the emc anyway. So they can sell the emc. But in your case this would be a good thing as it would covered buy warrenty.
Make nice with the service writer, wink at him. Because if it turns out to be something else. They can just say it was emc and bill it to warrentee. They do things like that all the time. They really dont care as long as they make money.

 

[Rob]

If the Dealership is doing it I dont see why they would just throw parts at it, I personally have worked on cars and went through the diagnostic procedure and ended up ordering an ECM and had doubts that would fix it, but in the end it did. For some reason when ECMs' go bad sometime they cause weird scenarios that are hard to locate.

I have worked on cars where the ECM only lasted 60,000 miles, my Saturn L300s' ECM went out at 15,000 miles. so to answer the second part of your question, it is common for ECMs' to go bad that early

 

[Richard S]

GM technicians use what is refered to as a trouble tree and each code has a tree that is used to diagnosis that code. It takes you through all of the possibilities of each component and support component. Example; Code 472 which I just made up is for wheel speed sensor malfunction of the right front wheel. The tree will ask is there a reference voltage at the sensor, yes/no. below the yes is a course of action and a different course of action is below the no. You follow this tree through all of the tests that it asks and it leads you to the answer by proscess of elimination. It can take up to 30 minutes per trouble tree test code and this is why they charge so much. In answer to your question, the ECM is seldom at fault but it does happen. If the vehicle was jump started in the past and not done correctly, it can spike the ECM. Hope things turn out on the good side for you.