ECM - Rush to Replace? Why?

[KoboldTaco]

Hey guys -

Don’t throw a tomato at me if this is you. I notice a lot of threads when trying to diagnose a tricky issue, folks are quick to ask if an ECM replacement is required. I realize Chrysler is not known for electrical system stability, but I think an unusual amount of folks ask if they should replace the ECM. What I don't see is:

- any electrical system isolation/troubleshooting
- wiggle testing
- relay / fuse testing
- ground testing
- Code reading, system checking with a proper OBD II computer and diagnostic solution

I also just saw a thread where a battery had not been replaced in over 10 years and ECM replacement was mentioned. Again, I'm not trying to be critical but I am for sure curious if Chrysler had a bad run of computers for a number of years?

What are your thoughts? Do you notice the same thing? Are the ECMs all crap and a logical place to start? It feels not, but that's just me.

 

[alpinegreenneon]

The ECM is almost always the last possibility listed in the FSM for possible causes for just about any code. Too many so-called mechanics are just parts changers. Replacing a ECM is just a quick easy money maker and rarely fixes the problem. There are actual codes for a failed ECM. The only time I have ever seen a failure in one of my vehicles, there was a code for an internal failure but the truck ran just fine.

 

[pacofortacos]

In my experience, it is extremely rare for a Mopar ECM to fail - almost always something else has failed.

 

[KoboldTaco]

The ECM is almost always the last possibility listed in the FSM for possible causes for just about any code. Too many so-called mechanics are just parts changers. Replacing a ECM is just a quick easy money maker and rarely fixes the problem. There are actual codes for a failed ECM. The only time I have ever seen a failure in one of my vehicles, there was a code for an internal failure but the truck ran just fine.

That is a good point to reference the type of backyard mechanic that will just swap out the part vs. Understand why he/she is swapping it out. I believe the former director of flight operations at NASA was famous for saying ” let's not make the problem worse by guessing” when handling the Apollo 13 incident. None of that when swapping out the ECM eh?