r/Duramax•4 yr. ago

Another FICM…

What could cause a ficm to fail? I have a 2004.5 LLY with 175k on it. 4 years ago, my truck started dying randomly. It would usually restart. That was repaired by replacing the ficm with a used unit. I may have 10k miles on it since then. Friday night it happened again. This time, it’s blowing the edu fuse anytime the ficm is plugged in and key on. My batteries are new and good. My charging system is healthy. Am I unlucky? Is it possible something in the truck is killing the module? I do have a code for the MIL I haven’t been able to figure out. Could that be related?

Posted Jun 13, 2022, 10:54 AM UTC

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tuskenbmxer•4 yr. ago

I think the LLY FICMs are a little prone to failure. I have an '05 w/ 180,000 miles that's down right now because I had to pull the FICM and send it out for a rebuild.

On the other hand, I have an '01 LB7 with 1.3 million miles and on the original FICM....never an issue with it.

MplechaOP•4 yr. ago

Thanks

CountryBoydCustoms•4 yr. ago

It's common on the lly for the wiring harness to rub on the bracket right near the ficm so check there and ensure that it's good would be the first step. in My experience ficm failing isn't common wiring harness is

MplechaOP•4 yr. ago

That was repaired before I got the truck back in 2012. There’s a section of the harness with a heater hose zip tied around it by the alternator. I’ll look there for any damage.