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BACK INFO: so few weeks ago, my truck had a crank no start, did the troubleshooting I determined a FICM issue so I changed out the FICM - I discovered that one of the plugs had vibrated loose on the truck, causing the issue. I went ahead and changed to the 58 V unit that I had sitting on the shelf just to see what it would do.
- My truck is always had extended cranks when cold were not plugged in. When I swapped FICMS. The truck through a FICM software SYNC code but my extended cold weather crank issue disappeared. Nine Below Zero, over Thanksgiving, cycled the glow plugs the truck fired right up on a couple turnovers.
Last weekend I went and picked up a project truck for one of the kids, so change to my towing tune
- no I did not pull the FICM, relay fuse, and I think I regret it now as my extended cold-weather crank has returned, and the FICM software sync code has disappeared
if I swap the FICM back, will it throw the software code and resolve my cold weather starts????
I can say that I have a truck I diagnosed with FICM low voltage issues. I pulled a known good FICM from another truck and the problem truck started right up.
Because it was easier I put the bad FICM in the donor truck, and it started right up also. I never checked the FICM voltage in the donor truck, but I know it had better batteries.
Just for fun you might do a capacity check on your batteries and voltage drop test on your cables, if you haven't already.
What are you using to read the codes? Can you post the exact code you're getting? I'm not aware of a FICM SW Sync code - are you SURE it's not a CKP or CMP code or a SW compatability code? Are you actually watching the FICM SYNC & CAM/CRANK SYNC (aka SYNC) PID's?
As for not pulling the FICM relay - The only time you need to pull the FICM relay is when you're changing the tune on the FICM itself. If you're just tuning the PCM, there is no need to pull the FICM relay.
What are you using to read the codes? Can you post the exact code you're getting? I'm not aware of a FICM SW Sync code - are you SURE it's not a CKP or CMP code or a SW compatability code? Are you actually watching the FICM SYNC & CAM/CRANK SYNC (aka SYNC) PID's?
As for not pulling the FICM relay - The only time you need to pull the FICM relay is when you're changing the tune on the FICM itself. If you're just tuning the PCM, there is no need to pull the FICM relay.
I can say that I have a truck I diagnosed with FICM low voltage issues. I pulled a known good FICM from another truck and the problem truck started right up.
Because it was easier I put the bad FICM in the donor truck, and it started right up also. I never checked the FICM voltage in the donor truck, but I know it had better batteries.
Just for fun you might do a capacity check on your batteries and voltage drop test on your cables, if you haven't already.