FMI 12 — Bad intelligent device or component
A smart component reported its own internal failure. The device told the ECM it is bad.
Common causes
- Internal electronics failure in a smart sensor or module
- Corrupt internal calibration
- Power supply out of range to the device
- Water intrusion
What to test, in order
- Verify supply voltage and ground quality at the device
- Check for a firmware/calibration update for that device
- Cycle power and see whether the fault self-reports again
- Replace the device when supply and network check out
Codes we document with FMI 12
The reference is free. The diagnosis is Pro.
Every SPN and FMI page on this site stays open — no account needed. Pro members can take the code into Blue Collar AI with the VIN, symptoms and photos, keep per-truck history, and print a work order. $14.99 a month or $99.99 a year.