FMI 16 — Data valid but above normal operating range — moderately severe level
Real reading, clearly high. Usually the middle warning stage before a derate.
Common causes
- Developing restriction, overheat or overpressure
- Control device not regulating down
- Sensor drift
What to test, in order
- Verify against a mechanical gauge or second sensor
- Inspect the flow path for restriction
- Test the control device's regulating range
- Watch for the value climbing into the most-severe threshold
Codes we document with FMI 16
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.