FMI 5 — Current below normal or open circuit
The ECM is commanding a device on but almost no current flows. The circuit is open somewhere: connector, wire or the coil in the device.
Common causes
- Open winding in a solenoid, injector or actuator
- Broken wire or backed-out terminal
- Unplugged connector
- Blown fuse feeding the device
What to test, in order
- Measure coil resistance at the device and compare with spec
- Check for the supply feed at the device connector with the key on
- Continuity-check each wire end to end from the ECM connector
- Substitute a known-good device only after the wiring proves good
Codes we document with FMI 5
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.