FMI 8 — Abnormal frequency, pulse width, or period
A frequency- or PWM-type signal is outside the expected range or shape.
What it typically points to
Damaged speed sensor or tone ring, wrong air gap, electrical noise, or a failing PWM sensor.
Codes with FMI 8
- SPN 84 FMI 8Wheel-Based Vehicle Speed
- SPN 190 FMI 8Engine Speed
- SPN 636 FMI 8Engine Position Sensor (Camshaft)
- SPN 637 FMI 8Engine Timing Sensor (Crankshaft)