What this code means

Component / fault: Vehicle speed sensor.
Reported detail: abnormal rate of change.
FMI 10 in the SAE J1939 / Caterpillar CDL convention means: Abnormal rate of change — see the full FMI reference table.

On a Caterpillar display this code may appear as MID/CID 84 with FMI 10, or in the older PID/SID style. Wording of the reported detail follows the public Caterpillar fault-code listing cited below.

First checks (general, for this failure type)

The value is changing at an impossible rate. Treat as an intermittent connection first: connectors, harness rub points, ground straps.

These are general electrical checks for FMI 10 faults, not a substitute for the model-specific test procedure. If the fault is active and the machine is derated or shut down, follow the service manual for your model and serial prefix.

Need the part?

If the checks point to a failed sensor, solenoid or harness part, send us the code (84 / FMI 10), the machine model and serial number — we quote genuine and OEM replacement parts for export.

Same component, other failure modes

FMI 0 FMI 1 FMI 2 FMI 8 FMI 14