What causes a SPN 284 code?

SPN 284 can be triggered by several issues — see the verified probable causes and step-by-step diagnostics shared by mechanics and owners on OBDIY.

Can I drive with a SPN 284 code?

Drivability depends on the severity. Check the severity rating and verified driver reports on this page before continuing to drive with SPN 284 active.

How do I fix SPN 284?

Follow the step-by-step diagnostic on this page, then read the verified fixes contributed by other Heavy Truck owners — the answer marked "Verified Cause" worked for the original poster.

OBDIY

J1939 SPN

SPN 284

J1939 SPN 284 — Fuel/Air parameter

What it means

Engine Position Information; indicates a loss of synchronization or invalid signal from the crankshaft or camshaft position sensors required for timing fuel injection and air intake.