What causes a SPN 443 code?

SPN 443 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 443 code?

Drivability depends on the severity. Check the severity rating and verified driver reports on this page before continuing to drive with SPN 443 active.

How do I fix SPN 443?

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 443

J1939 SPN 443 — Fuel/Air parameter

What it means

This is a data-link fault indicating that the Fuel/Air control parameters received over the J1939 network are invalid or out of range.